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Old 22nd December 2004, 09:44 PM   #11
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Default Re: Re: Some rambeling thoughs on Speaker design issues (part 1)

Konnichiwa,

Quote:
Originally posted by 454Casull
Just curious - is your name Thorsten Loesch?
In other places? Yes. Here I am the evil Kuei Yang Wang.

Sayonara
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Old 22nd December 2004, 10:46 PM   #12
Bricolo is offline Bricolo  France
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Hi,

I'm too tired to read the whole topic now but I've read the part1
You mentionned tone perception, and harmonics. This reminded me of a question I wanted to ask: imagine the same tone (the fundamental) played by different instruments.

What makes you recognize a trumpet, a piano, and a guitar? Is it the "spectrum" of harmonics?
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Just remember: in theory there's no difference between theory and practice. But in practice it usually is quite a bit difference... Bob Pease
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Old 22nd December 2004, 10:51 PM   #13
Greg B is offline Greg B  United States
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My only comment is that "*** forwards" is bass ackwards.

Don't you know how to speak english in england?

GB
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Old 22nd December 2004, 11:08 PM   #14
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Konnichiwa,

Quote:
Originally posted by Bricolo
You mentionned tone perception, and harmonics. This reminded me of a question I wanted to ask: imagine the same tone (the fundamental) played by different instruments.

What makes you recognize a trumpet, a piano, and a guitar? Is it the "spectrum" of harmonics?
One of the key makers of the instruments "tone" is indeed the harmonic distribution in SPECIFIC regions, namely the often invoked by me "formant" region. There are other issues too, such as the envelope (attack and decay of a note) and the actual material the instrument is made from adding "parasitic" resonances and so on, hence the overtone (harmonic) spectrum is not all.

But you can experiment with old analog sythesizers and start from the totally dead sounding pure sinewave and then add overtones one by one in varying levels and achieve something that sounds pretty much alike to certain instruments, simply by using the right overtones and attack/decay settings..

Sayonara
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Old 23rd December 2004, 02:04 AM   #15
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So can someone who understands a heck of a lot more about speaker design (& KYW's ramblings) tell me what DIY (or commercial) speaker design comes closest to what KYW suggests as being optimum?

Does the Basszilla have it backwards?

What full range driver would work best?
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Old 23rd December 2004, 05:21 AM   #16
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Quote:
Originally posted by loudandclear
So can someone who understands a heck of a lot more about speaker design (& KYW's ramblings) tell me what DIY (or commercial) speaker design comes closest to what KYW suggests as being optimum?

Does the Basszilla have it backwards?

What full range driver would work best?
I probably understand a heck of a lot less about speaker design than you do, but I've been following KYW's essays on the board for a while and knew what search terms to use. There's nothing that answers your questions directly, but there's enough info to get a pretty good picture of what he has in mind. I hope I will be forgiven for linking all this stuff out of context.

- general description of an "all out" design:
http://www.diyaudio.com/forums/showt...346#post410346

- general description of a scaled-down domestic alternative:
http://www.diyaudio.com/forums/showt...257#post413257

- another essay that states many of the same ideas as this current thread:
Room Acoustics & Speakers - woz: Is15 inch overkill for music?????experts

As I understand it, the basic idea is this:

- a boxed "superwoofer" below the modal frequency of the room, which might be around 40 - 60 Hz (to give a very rough idea), going as low as you can manage
- dipole woofer(s) from there up to 150-300 Hz
- coaxial main array from there on up, with a large (pro?) mid in dipole configuration, with fabric or batting or something to soak up the frequencies much above 300 out back.
- optional supertweeter depending on your mid/high solution

I probably misstated something, so go read the threads.
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Old 23rd December 2004, 11:49 AM   #17
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Konnichiwa,

Quote:
Originally posted by loudandclear
So can someone who understands a heck of a lot more about speaker design (& KYW's ramblings) tell me what DIY (or commercial) speaker design comes closest to what KYW suggests as being optimum?
Well, my suggestions offer a few options:

1) Cone Driver & Fronthorn (eg Oris 150 & AER Driver) combined with a large (maybe Column design like this picture) active dipole woofer and a sealed box type subwoofer.

Click the image to open in full size.

If we (say) use 3pcs 12" Pro-Audio Woofers with a resonance around 40Hz and a Qt around 0.7 we require very little EQ to get a Woofer Array with > 100db/W/m sensitivity at 100Hz and a 40Hz -3db point. Add to this a sealed box subwoofer with (say) a high output extreme woofer (12" XLS with dual passive radiator maybe) crossed over with a suitable LPF and EQ you have a fairly nice system managing realistic SPL's, controlled directivity and so on.

2) Open Baffle with a large dipole woofer (21") and a suitable 8" Fullrange Driver (Supravox and Phy Hp come to mind) or something larger, like for example an array of Ribbon and two 10" wideband woofers or even a "pseudo coaxial" system placing a ribbon (Raven R3 or the like?) with a modest waveguide in front of a 15" wideband woofer.

Something like this is nice:

Click the image to open in full size.

I myself use a (factory) modified Supravox Fieldcoil 8" Fullrange driver on an (acrylic) open baffle with a monpole (sealed box) 2 X 12" active subwoofer below around 50Hz. A compromise for sure, but the results speak for themselves.

Click the image to open in full size.

Quote:
Originally posted by loudandclear
Does the Basszilla have it backwards?
The Basszilla is "borderline". It does keep the Fullrange driver operating at low frequencies, which means there is more controlled directivity at low frequencies, but the crossover point is a little on the high side. Certainly it fits more of my criteria than most speakers. It is (perhaps) interesting that the 'zilla's designer Dick Olsher reviewed and rather liked the Gradient Dipole Speaker (there is a current review over at 6moons.com).

Quote:
Originally posted by loudandclear
What full range driver would work best?
That depends on many factors.

My "ideal" driver would probably be a resurrected Eckmiller Koaxial which was designed in germany in the late 1930's. It had truely co-incident sound sources (the voice coils where concentric) and used a series X-Over. I wrote quite a bit about this one at AA:

http://db.audioasylum.com/cgi/m.mpl?...er&r=&session=

Failing that, Supravox and Phy-Hp make drivers eminently suited for open baffles and they all sound rather good too. The Phy-Hp KM30 is probably closes to my "ideal driver", the Supravox are close seconds unless you use the fieldcoil versions, which are so bloody expensive, I cannot really recommend them with a good concience, but the sound....

The right Lowthers or AER's in a suitable fronthorn are equally quite exceptional and if you have the space for these and maybe even for some architectural LF horns like Mr Roggéro you could have a system that is completely outstanding just as well....

Click the image to open in full size.

So, much depends on the solution you like....

Sayonara
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Old 23rd December 2004, 12:19 PM   #18
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<http://scrounge.org/speak/ultimate.html>



Here is one view, not that I am advocating such lunacy!
(Until I get around to building my own house, that is...)

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Old 23rd December 2004, 12:28 PM   #19
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By the way, has anyone every tried to use the Fostex FW800N
31.5 inch Super Woofer?

I know it's insanely expensive. Just curious.

<http://www.madisound.com/pdf/fostexdrivers/fw800n.pdf>

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Old 23rd December 2004, 12:45 PM   #20
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How about this (on the cheaper side):

http://www.diyhifisupply.com/diyhs_prometheus.htm

http://www.bastanis.com/bastanis/prometheus_en.htm

http://www.baulsaudio.com/cart/produ...db0def5082b106
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