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Speaker Design & Building What Is It All About ?

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Beitrag
jsa_ind
Stammgast
#1 erstellt: 21. Aug 2005, 21:47
Hi All,

Viren posted a very interesting link http://www.nutshellhifi.com/library/speaker-design1.html With his permission I have initiated this thread.

Quite a few of us on the forum are into hardcore speaker design be it raw drivers or speaker cabinets. A few of us know all about speaker building. Others are interested but don't know how to go about things

Can we share our knowledge and pool our resources ?

Regards,

Junia.

P.S. I am on the road for a week, but I promise to contribute once I am back.


[Beitrag von jsa_ind am 21. Aug 2005, 21:48 bearbeitet]
Manek
Inventar
#2 erstellt: 22. Aug 2005, 04:48
this will get interesting...:-) my kind of post !

Let me start with a question which I have wanted answers for a while now......

If I were to mount a tweeter open, outside the speaker box how would you expect the tweeter to react or behave ? Are there any tweeter loading rules I have to follow like the mid/bass drivers ? Are there only specific tweeters which can be mounted on an open baffle ?

manek.
anirvan
Stammgast
#3 erstellt: 22. Aug 2005, 05:41
hi,
the other day i was at 'cinebels' the jamo store-
saw some speakers with their drivers open-just mounted on a shaped acrylic sheet-
how different would that be-and why such a design in the 1st place-coz all other i ve seen are inside cabinets-

r
anirvan
sivat
Stammgast
#4 erstellt: 22. Aug 2005, 09:34
Manek,

Its a good idea to Move the tweeter out of the cabinet like in B&W Nautilus series. You get to overcome the baffle diffration issue to a large extent and it also helps shielding the tweeter from the standing waves that rattles the inside of the cabinet. From a manufacturing perspective, it also makes it easy to time-align the drivers by moving the tweeter backwards..

I would assume, you can do this with most commercially available tweeters. (A good example is the usher loudspeaker from Taiwan, which is supposed to have been designed by D'Appolito)

Having said this, you need to carefully compute the relative distance between the tweeter and other drivers that constitute the loudspeakers (on X, Y & Z axis)...and this depends on various aspects such as Dispersion, Crossover frequency, etc.,

Cheers
Siva.


[Beitrag von sivat am 22. Aug 2005, 10:48 bearbeitet]
Manek
Inventar
#5 erstellt: 22. Aug 2005, 11:20
Siva,
Sounds more like a win-win situation to me :-)
B&W still load their tweeters with a conical and extended enclosure around the tweeters. Is the enclosure required(except for protection) and if so what does this separate enclosure achieve ? more controlled driver resonance ? does it simulate a horn loading, increasing efficiency ?

Manek.
Sonic_Master
Stammgast
#6 erstellt: 22. Aug 2005, 13:16
excellent explanation from Siva yeah thats why B&W speakers are good at diffraction system. But many dont care about this sorry to say even the highend manufacturers dont follow the diffraction factor. That is one of the reason many find excellent sonic qualities in the B&W highend range speakers

Even the time aligning its very nice so the speaker should be in such flexible that one can change the time alignments coz time alignment using the crossover is possible but very expensive and also not recommended since there will be lots of components in the path.

but I do recommend alot on the diffraction factor while designing and one of my next design includes some excellent diffraction optimizations.

cheers,
Sandeep
sivat
Stammgast
#7 erstellt: 22. Aug 2005, 13:23
The construction of the tweeter itself is a complex subject....one such advanced construction is the B&W's tweeter. This kind of technique has to be adopted at the "driver (tweeter) manufacturing" stage, rather than at "loudspeaker integration"stage. You are correct that this technique would reduce the impact of resonance, provided the manufacturing process incorporates sufficient dampening. However, i have my doubts on SPL .. if anything there would only be an negative impact on SPL due to this technique.

Theroritically, you can apply the same technique to load the mid/bass drivers. In practise, you could probably do this with a few mid ranges drivers....but it might not be practically possible for most mid/bass drivers (due to increased wave length).

While "baffle diffraction" is the primary target for mounting the tweeter this way, the "audible" difference due to baffle diffraction is a very debatable subject.....many folks in the industry say this is a hyped up marketing campaign. Also, when you think about making the manufacturing process in terms of cost effectiveness, this is the last thing you want to do... These are the reasons why you do not see many commercial models with this design.

There are also alternatives to this design from B&W; For example, VIFA uses an "Dual Chamber" approach to lower resonance
benkenobi
Hat sich gelöscht
#8 erstellt: 22. Aug 2005, 14:48

sivat schrieb:


There are also alternatives to this design from B&W; For example, VIFA uses an "Dual Chamber" approach to lower resonance


Could you elucidate on this point Siva n others..
What do u mean by chanmbered and dual chambered?
Cheers,
Sachi


[Beitrag von benkenobi am 22. Aug 2005, 14:49 bearbeitet]
Sonic_Master
Stammgast
#9 erstellt: 22. Aug 2005, 14:55
yes siva can u explain how and what about the concepts of chambered and double chambered drivers... Let me know in depth regarding this ofcourse the resonance is reduced upto some extent but we want to know in depth about this ... any idea about this?

cheers,
Sandeep
viren
Stammgast
#10 erstellt: 23. Aug 2005, 03:50
Hello all,

With all dynamic drivers in enclosures, the purpose of the enclosure is to isolate the sound radiated from the rear of the driver to that from the front, and then to absorb the rear radiation.

With tweeters, the frequency of sound radiated is so high, and the wavelengths so small, that the faceplate of the tweeter itself is large enough to act as a baffle. The rear wave is absorbed in the cavity formed between the diaphragm and the magnet.

Of course, this is not ideal, as cavities have resonances and reflections too, which superimpose themselves on the diapragm. Vifa solves this by providing a dual chamber behind the magnet, into which this rear energy is guided and absorbed in damping material. This alters the acoustic loading on the diaphragm also, and lowers the resonance frequency of the overall assembly.

Bowers and Wilkins take a classic approach in their advanced tweeters. The rear radiation is absorbed in a varying diameter tuned enclosure behind the diaphragm. This takes care of varying resonance modes, and offers a very stable load to the diaphragm. Much lower distortion results!

But Siva is correct in pointing out other issues with moving a tweeter away from other drivers. Just one driver does not a speaker make! Remember, you are trying to simulate a point source. All the drivers have to integrate to make a unified sound. Driver spacing, crossover points, all contribute towards that.

Again, it's worthwhile to reiterate - it's not only the components you use, it's the implementation (the execution of the design) that is of primary importance!

Viren.
benkenobi
Hat sich gelöscht
#11 erstellt: 23. Aug 2005, 04:40
Thanks for that Viren.
Very informative.
one thing though bothers me. in your speakers u asay tath u xover the tweeters at a very high 6-7kHz(which is actually ideal). but won't the driver spacing decrease dramatically if u xover them so high?

How do you counter this?
i mean with my speakers which are xovered at 3.4 kHz asks for a maximum driver spacing between the mids and the tweeter to be 4.1 inch or so but i could not make it so less and have kept it at 5 inches.
Cheers,
Sachi
sivat
Stammgast
#12 erstellt: 23. Aug 2005, 09:43
Just to add to the explanation Viren has already provided....the dual chamber is a technique that is quite popular amoung subwoofer designs.

FYI...i'm travelling from tommorow and will talk to you folks after a week.

Cheers
Siva.
Manek
Inventar
#13 erstellt: 23. Aug 2005, 10:33
Viren....a mid/bass driver extended upto 6-7khz... Ordinarily I would think the sound would get very directional with quite a bit of distortion as well around those frequencies and could cause ear fatigue...how do you circum-navigate these issues ?
On the other hand...the tweeter would be a very relaxed performer.

Manek.
viren
Stammgast
#14 erstellt: 24. Aug 2005, 13:17
Yes, there are many pitfalls with using a driver full range. And some compromises.

To me, the transparency and dynamics that I hear with a direct (crossover-less) connected driver are important enough to compromise on the other issues. Directivity does narrow with frequency, but the reflected energy from the room compensates - and most Indian homes tend to be more on the live side. Distortion does not necessarily go up - these drivers have a very smooth response to the upper midrange; peaks and valleys balance each other out.

Some amount of shaping can be done with just the tweeter crossover - remember, the overlap occurs over an octave, and is shaped by both sides.

Viren.
Manek
Inventar
#15 erstellt: 29. Aug 2005, 13:02
To Viren, siva, junia and all...

Another question....

How does one mate a 6ohm tweeter to a 4 ohm mid bass driver without getting a large impedance dip at cross over region ? My basic understanding of parallel filter theory is that impedances during crossover overlap follow the rule of adding of parallel resistances which would in the above case result in an effective 2.4 ohm impedance which the amp wil see around the crossover region...can you first tell me if this is correct and if so is there a
work-around/trick to make the amp see a higher impedance so as not to put much strain on it ? I also realise that these impedances are dynamic and will change with frequency.

I guess the same problem would be faced by many who use a 4ohm mid/bass driver.

Manek.
viren
Stammgast
#16 erstellt: 07. Sep 2005, 03:16
Manek,

Impedances are complex since they may be resistive, inductive, or capacitative in nature. Actually, they are combinations of all three. They don't follow simple additive, whether in series or parallel, rules, since you are dealing with complex numbers.

When combining drivers in a speaker system, not only are the impedances of the drivers in question, but also the interaction of the crossover components in a passive crossover network. It is impossible to calculate the resulting impedance in a simple way. The only way is to measure the final impedance over frequency. You will be amazed how far off the resulting crossover values can be from a theoretically designed crossover. All because of these complex varying impedances.

There are crossover simulation programs available to simulate these impedances. And they use the processing power of PCs. One such program is CALSOD. But the learning curve is pretty steep.

Viren.
Manek
Inventar
#17 erstellt: 08. Sep 2005, 04:56
tks viren, guess the only way is to build the crossover and find out :-)

What are your thoughts on using full range drivers as extended bass/midrange drivers clubbed with a tweeter to take care of the high end....something like piaring a fostex fe206E fullrange for mid/bass and a tweeter crossed over at 5khz and above..it would be quite similar to what you do with your speakers I guess.

Manek.
benkenobi
Hat sich gelöscht
#18 erstellt: 08. Sep 2005, 06:22
Manek,
do one better by not going for axover and use only the fostex..
they are very good for full range speakers..
a bipole would be great to make..
there are many designs and a seperate section for full range on diyaudio.com
Suggest that u also check out t-linespeakers.com
Cheers,
Sachi
benkenobi
Hat sich gelöscht
#19 erstellt: 08. Sep 2005, 06:23
Manek,
do one better by not going for a xover and use only the fostex..
they are very good for full range speakers..
a bipole would be great to make..
alternatively u can also try using the adire audio CSS full range..
its among the most highly regarded full range speaker and costs about 50-60$(each).
there are many designs and a seperate section for full range on diyaudio.com
Suggest that u also check out t-linespeakers.com
Cheers,
Sachi
Manek
Inventar
#20 erstellt: 08. Sep 2005, 06:37
hi benks...

Actually my uncle and I are on a project to make horns out of fostex...we have identified this one driver fe206E for horn loading. He is the guy who has used lowthers for a while but is not very happy with the "shout" and the fact that the foam surrounds rot every 2 years. Now he has had problems with his voice coils so he is pretty fed up with lowthers.

The fostex drivers we have chosen are said to have a very good bottom end and midrange. If we feel we need cleaner top end we have the option of a tweeter crossed over 3 octaves above the tweeter fs with a first order crossover. This is only contingency.

Yes he is a compulsive DIY'er. As long as I can remember he has not used branded speakers and he is only into folded horns.

Manek.
square_wave
Inventar
#21 erstellt: 08. Sep 2005, 07:06
One good person to check out for single driver horn loaded technologies and its complex problems is Jacob George of rethm loudspeaker technologies. He has been working on it for a while and uses a modified Lowther design for his speakers. He is not on this forum. I don’t know how much free time he has though. He is a very busy architect. He has successfully eliminated the “shout” along with other problems with the Lowther DX4 diver. You could contact him at http://www.rethm.com/
Manek
Inventar
#22 erstellt: 08. Sep 2005, 07:10
yes squarewave, I know. My uncle has spoken to him and so have I briefly a year ago.

Thanks for the info anyways.

Manek.
benkenobi
Hat sich gelöscht
#23 erstellt: 08. Sep 2005, 07:22
Sounds interesting..
do keep us abrest.
Manek
sivat
Stammgast
#24 erstellt: 08. Sep 2005, 08:39
[quote="Manek"]
What are your thoughts on using full range drivers as extended bass/midrange drivers clubbed with a tweeter to take care of the high end....something like piaring a fostex fe206E fullrange for mid/bass and a tweeter crossed over at 5khz and above..it would be quite similar to what you do with your speakers I guess.

quote]

Manek,

You could use a tweeter (you could try one of those "super tweeters" like T90A) and build a crossver - the same way as you do for other speakers. I have heard that 206 is an excellent driver, minus the highs..so this is an good attempt.

On you earlier Question on impedance. The answer is that there no fixed solution....each combination of driver behaves differently, and this behavior further varies based on how they are integrated...so playing around with a simulator like Viren mentioned...plus extensive listening sessions would help in optimizing the crossover.

Aplogies for delay in response...had been away form away from the maddeing B'lore crowd/traffic...in Goa.

Cheers
Siva.
Manek
Inventar
#25 erstellt: 08. Sep 2005, 09:42
you luck guy you....siva.....did you gorge yourself on the wonderfull sea food and the pork and the xacuti preparation ? and the sorpatel and the vindalu and the balchao and the bibinks and the booze ? and all the other sinfull stuff you get there ?

Manek.
Manek
Inventar
#26 erstellt: 08. Sep 2005, 09:47
sorry for getting carried away...(I'm only human) :-)
Ok siva now back to the thread...

yes the T90A was one of the prime candidates and is also mentioned in the fostex site as a combo.

Well...we will put our best foot forward on this :-). Since my uncle is retired he has ample time to work on his horn design.

Manek.
Manek
Inventar
#27 erstellt: 08. Sep 2005, 11:29
Another question for you champoins :

What is your opinion on ported speakers with the ports facing downwards instead of the conventional front and rear ? I know a lot of subs that do it but I'm talking
2-way or 3-way ported designs.

Any experiences ?

Manek.
benkenobi
Hat sich gelöscht
#28 erstellt: 08. Sep 2005, 11:35
down ported would couple the air rushing out with the flooor and could lead to placement problems. But this is a problem with all speakers but witha down port it may become just a bit more harder.
you may end up with a increase in bass but i would personally go for a rear ported one if you have enough room.
Manek
Inventar
#29 erstellt: 08. Sep 2005, 11:47
Benks
To my mind I would think the distance between the port mouth and the floor would be critical but thats just about it. With the correct height from the floor one may be able to get just the right ground enforcement for good bass.

Now there is a theory going around that if the port tuning is under 50hz then it doesnt really matter if its rear/front or bottom....how would you take to that ?

Manek.
Manek
Inventar
#30 erstellt: 08. Sep 2005, 11:53
or for that matter ports facing sideways...????
whay does it only have to be rear or front ???

manek.
benkenobi
Hat sich gelöscht
#31 erstellt: 08. Sep 2005, 11:59
Yeah it can be sideways too...
i have heard about this thing about ports tuned below 50Hz.Frankly, have'nt read about it exclusively in any forum but the reason could be more mids being spewed out of the ports and thus muddling the image.
there is no hard and fast rule that the port has to be placed in the front or in the back..
only that the distance of the port from the woofer should be within some criteria which depends on the tunign frequency..
but it is usually so haih(?more than 4-5 feet at least) u can place it any which way you like but don't take my word for it.
Cheers,
Sachi
Manek
Inventar
#32 erstellt: 08. Sep 2005, 12:27
been reading the same .....but if woofers can be side mounted nowadays with good effect I'm sure the ports can too.

About muddying the mids or the image I really wonder how much does the output of the port contribute to a stronger image ? The frequencies out of the rear port would be out of time and phase with the main drivers and if I am right the frequencies at tuning frequency and below are again 180deg of phase(if not out of time as well) so how much do the existing common port orientations of front and rear contribute towards a stable image ? I wonder.

Manek.
viren
Stammgast
#33 erstellt: 08. Sep 2005, 16:04
Hi,

You are correct about the placement of the port not making any difference at low frequencies. Say, at 40 Hz, the wavelength of sound is about 28 ft, with a half-wavelength being 14 ft. The 2 ft. or so depth of the speaker cabinet is of no consequence, and the bass frequencies will get reflected from room boundaries in a similar manner.

There are port pipe resonances higher in frequency, which can be heard. Problems usually occur if the port size is too small, and the high velocity of air makes chuffing noises.

Having the port facing downwards actually gives better coupling to the floor, with a higher output of reflected bass. However, the spacing between the speaker cabinet and the floor becomes critical - it's almost as if it's an extension of the port.

Viren.
Manek
Inventar
#34 erstellt: 09. Sep 2005, 06:35
hi viren,
have you tried out the downward firing port orientation in your experiments ? If so what were your findings ?

Has anyone tried this orientation ?

Manek.
sivat
Stammgast
#35 erstellt: 09. Sep 2005, 08:19

Manek schrieb:
you luck guy you....siva.....did you gorge yourself on the wonderfull sea food and the pork and the xacuti preparation ? and the sorpatel and the vindalu and the balchao and the bibinks and the booze ? and all the other sinfull stuff you get there ?



Yes i did....just lived on sea food. Coming from Panjim, Bangalore traffic looks so un-civilised !!. Wish i could spend more time there....may be we need to organize a week long audiophile conference there ... some excuse to get there ;-)

Wish you and your uncle the very best for your project.

Bottom port : Infact I have seen a proac in such a configuration at Prithvi's place...it sounded quite nice...without any muddiness. Many people feel, that ports at the bottom are easy to "place" compared to rear ported ones.

High frequenency travel almost in a straight line and as we go down the frequency spectrum, the frequencies tends to "spread out" more and more....until frequencies below 100 Hz have almost "no sense" of direction. This is the reason why you could have a sub woofer separately....and on the same principle, you could also put the port in the side....in theory. However, it is the reflection from the traditional "rectangular" room (especially the 90 degree corners and edges), that cause the problem.....and these various port configurations are an attempt to make the speakers more easy to "place". A particular port config might work in your room, and some might not !!. The manufacturers walk a tight rope here as they make thier choice on this aspect...it is more or less a gamble !

Cheers
Siva
Manek
Inventar
#36 erstellt: 09. Sep 2005, 08:30
hmmm....
Siva, Methinks the proac you refer to would be the D25. I havent read of many speakers on the net with a downward firing port except for a few subs. Now that should make it a deterrent but somehow I am not so convinced it would be that bad. Or maybe most manufacturers do not like to tread on road less traveled.

I read sometime back of another DIY guy on the internet who had aped an Avalon speaker with a downfiring port and it worked well for him. Avalon themselves have a couple of speakers I believe with down firing ports and subs. I'm sure there would be other few designs as well(just more difficult to track).

I'm going to research this a bit more.

Manek.
deaf
Stammgast
#37 erstellt: 20. Sep 2005, 10:16
Avalon speakers do not use a tuned port as specified by theile-small parameters.They infact work way beyond normal box design thought processes.The Eidilon diamond uses a custom woofer with an extremely high force factor,designs a sealed enclosure critically damped (i.e.Qt is 0.5), which in their case must be close to 36hz-38hz as the target Fb.The really complex part is then making a vent in this enclosure half an octave below said sealed box Fb that is tuned to 18hz- 19hz,and controlling the resulting complex vent/box impedence behavior with an advanced conjugate network in parallel with the entire speaker system.
As always, easier said than done, which is a very important thing to remember.
SUB_BOSS
Gesperrt
#38 erstellt: 21. Sep 2005, 06:09
Sivat wrote :


Yes i did....just lived on sea food. Coming from Panjim, Bangalore traffic looks so un-civilised !!. Wish i could spend more time there....may be we need to organize a week long audiophile conference there ... some excuse to get there ;-)


hey thats a lovely idea and how about some abroad trips too....

manek.....manek...manek tik tik tik is Hifi forum listening..tik tik ..tik any sponsors for members for week long audiophile conference from forum moderators...
Manek
Inventar
#39 erstellt: 21. Sep 2005, 07:22
heh heh...dream on my friend...Dream On !

manek.
jsa_ind
Stammgast
#40 erstellt: 24. Sep 2005, 00:39
Hey Guys,

I have decided to go ahead & build a reference loudspeaker active system for my Bangalore house.

Can anyone advise me if they have come across a better

Ionic super tweeter than the Acapella Ion TW 1S ...http://www.acapella.de/german/ ?

Midrange than the Reps 1 http://www.rlacoustique.com/reps1.htm

Woofer than Goliath http://www.shadowworks.co.uk/SW/HTML/products/goliath.htm

The combination is per side one Acapella, two Rep 1 in an isobaric combination and eight woofers, two in series, two in parallel in an isobaric combination. with a 18 inch passive radiator

All advice is welcome !

Regards,

Junia.
benkenobi
Hat sich gelöscht
#41 erstellt: 24. Sep 2005, 03:14

jsa_ind schrieb:
Hey Guys,

I have decided to go ahead & build a reference loudspeaker active system for my Bangalore house.

Can anyone advise me if they have come across a better

Ionic super tweeter than the Acapella Ion TW 1S ...http://www.acapella.de/german/ ?

Midrange than the Reps 1 http://www.rlacoustique.com/reps1.htm

Woofer than Goliath http://www.shadowworks.co.uk/SW/HTML/products/goliath.htm

The combination is per side one Acapella, two Rep 1 in an isobaric combination and eight woofers, two in series, two in parallel in an isobaric combination. with a 18 inch passive radiator

All advice is welcome !

Regards,

Junia.

You've got to be kidding me..?

This is going to be epic!
nothing better than the Acapella Ion tweeter.
benkenobi
Hat sich gelöscht
#42 erstellt: 24. Sep 2005, 03:22
What happened to the Dynaudio driver based project?

With that many drivers me thinks this could hit way lower than 20 Hz if executed well with prodigious amounts of SPL.
jsa_ind
Stammgast
#43 erstellt: 24. Sep 2005, 09:04
Dear Sachi,

While the Dynaudio drivers are good they were relevant to me years ago ! Yes 24W100, 17W75 & matched Esotor tweeters along with Passive radiators are an excellent choice, however I thought if I was putting in Reference 250 Plinius monoblocks along with some decent tubes for the mid & highs in an active setup, why not go in for the very best of the best drivers and build a life long investment. Moreover Prestige Exotica has got a huge drawing room, I think it is 30 X 20..... just the room to put in a really good system with some stunning results !

I will probably dispose the Dynaudio drivers when I come in Jan.

Regards,

Junia.
benkenobi
Hat sich gelöscht
#44 erstellt: 24. Sep 2005, 10:51
You've got a point there....
u failed to mention the passive radiator that you would be using
jsa_ind
Stammgast
#45 erstellt: 24. Sep 2005, 12:12
Dear Sachi,

The Passive Radiator is the 18 inch Stryke
http://www.acoustic-...diators/stryke_pr18/

About the midrange what is your suggestion is reps1 a better choice http://www.rlacoustique.com/reps1.htm or
the KM30Sag http://www.phy-hp.com/English/Products/KM30_SAG_E.html in front & the H30ib15_sag http://www.phy-hp.com/English/Products/H30lb15_SAG_E.html in the rear ?

My concern was in an Isobaric combination, for the second combination the T/S is the same minus the high frequency concentric tweeter. While in the reps1 I cannot have that luxury.

I wouldn't want figh frequency bouncing around in the Isobaric tube, it might muddie the sound....what are your thoughts ?

Regards,

Junia.
benkenobi
Hat sich gelöscht
#46 erstellt: 24. Sep 2005, 12:37
Dear Junia, the RSP would need to be cut off at around 6-7 kZ.. from theree the Ion tweeter would take ove..
of course you can xover the mid range higher..but like u say...there would be high frequency waves bouncing off iside the isobaric chamber.
The RSP in theory would perform better but eh PHy looks compelling too.
The Phy without the tweeter is good enough since you would use the ion tweeter..unless of course u plan to use the ion tweeter as a super tweeter(understand it goes upto 50 KHz) and over the PHy higher.
The bass/midbass units freq respoonse in the two PHys are identical..
so u would have to make a call as to what freq u want the Acapella tweeter to take over.

And regarding the Stryke audio passive radiator..that's totally insabe..
Fs below 3 Hz and xmax of 76 mm...
wooo can't wait to see thsoe in action.


[Beitrag von benkenobi am 24. Sep 2005, 12:38 bearbeitet]
jsa_ind
Stammgast
#47 erstellt: 24. Sep 2005, 13:23
Dear Sachi,

Yeah I am going to enjoy building this system up and than coupling it with the DCS gear. It would be interesting to see how low it could go in a real world situation !

Do you know or can you find out if the RSP is a duel concentric or a whizzer cone type ? I know for sure the Ph's are duel concentric. Once I know that it would help in the decision process.

The other concern is a foam surround in Bangalore do they last or not ? I know in Bombay they give way after some time.

Did I share about the crossover Sachi ? Have a look at http://www.deqx.com/index.html it takes most of the guess work out off cross over designing ! It is programmable too and takes care of Phase & time alignment. So all one has to do is set it up do a crossover frequency & slope steepness trials by ear & with MLSSA , input one's Fletcher-Munson Curves, run the software and you are good to go !

So with Linear X I could get the box design going fine tune it with MLSSA and we have a grown up toy !

Regards,

Junia.
deaf
Stammgast
#48 erstellt: 24. Sep 2005, 13:35

benkenobi schrieb:
Dear Junia, the RSP would need to be cut off at around 6-7 kZ.. from theree the Ion tweeter would take ove..
of course you can xover the mid range higher..but like u say...there would be high frequency waves bouncing off iside the isobaric chamber.
The RSP in theory would perform better but eh PHy looks compelling too.
The Phy without the tweeter is good enough since you would use the ion tweeter..unless of course u plan to use the ion tweeter as a super tweeter(understand it goes upto 50 KHz) and over the PHy higher.
The bass/midbass units freq respoonse in the two PHys are identical..
so u would have to make a call as to what freq u want the Acapella tweeter to take over.

And regarding the Stryke audio passive radiator..that's totally insabe..
Fs below 3 Hz and xmax of 76 mm...
wooo can't wait to see thsoe in action.


Dear Ben and Junia ,ever hear the Acapella?Properly.If you haven't,I think you should before you decide on this choice of driver.
Hey Junia what what happened to Dynaudio?No more the best I guess.BTW did you know Acapella is the only other manufacturer besides Dynaudio to use the 2" Esotar midrange dome?In the midrange horn dude,thats where it is.Even then, with the horn acceleration that dome has a hard time keeping up with the tweeter, its that fast.
BTW just using the best drivers, especially with varying technologies does not end up being the best loudspeaker, it will probably end up being the worst,because an instrument with a wide range like a grand piano, will end up sounding like three different instruments between decade to decade.
Hey Benks you sound like a young engineer to me, right?
Just visualise how many times the plasma flame will change its pulse before that radiator will finish its 76mm xmax,then you will think differently.Driver integration is the key,acoustically and tonally.Even with the most sophisticated digital filtering, you cannot change the mechanical and material related tonal properties of a driver, hence the statement loudspeaker designing is a 'science and art'
Regards.
jsa_ind
Stammgast
#49 erstellt: 24. Sep 2005, 13:40
Welcome Deaf...it is nice to pick someone's brains at last !

Junia.
deaf
Stammgast
#50 erstellt: 24. Sep 2005, 13:53
Junia the Canadian speaker has a whizzer and the French one is a coaxial in its most expensive iteration.NEITHER DRIVER IS A DUAL CONCENTRIC, WHICH HAS A FUNDAMENTAL DIFFERENCE FROM A COAXIAL
Regards
jsa_ind
Stammgast
#51 erstellt: 24. Sep 2005, 14:07
Dear Deaf,

I should be asking you the question have you heard the Acapella with a woofer in a passive radiator combination I have........ and it sounds out of the world that is how I decided to do what I am doing right now !

What make you say that I believe that Dynaudio was the best ? It does not mean just because I have the Dynaudio Evidence Master I endorse that it is the best ! Either you have been misinformed or you haven't been reading my previous posts properly !

Well, haven't you heard of cases where you used the best ingredients & come up with the best dish ? It is all in the recipe my friend and the courage to go where other fear to tread ! The mere fact that the Ionic tweeters are sold as stand alones is demonstration that integration with other drivers is alive & well on planet earth !

Are you into speaker designing ? Would you be able to advise on the audio tools you use ? Perhaps you could teach us all a trick or two my friend...or like the so called 3 subwoofer theory you would shy away in fear that your commercial interests are going to be hurt ?? Come on I am a so called Commercial Member and there are a whole lot of Commercial Members on this forum who freely share their knowledge without having the insecurity that their means of livelihood are threatened ! Off course if you feel insecure than by all means refrain from sharing any of your experiences...gosh how can you...you are losing valuable money !

Where are you based my friend ? Your profile seems to be strangely veiled ? I can see you love XLR CD's...good for you !

Just because the passive radiator is capable of doing a 76 mm X max does not mean for every cycle it is going at 76 mm !! ......see there is difference between practical & theory & only hear say !

Why the Plasma tweeter even a ordinary tweeter moves faster than the woofer, do you mean to say integration does not & cannot take place with the other speaker drivers ? There are more two way & three ways speaker enclosures in the world than full range &/or duel concentric speakers ! You are way out on a limb my friend !

And please let us continue the worth while debate I seem to have run out of partners of late !

Regards,

Junia.


[Beitrag von jsa_ind am 24. Sep 2005, 14:30 bearbeitet]
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