How much amplifier power do you need?

Hello Bombaywalla,
Though I have not read this exact article but I have read something similar elsewhere.

Though I agree with all the mathematical calculations as well the conclusion but I was wondering what exactly this means in a more practical world.

Considering a good bookshelf speaker with an average of 87db sensitivity, the calculation works out as follows:

Sensitivity at 9-10 ft away from the speakers would be 87-7 = 80db. As per the article, to gain unclipped peak of 105db, we are talking about a dynamic range of 105 - 80 = 25db.
Which means two things at the least going by the table provided in the article:

1. An amplifier needs to give out 300-350 watts of clean power without any strain or clipping (at this point I am keeping the impedance factor outside) when the music and speaker demands. To do this, an amp should have a minimum of 500 watts in reserve (thats a conservative figure considering the amp is very well designed) to be able to supply 300-350 unstrained watts.

2. The speaker should also have the capability of handling at least 500 watts without clipping so that it behaves in a composed manner when fed with a peak of 300-350 watts.

Now, how many speakers and amps with a real world price tag can do that ?
Does that mean real hifi starts only up there ?

Can a mid sized living room handle 105db peaks ? Ok, I know acoustic treatments can do a lot but for all practical purposes, are such level of loudness really listenable at homes ?

abhi.pani schrieb:

Hello Bombaywalla, Considering a good bookshelf speaker with an average of 87db sensitivity, the calculation works out as follows: Sensitivity at 9-10 ft away from the speakers would be 87-7 = 80db.

slight error on your part here, Abhi. The SPL level at, say, 3m (10ft) would be more like:
87dB - 6dB (for distance doubling) - 3dB (for increase in distance from 2m to 3m) - 1,2dB for furniture, drapes, etc. = 76, 77dB.

abhi.pani schrieb:

As per the article, to gain unclipped peak of 105db, we are talking about a dynamic range of 105 - 80 = 25db.

With the new calculations, the dBW needed in the power amp would be 105dB - 76dB or 77dB = 29dB at the most.

abhi.pani schrieb:

Which means two things at the least going by the table provided in the article: 1. An amplifier needs to give out 300-350 watts of clean power without any strain or clipping (at this point I am keeping the impedance factor outside) when the music and speaker demands. To do this, an amp should have a minimum of 500 watts in reserve (thats a conservative figure considering the amp is very well designed) to be able to supply 300-350 unstrained watts.

Do keep in mind that it's 105dB PEAK & not steady-state. The calculation was: how much amplifier wattage you need to generate a 105dB PEAK. So, peak power calculated should be the peak power of the power amp. With the new calculations that works out to be ~ 800W/ch (which is indeed a large number).
Do keep in mind, that we need to subtract 3dB from the 105dB number because we are listening in stereo i.e. we have 2 speakers. Thus, to hear a 105dB peak, each speaker needs to generate a 102dB peak. When we add the sound from 2 speakers, we get a doubling of the sound effect, which 3dB. So, 102dB (left channel) + 102dB (right channel) = 105dB.

abhi.pani schrieb:

2. The speaker should also have the capability of handling at least 500 watts without clipping so that it behaves in a composed manner when fed with a peak of 300-350 watts.

yes, the speaker should be able to handle 105dB peaks. Often 2nd order x-over & higher order x-over speakers will be capable of that. Wattage of the power amp is converted to electric current that creates those PEAKS in the speaker driver. And, you'll see that most speakers, even the humbler types, have relatively high handling PEAK power.

abhi.pani schrieb:

Now, how many speakers and amps with a real world price tag can do that ?

yes, you are correct: there are few large amps out there that can put out high wattage & it does get costly, no doubt. But, what this article is telling you is that, from a SPL stand-point, how much PEAK wattage is needed.
There are a few other factors in the mix that the article does not go into (beyond its scope) such as the speaker impedance vs. frequency & the room acoustics/gain.
If the impedance of the speaker is high, then, for the same wattage output, the amplifier will be creating a larger voltage swing inside the speaker & you'll be getting more SPL. IOW, the amp has to work less hard compared to, say, a speaker that is very low impedance. This could have the effect of reducing the PEAK wattage required from the amplifer.
The room: there is some gain from this element that can enhance the SPL. If you take the room gain into account, it could further reduce the PEAK wattage requirement.
Every few dB gained from the speaker impedance & room has a dramatic effect on reducing the peak amplifier wattage requirement.
You need take ALL of this into account when making a decision. The article merely starts off this thought process by giving you a feel for which region of wattage you should be looking at; it was never mean to be the final answer.

abhi.pani schrieb:

Does that mean real hifi starts only up there ?

I think that it does. If you are looking for real-world, concert-level dynamics then you will need lots of amplifer power. There's no doubt about that.
The real question for you (& each listener) is: do I REALLY want that?
Or, do you want something more scaled down & then you have to define that scaled down version for yourself & buy your equipment accordingly.

abhi.pani schrieb:

Can a mid sized living room handle 105db peaks ? Ok, I know acoustic treatments can do a lot but for all practical purposes, are such level of loudness really listenable at homes ?

Oh sure!! Peak of 105dB are definitely sustainable in mid-sized living rooms. By mid-size I mean 20 ft X 20ft types. Mid sized living rooms will not be able to sustain deep bass - the cut off is likely to around 45Hz. So, you end up w/o the 20Hz-40Hz octave but in most cases you do not miss it (in classical music you miss it the most).

Bombaywalla said:

Oh sure!! Peak of 105dB are definitely sustainable in mid-sized living rooms. By mid-size I mean 20 ft X 20ft types. Mid sized living rooms will not be able to sustain deep bass - the cut off is likely to around 45Hz. So, you end up w/o the 20Hz-40Hz octave but in most cases you do not miss it

Can you guys please point me to articles / link on the 'net that provide details of how to calculate :

a. Max Acoustic levels that a room can sustain ?

b. Lowest Freq that a room can reproduce ?

Many Thanks

Amp_Nut schrieb:

Bombaywalla said: Oh sure!! Peak of 105dB are definitely sustainable in mid-sized living rooms. By mid-size I mean 20 ft X 20ft types. Mid sized living rooms will not be able to sustain deep bass - the cut off is likely to around 45Hz. So, you end up w/o the 20Hz-40Hz octave but in most cases you do not miss it Can you guys please point me to articles / link on the 'net that provide details of how to calculate : a. Max Acoustic levels that a room can sustain ? b. Lowest Freq that a room can reproduce ? Many Thanks

here are some links for predicting the basic acoustic properties of a room
Predicting the basic acoustic properties of a rectilinear control room

TRAPPING BASS IN YOUR PROJECT STUDIO

Calculate Room Modes
This is a very cool site - it actually calculates all the room modes: axial, tangential & oblique.

According to me you 1st question is that pertaining much more to electronics & less to the room. 1st you need to the capability to generate 105dB/120dB or whatever dB peaks. The room gain/attenuation will make those peaks sound good/bad depending on how well the room is treated. Also, if the room is too small & you have a high SPL in that room one could damage one's ears. OTOH, if the room it too big, one would need much more amplifier power to get the desired SPL.

Maximum recommended sound pressure levels in rooms

Acoustical Design for Architects
This links appears to be off-topic but I do not think so! If you scroll down past 1/4 & before 1/2 you can read some info on "Rooms for Music". Then around the 1/2 mark, read up on "Room Sound Level".
Figure 13 is instructive tho' I do not know if it answers your question.

Excavating Real Deep Bass
this is a good article about getting the 20-40Hz deep bass in your room using Axiom's sub. The author talks about SPLs obtainable in a typical room.

Hello Bombaywalla,

Thanks for the many links posted. Some are extremely informative ( even if not on the topic I mentioned ! ) while others are ......


Bombaywalla said:

According to me you 1st question is that pertaining much more to electronics & less to the room. 1st you need to the capability to generate 105dB/120dB or whatever dB peaks. The room gain/attenuation will make those peaks sound good/bad depending on how well the room is treated. Also, if the room is too small & you have a high SPL in that room one could damage one's ears. OTOH, if the room it too big, one would need much more amplifier power to get the desired SPL.

Infact, neither of my 2 questions were related to electronics capability...

In my 1st question I had asked :

a. Max Acoustic levels that a room can sustain ?

As I had mentioned, the question was based on your statement:

Oh sure!! Peak of 105 dB are definitely sustainable in mid-sized living rooms.

This seems to indicate ( to me ? ) that there is a limit to the acoustic level that a room of any size will 'sustain.'

Similar query for my 2nd question.

The references mentioned by you, provide a wealth of info, but do not categorically answer my queries.

To state my queries explicitly with examples :

Let us assume a room size of 9 feet height x 12 feet x 15 feet, and make any reasonable assumptions of its RT time, etc ( you are welcome to state these assumptions.)

Then what is the :

a. Max Acoustic levels that this room can sustain ? ( eg 105 dB ??? )

b. Lowest Freq that can be reproduced in this room ? ( eg 20 Hz ??? )

Basically, I am looking for practical, indicative answers ( if they exist )

Many Thanks.

Oh sure!! Peak of 105 dB are definitely sustainable in mid-sized living rooms. This seems to indicate ( to me ? ) that there is a limit to the acoustic level that a room of any size will 'sustain.'

No, Amp_Nut, I did not write the above statement with an underlying indication that a room has some maximum acoustic level that it can sustain.
In fact, the statement had other underlying tones:
* it is practical & affordable to own an amplifier-speaker system that will produce 105dB SPL peak in a 20X20 mid-sized room &
* the listener would be able to stay/listen to that SPL peak.


Think about it (you're a EE! ) - what would limit the SPL in a room, any room? Any of the factors attenuating the SPL can be overcome by what?????????
By having more powerful an amplifier, the electronics. If you say that your furniture eats up 1-2dB of SPL, increase the amplifier power/wattage by 1-2dB to compensate; if your walls flex & eat up another 1-2dB, further increase the amplifier by another 1-2dB to further compensate. It's getting impractical at this point in terms of amplifier wattage available in the market but, for the sake of argument & taking things to the limit to illustrate a point, who cares! IMO, the room is a passive element & will sustain any SPL as long as you have the amplifier power, the speaker's ability to handle that power & the speaker driver's ability to generate that pistonic motion to create that SPL.
In the end, you might have to run out of the room to avoid ear damage but that's another matter....
The reason that most people cannot obtain these high SPLs in their homes is that budget is limited for the electronics, aethetics have to be taken into account, the poor quality of the AC power corrupts amplifier performance, etc, etc. If you solve these issues, you get yourself closer to being able to reproduce high SPLs efficiently i.e. ensuring that whatever amplifier power you do have is going more towards SPL generation rather than overcoming room, system non-idealities.

b. Lowest Freq that can be reproduced in this room ? ( eg 20 Hz ??? )

Can you not use c=f*lambda & calculate what your room will sustain?? Didn't think of using this simple formula?

Bombaywalla said:

Can you not use c=f*lambda & calculate what your room will sustain?? Didn't think of using this simple formula?

Sir, could you please grind the numbers for me, for a room:
9 feet height x 12 feet x 15 feet

Thanks

P.S: Does the Wavelength or half or quarter wavelength HAVE TO match a room dimension ( even the diagonal ) for it to be reproduced in the room ?

What if the room is not an integral multiple of a specific wavelength ? Will that freq / wavelength not be reproduced in that room ??

I am confused....

Amp_Nut schrieb:

Bombaywalla said: Can you not use c=f*lambda & calculate what your room will sustain?? Didn't think of using this simple formula? Sir, could you please grind the numbers for me, for a room: 9 feet height x 12 feet x 15 feet

Amp_Nut dikra, sue karech???
Not applying yourself re. these calc; want to be spoonfed? You are not in KG anymore.....
Give me your calendar, let me write a note to your parents: "boy is mock smoking pencils in class, daydreaming, Will not apply himself to Maths problem. Please make an appointment to see me at your earliest to discuss your (lazy) son".

Let's please see what numbers you came up with. Thanx.

Bombaywalla, you flatter me....by calling me lazy, when I am ACTUALLY confused and ignorant !

My half baked knowledge tells me :

1. A wavelength ( or its half or quarter ) does NOT need to fit into a room, for the room to be able to reproduce it.

If it does, the room will create a STANDING wave (Resonance) at that wavelength or frequency.

The REPRODUCTION will happen EVEN if there is no standing wave. ( Thank God for that, or we would hear only certain frequencies in a particular room ! )

As an example, if the room established a standing wave at say 150 Hz then 151 Hz wont create a standing wave, but 151 Hz WILL be re-created in the room.

Then there are words of wisdom from stalwarts such as

Linkwitz

I quote:

At frequencies below the lowest room resonance the sound pressure will increase at a rate of 12 dB/oct for a closed box speaker that is flat under anechoic conditions, assuming that the room is completely closed and its surfaces are rigid. This case has some significance for the interior of automobiles.

Similar thought at diyaudio

there is a common misconception that a wavelength has to "fit" inside a a room in order to make audible sound. That the largest room dimension should be at least a half or whatever portion of a wavelength. This is not the case. One can divide the frequency range in three parts: "high" frequencies; those above the Schröder frequency (which typicaly is ~200 Hz). In this frequency range the sound field is reverberant, and there is little use in studying individual room responances since they are so many and close together. "mid" frequencies below the Schröder frequency and above the lowest resonance of the room. For box shaped rooms, this resonance occurs when the longest dimension of the room* is half a wavelength. In this range, room resonances are often troublesome and cause an uneven frequency response. Some frequencies are emphasised and others are attenuated. "low" frequencies, below the "mid" range. If the loudspeaker has a flat response down to DC in free space (which of course is very hypothetical), the response in an airtight room will increase by 12 dB/octave towards lower frequencies. So, contrary to the common belief that low frequencies are hard to generate in a room, it is actually the other way around. Low frequencies are typically amplified inside a room compared to free space.

Bombaywalla, you flatter me....by calling me lazy, when I am ACTUALLY confused and ignorant !

Amp_Nut, I did not mean to denigrate or flatter. I was merely writing with some levity - poking some fun - and it was not to be taken too seriously. After all we are talking audio...
Amp_Nut, what I've learnt is that you are actually quite knowledgeable but you are too modest....

Thanx for sharing that info - my hodge-podge knowledge of room acoustics (gathered as I treated my room) also says similar things altho' I did learn about the 12dB/oct inc in SPL in an airtight room.

Yeah, you are correct: frequencies do not need to fit into a room for them to be reproduced otherwise, as you correctly wrote, we'd not be hearing music as we know it!

OK, getting back to your original question:

Sir, could you please grind the numbers for me, for a room: 9 feet height x 12 feet x 15 feet Thanks

this is what I came up with for standing waves/resonant freq in your room:
* resoances due to axial modes (these are the strongest & the most problematic & room NEEDS to be treated)
37.2Hz + all harmonics -> 15' walls interacting
46.5Hz + all harmonics -> 12' walls interacting
62Hz + all harmonics -> ceiling & floor interacting

* resoances due to tangential modes (amplitude is 6dB down from axial modes):
59.5Hz + all harmonics -> 15' & 12' walls interacting
72.3Hz + all harmonics -> 15' wall & ceiling interacting
77.5Hz + all harmonics -> 12' wall + ceiling interacting

* resonances due to oblique modes (these are 12dB down from axial modes & are caused by all 4 walls + the ceiling + floor interacting)
89.96Hz + all harmonics.

Hope that this answers your question. FWIW.

Hope that this answers your question. FWIW

Actually, I was hoping that you would realise that there is No NEED to grind the numbers. since determining the freq of possible standing waves in a room was not the topic of discussion.

Infact, the conclusion I was pushing towards was that room dimensions DO NOT determine the lowest freq of bass that can be reproduced in a room.

Also the room size does not dictate the max SPL that can be created in a room..

Sorry for this long detour on your topic... Its back to amplifier power

Amp_Nut schrieb:

Hope that this answers your question. FWIW Infact, the conclusion I was pushing towards was that room dimensions DO NOT determine the lowest freq of bass that can be reproduced in a room.

But it determines how accurately it reproduces it.

SQ... Can you please Elaborate ?

Thanks

square_wave schrieb:

Amp_Nut schrieb: Hope that this answers your question. FWIW Infact, the conclusion I was pushing towards was that room dimensions DO NOT determine the lowest freq of bass that can be reproduced in a room. But it determines how accurately it reproduces it.

Amp_Nut, SQ & other members, I have been thinking about this also. I read the same info back when I was tuning my room w/ the ASC TubeTraps & took the info by the stalwarts to be the gospel truth. My main aim was to tune out the resonances in my room & not really care about the lowest freq reproducable. Now, thanx to Amp_Nut, this matter has been resurrected for me.

If the bass freq wave cannot fit into the room then how can one hear it???
Let's take Amp_Nut's room (as he has graciously provided the dimensions earlier). The diagonal along the floor calculates to 19+ feet, which xlates to some 29.3Hz. And, if you take the diagonal from one corner on the floor to the opposite corner on the ceiling then that calculates to some 21 feet, which xlates to 26.5Hz. According to me, 26.5Hz is the lowest freq that can fit into Amp_Nut's room & the lowest freq that can be accurately reproduced. If 25Hz, 20Hz (both lower than 26.5Hz) do not fit into the room then how can Amp_Nut hear those frequencies???
P.S. we do not have to worry about frequencies higher than 26.5Hz because they all fit into Amp_Nut's room with multiple wavelenghts to spare.

Let's take 20Hz,for example, which has wavelength = 55.8 feet & 1/2 wavelength = 27.9 feet. 27.9 feet does not fit into Amp_Nut's room which has a max dimension of 21 feet. So, what does the 20Hz wave look like in Amp_Nut's room??? Let's assume a pure sinusoid 20Hz waveform JUST for the sake of argument: 21 feet of the 27.9 feet 1/2 wavelength fits into the room & then what happens to the (27.9-21=6.9 feet)? According to my thinking, the remainder 6.9 feet, after it has hit the wall, has to wrap itself back/fold back onto the wave. After the wave has hit the wall, there is BOUND to be a phase-shift. So, now the remainder waveform folding back onto the original wave has different phase shift than the original. This different phase-shift of the reflected partial 20Hz wave will add/subtract from the original partial 20Hz wave & there is bound to be some/a lot of smearing of the sound/sonics. According to my thinking, Amp_Nut is not going to hear a crisp, clean 20Hz wave in his room of the aforementioned dimensions.
I also think that depending upon how much folding of the waveform there is, the smearing could be not bad/bad/very bad. And, depending upon the smearing, the listner could hear the frequency quite well/OK-OK/not at all.

And, I *think* that Square_wave is referring to this aspect as the accuracy of the waveform reproduced in a room of a certain size.
OR, am I off-track here?????

A couple of comments.

The first is trivial : The room size mentioned by me is Not my room. Its just a set of dimensions I thought were reasonable.

If the bass freq wave cannot fit into the room then how can one hear it???

Just an empirical observation... The passenger compartment of a car is Tiny compared to even small rooms, yet pretty deep bass can be created in that space ?

bombaywalla schrieb:

square_wave schrieb: Amp_Nut schrieb: Hope that this answers your question. FWIW Infact, the conclusion I was pushing towards was that room dimensions DO NOT determine the lowest freq of bass that can be reproduced in a room. But it determines how accurately it reproduces it. Amp_Nut, SQ & other members, I have been thinking about this also. I read the same info back when I was tuning my room w/ the ASC TubeTraps & took the info by the stalwarts to be the gospel truth. My main aim was to tune out the resonances in my room & not really care about the lowest freq reproducable. Now, thanx to Amp_Nut, this matter has been resurrected for me. If the bass freq wave cannot fit into the room then how can one hear it??? Let's take Amp_Nut's room (as he has graciously provided the dimensions earlier). The diagonal along the floor calculates to 19+ feet, which xlates to some 29.3Hz. And, if you take the diagonal from one corner on the floor to the opposite corner on the ceiling then that calculates to some 21 feet, which xlates to 26.5Hz. According to me, 26.5Hz is the lowest freq that can fit into Amp_Nut's room & the lowest freq that can be accurately reproduced. If 25Hz, 20Hz (both lower than 26.5Hz) do not fit into the room then how can Amp_Nut hear those frequencies??? P.S. we do not have to worry about frequencies higher than 26.5Hz because they all fit into Amp_Nut's room with multiple wavelenghts to spare. Let's take 20Hz,for example, which has wavelength = 55.8 feet & 1/2 wavelength = 27.9 feet. 27.9 feet does not fit into Amp_Nut's room which has a max dimension of 21 feet. So, what does the 20Hz wave look like in Amp_Nut's room??? Let's assume a pure sinusoid 20Hz waveform JUST for the sake of argument: 21 feet of the 27.9 feet 1/2 wavelength fits into the room & then what happens to the (27.9-21=6.9 feet)? According to my thinking, the remainder 6.9 feet, after it has hit the wall, has to wrap itself back/fold back onto the wave. After the wave has hit the wall, there is BOUND to be a phase-shift. So, now the remainder waveform folding back onto the original wave has different phase shift than the original. This different phase-shift of the reflected partial 20Hz wave will add/subtract from the original partial 20Hz wave & there is bound to be some/a lot of smearing of the sound/sonics. According to my thinking, Amp_Nut is not going to hear a crisp, clean 20Hz wave in his room of the aforementioned dimensions. I also think that depending upon how much folding of the waveform there is, the smearing could be not bad/bad/very bad. And, depending upon the smearing, the listner could hear the frequency quite well/OK-OK/not at all. And, I *think* that Square_wave is referring to this aspect as the accuracy of the waveform reproduced in a room of a certain size. OR, am I off-track here?????

I don't think I could have said it better

Amp_Nut schrieb:

A couple of comments. The first is trivial : The room size mentioned by me is Not my room. Its just a set of dimensions I thought were reasonable. If the bass freq wave cannot fit into the room then how can one hear it??? Just an empirical observation... The passenger compartment of a car is Tiny compared to even small rooms, yet pretty deep bass can be created in that space ? :)

Deep bass. But is it accurate bass ?
I always wondered how active DSP works to overcome this problem in smaller rooms and cars.
For example:
Tact gear
Very successful use of dsp by the Emerald physics guys using the behringer gear.

Interesting views Bombaywalla. Well, not everyone subscribes to the view that if the bass frequency wave cannot fit into the room then one cannot hear it accurately, including Sennheiser who makes the HD800 headphone that has a flat frequency response that goes down to 14Hz. I have used such headphones while traveling in the passenger seat of a car, and they accurately reproduce very low frequencies whose wavelengths or half wavelengths easily exceed the size of the car.

DSP cannot do magic and reshape waves accurately or fix each and every problem. Depending on the speaker - room interaction and how the DSP is programmed to deal with it, the DSP can provide filters to notch out modes / nodes and large peaks that interfere with other frequency bands thus cleaning up the damage to the extent that is possible. It can also do some equalization if the speaker response is not flat and needs to be equalized. I have seen some fantastic DSP implementation in Genelec DSP loudspeaker systems. They have used the DSP there very cleverly to clean up the damage caused by speaker - room interaction, with very good results.

@jsa_ind,
When it comes to headphones, isn’t volume an issue ? The sound just does not go out into the surroundings to create the damage.

No pre-defined formula can predict how a room will respond to a hifi setup. You need to actually play it in a room, measure and then ..... (in my opinion)...leave it alone

Well ofcouse, i'm assuming the room is relatively large.

If you have a smaller room, you will resort to room acoustic treatment...which is just a "analog" equializer


With respect to power...i'm more than happy with 60 watts being pumped into speaker which is 88db SPL in room that is 18x27 feet in size (listening distance of about 12-15 feet) Again, i do not agree with this forumla.

Audio is Chaos...no "single" forumla can ever predict room and acoustical behaviour of a room. There are just too many parameters.

Do all these calculations also hold good if the configurations is corner placement ie speakers firing down a diagonal of the room ?

Arj schrieb:

Do all these calculations also hold good if the configurations is corner placement ie speakers firing down a diagonal of the room ?

Arj, I believe that it does since the article does not specify where the stereo is physically placed. The article addresses SPL output vs. amplifier wattage. Like I wrote in my #1 post: it does not consider speaker impedance vs. freq nor the interaction of the speakers w/ the room.

square_wave schrieb:

@jsa_ind, When it comes to headphones, isn’t volume an issue ? The sound just does not go out into the surroundings to create the damage.

Volume is amplitude. Wavelength whether low in amplitude or high in amplitude stays the same of a given frequency. So if the wavelength of say 15hz reproduced by a speaker needs to fit in the room ( which would have to be approx 23 meters long if it has to be the size of one full cycle), how would u describe the working of this phenomenon when a Sennheiser HD800 open circumaural headphone reproduces the same 15Hz frequency. When using such open circumaural headphones, one can pretty clearly hear the people seated in the car next to you talking, and they can also faintly hear the sound played from the HD800. So in which space does this 15Hz from the headphone gotta fit into, for it to be reproduced accurately into the ears of the user of the headphone?

I can only add to this post by saying that there is never a term "more than enough power". There is never enough! This was told to me very early on in my Audio career by a old
/oiled dealer in Singapore. "Old chinese proverb" Ha!

SWITCH-IT-ON schrieb:

I can only add to this post by saying that there is never a term "more than enough power". There is never enough! This was told to me very early on in my Audio career by a old /oiled dealer in Singapore. "Old chinese proverb" Ha!

I agree & am beginning to see this in my own system as I have changed equipment over the years. You *think* that you have sufficient power & that the music sounds just right & then you try a higher wattage amplifier & the music takes on a totally different meaning! Wow! You just thought that you had enough power.......
I think this is the philosophy of Anthony Michaelson of Musical Fidelity - he's one of the few making large wattage amps & continues to do so.
The key to *any* large wattage amp is to make it sound like real music. The implementation separates the men from the boys IMO. There are plenty of bad sounding large wattage amps out there that drive people to lower wattage amps.

Bombaywalla

High power is very commonly mistaken to be better and many manufacturers play that card, no offense and ruin the presentation. Its like saying all the ills in a car can be fixed with a large engine ! Not so !

I am the one driven to lower wattage amps only becuase I value the melody, sweetness, delicacy and nimbleness with which certain music I listen to needs to be portrayed with and some big amps just don't do it. Sad but true.

I remember we discussing this a long time ago....the inherent merits of low wattage amps v/s the behemoths and vice versa.....


Manek

Manek schrieb:

Bombaywalla High power is very commonly mistaken to be better and many manufacturers play that card, no offense and ruin the presentation. Its like saying all the ills in a car can be fixed with a large engine ! Not so ! I am the one driven to lower wattage amps only becuase I value the melody, sweetness, delicacy and nimbleness with which certain music I listen to needs to be portrayed with and some big amps just don't do it. Sad but true. I remember we discussing this a long time ago....the inherent merits of low wattage amps v/s the behemoths and vice versa..... Manek

True, Manek, we discussed this topic many moons ago.
There ARE some large wattage amps that sound excellent & they are very, very few & far between & they ARE expensive! No surprise, no?? The key is finding & affording these large wattage amps. They do light up the music in a totally different, realistic way that no lower wattage amp has been able to for me.
Since so many bad sounding large wattage amps exist in the market that are more affordable by the public, the probability that one would have a bad experience w/ a large wattage amp is very, very high. That would, no doubt, cause the listener to make the same conclusion as you have.

wise men - does it have to do with distortion & head room ?
Lower the distortion & greater the head room is 'generally' better ?
Is it not about the 'quality' rather than the 'quantity' ?
Besides - speaker 'load' & 'sensitivity' too would play a major role in the kind of amplifier one should 'choose' !
Just my 2 cents worth...

True....you have a point bhagwan.

Quality too is subjective....certain people look at certain qualities in an amp like headroom, etc and some dwell on others....

But easy to drive speakers incl high sensitivity spkrs could well increase the choice of amps that fit ones tastes/system and power may not be so much of a consideration after all.

Manek

bhagwan69 schrieb:

Besides - speaker 'load' & 'sensitivity' too would play a major role in the kind of amplifier one should 'choose' ! Just my 2 cents worth... :L

my cents are also in your cup ie in the end the amp should have more juice than the speaker can hold at All frequencies..after that it is all unused power. and that is very speaker specific.. i doubt if a 98 DB speaker at 8 ohms all the way down would be able to differentaite between identical 30W or 100W amps.

But considering that not many speakers and almost no amps does give out their response curves things get rather vague

I believe power certainly does improve the bass because of more control on the woofer and from what I understand it results in an improved midrange especially in 2 way or 2&1/2 way speakers as the bass and midrange drivers are common. But how much power is enough and how much is More is definitely speaker specific.

Gentlemen, glad to have you all on-board! I note that all of you are basically saying the same thing as Square_wave & myself - just using different words.

Besides - speaker 'load' & 'sensitivity' too would play a major role in the kind of amplifier one should 'choose' !

But how much power is enough and how much is More is definitely speaker specific.

IMO, correct & correct!
The article I gave a link to should be taken at face-value for the info that it provides. Like I wrote 2 times before, one needs to take into account the specific speaker & the room acoustics.

i doubt if a 98 DB speaker at 8 ohms all the way down would be able to differentaite between identical 30W or 100W amps.

Given the products that actually exist in the market & the long history of audio from the 1960s onwards I would unhesitatingly say that 30W/ch amps are not made the same way as 100W/ch amps.
Maybe, just maybe the Sugden is an exception (Arj you can shed more light on this one) in that a 25W/ch amp is made to power difficult loads????
I have a 30W/ch vintage amp & that amp sounds very beautiful sonically but it has only 2 transistors for push & 2 for pull. What is the capability of that amp to drive a difficult load?? Very low capability - my research has shown that my 30W/ch vintage amp handles 6-8 Ohm load speakers the best & at 4 Ohms it's running out of gas. No surprise. I, myself, have 8 Ohms speakers hence the amp is not stressed in my system at all. Just FYI.
OTOH, a 100W/ch amp has many more output transistors & can drive a difficult load much better.
So, this shows up in better speaker control.
Unless you spend a great deal of money (I'm thinking Accuphase here) you are not going to get an

identical

30W & 100W amp realistically. Thus, yeah, the 98dB speaker will distinguish the 30W & 100W amp. IMO.

BTW, using the info in the article I provided the link to, a 98dB speaker would need ~40W/ch to produce 105dB SPL peaks in a room. One would probably use 1/10th that power for listening with the rest, as Arj wrote, is all unused power sitting there for headroom (as Bhagwan69 wrote). And, it is panning out pretty much like what Manek wrote:

But easy to drive speakers incl high sensitivity spkrs could well increase the choice of amps that fit ones tastes/system and power may not be so much of a consideration after all

So, the calculations do pan out correctly per that article. The article lands you in the correct ballpark w.r.t. amplifier wattage needed. You take that info, add to that the specific speaker + the room acoustics & now you should have plenty of info to target the correct amplifier for the job.

bombaywalla schrieb:

Given the products that actually exist in the market & the long history of audio from the 1960s onwards I would unhesitatingly say that 30W/ch amps are not made the same way as 100W/ch amps. Maybe, just maybe the Sugden is an exception (Arj you can shed more light on this one) in that a 25W/ch amp is made to power difficult loads????

Exactly the reason i mentioned the same amplifier design..in order to compare power, it has to be made design agnostic and hence assume it to be the same. using the accuphase A series example i guess we could assume it to be a comparison between an A30 and an A60.

But i Agree we are all talking quite the similar points here but with different view points

I wonder why there has been litle mention of the Reactive Load of speakers....

Can make a 100 Watt 'Tiger' amp into a 50 Watt 'Pussy'

Correct ! But fortunately my pack of spkrs aren't known to make pussy's out of tigers !

And given the average room sizes in mumbai the tiger turned pussy also pulls through many a times.

Manek

The Tiger Turned Pussy amps usually do not manifest their short comings in low SPLs ( Sound Pressure levels ) because the highly reactive loads appear at certain frequencies only, with the most significant changes in the Bass or ( as for some electrostats ) at treble.

Hence the pussys fail to deliver Bass slam etc, rather than simple 'Volume.'

Improper handling of certain frequency bands will therefore show up even in small Indian rooms, if the ears and rest of the equipment is upto it...

Good Reactive load delivery often manifests itself in a smaller powered amp sounding better than some other amp that may have twice the output power rating.

As Switch-It=On said : You can never have enough of Power ... and Power needs to be 'Good' and 'Genuine.'

No point giving "High Power' a bad name when you are using a poor example as a case study.

Amp_Nut schrieb:

I wonder why there has been litle mention of the Reactive Load of speakers....

Amp_Nut, it has been mentioned several times in my posts.
From my post, #23:

Like I wrote in my #1 post: it does not consider speaker impedance vs. freq nor the interaction of the speakers w/ the room.

from my 1st post (#1):

2nd issue: you DO need to consider the speaker impedance vs. frequency when you select an amplifier (even if it's a brute of an amplifier). The article does not address that issue.

Ampnut,
I think bombaywalla is talking about those who are masquerading as high power but are not or they are but the presentation is quite so so.

Now I had this experience last year wherein I heard an amp 80 watts a side, dual mono, supposedly oversized power supply. It sang like a bird at normal listening level but that presentation took a nasty turn once turned up. Lost the staging, bass control, refinement in th mids and highs. When I asked for the price and I got an obnoxious amount. Tried another piece of the same model and the same pitfalls. Tried another brand with similar power ratings, and the presentation was composed even at very high volumes but no cigar on the musicality across the power band.

Now to me this was a case of not so genuine watts above a certain limit and it also turned from a gracefull tiger into a agressive pussycat.

So a case for both situations, bad at high volume and genuine at normal listening levels. If the listening room wasn't treated heavily with absorbent material then could this amp have just passed the audition?

Just my experience.

Manek

jsa_ind schrieb:

square_wave schrieb: @jsa_ind, When it comes to headphones, isn’t volume an issue ? The sound just does not go out into the surroundings to create the damage. Volume is amplitude. Wavelength whether low in amplitude or high in amplitude stays the same of a given frequency. So if the wavelength of say 15hz reproduced by a speaker needs to fit in the room ( which would have to be approx 23 meters long if it has to be the size of one full cycle), how would u describe the working of this phenomenon when a Sennheiser HD800 open circumaural headphone reproduces the same 15Hz frequency. When using such open circumaural headphones, one can pretty clearly hear the people seated in the car next to you talking, and they can also faintly hear the sound played from the HD800. So in which space does this 15Hz from the headphone gotta fit into, for it to be reproduced accurately into the ears of the user of the headphone?

I do not know the principles behind how a headphone produces the illusion of 15 hz in the ear. But I am sure the 2 inch driver in these headphones are surely not reproducing 15 or 20 hz frequencies in the real sense of the word. Such frequencies will move a lot of air and you feel it rather than hearing it much. The effect is very visceral.

square_wave schrieb:

jsa_ind schrieb: square_wave schrieb: @jsa_ind, When it comes to headphones, isn’t volume an issue ? The sound just does not go out into the surroundings to create the damage. Volume is amplitude. Wavelength whether low in amplitude or high in amplitude stays the same of a given frequency. So if the wavelength of say 15hz reproduced by a speaker needs to fit in the room ( which would have to be approx 23 meters long if it has to be the size of one full cycle), how would u describe the working of this phenomenon when a Sennheiser HD800 open circumaural headphone reproduces the same 15Hz frequency. When using such open circumaural headphones, one can pretty clearly hear the people seated in the car next to you talking, and they can also faintly hear the sound played from the HD800. So in which space does this 15Hz from the headphone gotta fit into, for it to be reproduced accurately into the ears of the user of the headphone? I do not know the principles behind how a headphone produces the illusion of 15 hz in the ear. But I am sure the 2 inch driver in these headphones are surely not reproducing 15 or 20 hz frequencies in the real sense of the word. Such frequencies will move a lot of air and you feel it rather than hearing it much. The effect is very visceral.

definitely agree with Square_wave: 15Hz bass is more felt & less heard.
I counter jsa_ind with a question: are speaker manuf like Andy Paynor of Rockport, Martin Logan Statement, B&W, etc stupid to integrate 12", 15" woofers in their speakers to reproduce real low bass when they could have gotten away by using the same driver in the Sennheiser HD800 open circumaural headphone??
jsa_ind, do you realize the amount of air that needs to be moved to reproduce 15Hz bass & the accordingly the wattage needed by the amp to produce a SPL high enough for the listener to hear & feel it???
Do you have an understanding of the challenges involved here??

square_wave schrieb:

I do not know the principles behind how a headphone produces the illusion of 15 hz in the ear. But I am sure the 2 inch driver in these headphones are surely not reproducing 15 or 20 hz frequencies in the real sense of the word. Such frequencies will move a lot of air and you feel it rather than hearing it much. The effect is very visceral.

could it be that it is not the 15 Hz fundamental we ae hearing but a higher harmonic ?

The headphone diaphram does not have to move air in the entire room .... only the air the ear canal.

Moving only the ear canal air for 15 Hz, is notan impossible task.

Yes, the physical impact of deep bass against the body is always missing.... a shortfall in ANY headphone listening.

bombaywalla schrieb:

I counter jsa_ind with a question: are speaker manuf like Andy Paynor of Rockport, Martin Logan Statement, B&W, etc stupid to integrate 12", 15" woofers in their speakers to reproduce real low bass

They are not stupid, but very smart......they are supplying - exactly what many consumers wants

a 12 or 15 inch woofer is required to create LF at pressure levels required in a room...

A headhone diapharam is capable of doing the same in the ear canal.

You dont need a 15 inch woofer to shoot 15 Hz or whatever frequency from 2 or 3 cms away, into a miniscule air volume of the ear canal.

I am also pretty sure that the 15 Hz is a measured Freq.. Certainly not a harmonic .

I suppose the only reason low powered amps are preferred is because it is easier, less expensive, more abundantly available to have high quality low powered amp than a high quality high powered amp....
Saying that a very high sensitive speaker doesnt react to higher powered amps is totally contrary to my experience.

I have auditioned and compared a 98db speaker with amps ranging from 20 watts to 200 watts....and the difference was clearly audible as we went higher up on the power. Yes, the only thing was, even a 20 watter sounded comfortably at home with the speaker...but with the 200 watter music was in a different plane!!! One has to hear them to know what was missing with the 20-40-60 watters we tried.

I totally agree with SWITCH-IT-ON...there is nothing called enough power...

abhi.pani schrieb:

I suppose the only reason low powered amps are preferred is because it is easier, less expensive, more abundantly available to have high quality low powered amp than a high quality high powered amp....

correct!
(altho' I do not understand what you mean by "more abundantly available"??)
I believe that the availability translates directly to cost of manuf & sale pricing i.e. what the user is willing & comfortable paying for the product. And, indeed there are few who'd shell out big bucks for a hi-powered amp even if the hi-powered amp sounded very good.

abhi.pani schrieb:

Saying that a very high sensitive speaker doesnt react to higher powered amps is totally contrary to my experience. I have auditioned and compared a 98db speaker with amps ranging from 20 watts to 200 watts....and the difference was clearly audible as we went higher up on the power. Yes, the only thing was, even a 20 watter sounded comfortably at home with the speaker...but with the 200 watter music was in a different plane!!! One has to hear them to know what was missing with the 20-40-60 watters we tried.

totally agree! I think that a lot of people believe that a high sensitive speaker will provide its best w/ a low wattage amp. More often than not, this is not true! The music takes on another level of emotional experience if the power amp wattage goes up into the 100W/ch or higher, just as you experienced.

abhi.pani schrieb:

I totally agree with SWITCH-IT-ON...there is nothing called enough power...

And, that seems to be Musical Fidelity's motto. I don't care much for M-F products but their crusade certainly seems to be along the lines of higher wattage power amps.

bombaywalla schrieb:

abhi.pani schrieb: I suppose the only reason low powered amps are preferred is because it is easier, less expensive, more abundantly available to have high quality low powered amp than a high quality high powered amp.... correct! (altho' I do not understand what you mean by "more abundantly available"??) I believe that the availability translates directly to cost of manuf & sale pricing i.e. what the user is willing & comfortable paying for the product. And, indeed there are few who'd shell out big bucks for a hi-powered amp even if the hi-powered amp sounded very good. abhi.pani schrieb: Saying that a very high sensitive speaker doesnt react to higher powered amps is totally contrary to my experience. I have auditioned and compared a 98db speaker with amps ranging from 20 watts to 200 watts....and the difference was clearly audible as we went higher up on the power. Yes, the only thing was, even a 20 watter sounded comfortably at home with the speaker...but with the 200 watter music was in a different plane!!! One has to hear them to know what was missing with the 20-40-60 watters we tried. totally agree! I think that a lot of people believe that a high sensitive speaker will provide its best w/ a low wattage amp. More often than not, this is not true! The music takes on another level of emotional experience if the power amp wattage goes up into the 100W/ch or higher, just as you experienced. abhi.pani schrieb: I totally agree with SWITCH-IT-ON...there is nothing called enough power... And, that seems to be Musical Fidelity's motto. I don't care much for M-F products but their crusade certainly seems to be along the lines of higher wattage power amps.

Does this hold true for high sensitivity single driver full range or horns.. ?

I dont have much exposure with Single driver horn loaded speakers...but whatever little I have auditioned, I found them to be very specialized kind of speaker suited for certain kind of music...so I would not be surprised if their amplification requirements are also very specialized .

Why should it be very different for horns or single drivers then ?

Or is it that high power amps kind of make up for inefficient(power sapping,complex) passive crossover networks in certain speakers ? Hence single drivers fair better with lower wattage amps ?

Manek

square_wave schrieb:

bombaywalla schrieb: abhi.pani schrieb: I suppose the only reason low powered amps are preferred is because it is easier, less expensive, more abundantly available to have high quality low powered amp than a high quality high powered amp.... correct! (altho' I do not understand what you mean by "more abundantly available"??) I believe that the availability translates directly to cost of manuf & sale pricing i.e. what the user is willing & comfortable paying for the product. And, indeed there are few who'd shell out big bucks for a hi-powered amp even if the hi-powered amp sounded very good. abhi.pani schrieb: Saying that a very high sensitive speaker doesnt react to higher powered amps is totally contrary to my experience. I have auditioned and compared a 98db speaker with amps ranging from 20 watts to 200 watts....and the difference was clearly audible as we went higher up on the power. Yes, the only thing was, even a 20 watter sounded comfortably at home with the speaker...but with the 200 watter music was in a different plane!!! One has to hear them to know what was missing with the 20-40-60 watters we tried. totally agree! I think that a lot of people believe that a high sensitive speaker will provide its best w/ a low wattage amp. More often than not, this is not true! The music takes on another level of emotional experience if the power amp wattage goes up into the 100W/ch or higher, just as you experienced. abhi.pani schrieb: I totally agree with SWITCH-IT-ON...there is nothing called enough power... And, that seems to be Musical Fidelity's motto. I don't care much for M-F products but their crusade certainly seems to be along the lines of higher wattage power amps. Does this hold true for high sensitivity single driver full range or horns.. ?

I spoke to a single driver speaker manuf a few weeks ago (I'll keep his name & his company anonymous to protect the innocent) & he told me that all his speakers benefitted tremendously when played with a 100W/ch amp.
(100W/ch might seem to be on the low side, which is true for a speaker that is 88-90dB efficient but for a speaker that is 94dB efficient or higher, 100W/ch is a lot).
When I auditioned those speakers at a dealer's shop, the dealer was playing them with 5W/ch and 8W/ch tube amps. Yes, 5W/ch - I did not make a typo here! The single driver speakers sounded really very, very good. I was totally amazed & it blew my expectations of a single driver speaker. However, that very dealer was dropped/removed by the speaker manuf because the manuf just could not convince that dealer to play the single driver speakers with a 75-100W/ch power amp to really show-off the speaker's capabilities!
The manuf was so convinced that his speakers were getting the short end of the stick at the dealer's shop that he removed that dealer from his network! How's that for conviction that higher powered amps are beneficial to even highly efficient single-driver speakers??

One my friend's once owned a single-driver speaker & played it with a 120W/ch Modjeski RM-9 tube power amp. He loved the overall sound but he sold the speaker because it could not play every genre of music that he owned (what Abhi was alluding to in his post).


I cannot comment intelligibly on power amp requirements for horns as I have minimal experience w/ them.