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Tiny ground-effect omnidirectional biamped system
Tiny ground-effect omnidirectional biamped system
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Old 5th November 2012, 02:56 PM   #11
trevmar is offline trevmar  United States
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Originally Posted by soundaatma View Post
Hi Trevor,
very interesting design.
The Peerless FR on the response graph is omni only upto 4Khz. So does the the smaller tube also need to be kept at ground level
The smaller tube is better at ground level. It relies on the ground effect for its lows, and you will find that the HF response is pretty flat at 45 degrees off-axis). In practice, the (omnidirectional) sound field fills the room and the location of the speakers becomes less obvious.

Quote:
Originally Posted by soundaatma View Post
BTW, any reason you preferred to use the Peerless FR instead of the Aurasound NSW2 used in the Pluto
Did you also experiment with the idea that perhaps bipole FRs could also possibly give near omnipolar radiation
Yes, the Peerless is a nice, clean speaker with an excellent transient response. I never really warmed to the 'icy' sound of the Aurasound. Try the Peerless - you will be surprised But don't just listen to them on-axis, let them give you an omnidirectional sound field

ps: I tried a lot of drivers. I used these Peerless because they sounded cleanest. Even the 8 ohm version of the Peerless drivers was not as crisp...

Last edited by trevmar; 5th November 2012 at 03:05 PM.
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Old 5th November 2012, 03:37 PM   #12
mondogenerator is offline mondogenerator  England
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Ive been messing around with something similar, (albeit using seperate satellites, and presently minus the Sub) using Tangband W2-800SL in ~50cc tea-light holders (40x40x50mm truncated cuboid).

They sound fairly good, to my ears. Actually the graphs looked better than the Peerless, which is why I got the TBs, but the results dont always concur with specs so Im not critising in the slightest. Interestingly, the cube's F3 is around 450Hz (low Qts ~0.24) so 2 subs are in the pipeline, to avoid localisation as much as possible.

Out of interest what F3 do the Peerless have in the small tube enclosure?
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Old 5th November 2012, 03:46 PM   #13
trevmar is offline trevmar  United States
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Originally Posted by mondogenerator View Post
Out of interest what F3 do the Peerless have in the small tube enclosure?
Details attached (P980983 in 8 inches of 2 inch pipe)
First is response, then Power handling vs frequency.

Let's see .. your 90dB limits us to 200Hz and above Guess where I put my crossover Great ears must think alike
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File Type: jpg 8inches_2inchpipe_P980983_power.jpg (64.3 KB, 266 views)

Last edited by trevmar; 5th November 2012 at 03:49 PM.
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Old 5th November 2012, 04:25 PM   #14
mondogenerator is offline mondogenerator  England
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Haha!

The Qts and lower Fs of the Peerless makes a big difference here, with a Qt=0.24, Vas=0.23, and Fs=160, the TB fits into a Sixth of the volume (sealed)

Had I gone vented instead, my F3 would be better (~265Hz).

With such a small 'baffle' BSC is a big issue. So I came up with a multipurpose baffle. An A4 paper sized piece of PU foam, 1 inch thick. Hole cut into the middle and cube shoved in there. Ta da! Multipurpose diffraction reducing, baffle step reducing baffle which doubles as transit protection!

More than 90dB? Hahaha, neither the peerless or TB would take much more than 90dB anyway....Did a Badger hide the x-over? I certainly didnt have room for mine inside the cube!

Just as well
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Last edited by mondogenerator; 5th November 2012 at 04:35 PM.
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Old 5th November 2012, 04:46 PM   #15
trevmar is offline trevmar  United States
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Originally Posted by mondogenerator View Post
Did a Badger hide the x-over? I certainly didnt have room for mine inside the cube!
I use a MiniDSP as an active crossover/compensator. And Bi-Amping... That is one of the reasons the design works so well Did you look at how many poles and zeroes were in my compensation DSP coefficients?

I am quite happy putting up with the huge size of 8 inches of 2" pipe for my HF enclosure. After all, what good is an enclosure if it does not take up floorspace?

Mind you, the Seas woofers are huge! 16 inches of 6 inch pipe! It is tough to find space for them. But fortunately they can be a foot or so from the HF drivers, since the xover is at 200Hz...
.

Last edited by trevmar; 5th November 2012 at 04:55 PM.
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Old 5th November 2012, 05:47 PM   #16
Elias is offline Elias  Finland
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Ground Effect Omnidirectional
I like this. Looks like flooder now has a proper scientific name


- Elias
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Old 5th November 2012, 05:57 PM   #17
trevmar is offline trevmar  United States
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I like this. Looks like flooder now has a proper scientific name
True, Elias. But in my case there is emphasis on the omnidirectional, point-source, design. As in -- no multiple arrays of horizontally facing drivers The choice of suitable drivers is, of course, key

And the drivers I chose do come from Scandinavia Where the flooder became popular Probably not coincidence
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Old 5th November 2012, 06:08 PM   #18
mondogenerator is offline mondogenerator  England
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I have to admit I havent seen the DSP bits, on the site I presume:-) Ill have a look, but Im a DSP virgin

The Tangbands could work well in a similar 8inch pipe, vented rather than sealed. I think the Peerless have the edge in low end reach though, thats sure. I remember looking at the Peerless, I dont recall which model, I think it was the inverted surround version, and it had a peak that put me off. Instead I got the Tangband, sacrificed some low end extension for the smooth rise which would be easier to deal with (passively, or at least in analogue domain)
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Last edited by mondogenerator; 5th November 2012 at 06:19 PM.
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Old 5th November 2012, 06:13 PM   #19
trevmar is offline trevmar  United States
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Im a DSP virgin
The MiniDSP is wonderful - you 'draw' the curve(s) you want, and it executes I am never going back to passive xovers...
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