Interesting read I found on Lossy Cabinet designs by Harbeth - Page 9 - diyAudio
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Old 24th November 2012, 05:18 PM   #81
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If you decoupled both cabinets properly: yes.

And the bass cabinet must be that stiff that the fundamental resonance is considerably above the crossover region.
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Old 25th November 2012, 08:52 AM   #82
DrBoar is offline DrBoar  Sweden
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limono all UK reviewers have to have a pinch of salt added. In the case of Practical HiFi a cart load of NaCl. I remember a group review of tube power amps including a Luxman that performed flawlessly measured well and was very well built. Not recommended as it was not musical or somehing. The UK amp TVA-1, measured badly, hummed and the paint flaked of and to top it of one of the amps cought fire during the test. But as it was "musical" it was recomended buy if the manufacturer could sort out these minor flaws...

I think you bring up and important thing with the rooms and ways of building, when I lived in the US I was surprised at the very flimsy way houses are built.
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Old 25th November 2012, 10:25 AM   #83
system7 is offline system7  United Kingdom
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Indeed, Dr. Boar, it is no coincidence that the smarmy, untrustworthy character in US films is usually a British HiFi reviewer.

Click the image to open in full size.

The Living Voice Avatar is an interesting loudspeaker more in the Lynn Olson "Ariel" mold, IMO. But a terrific read about it here which makes many good points about a speaker with a bit of magic:
6moons audio reviews: Edward Barker

Back to Harbeth. The Harbeth Compact 7ES-3 is an interesting take on the 8" bass, 1" tweeter idea that gathers some praise and may suit the British upper classes' drawing rooms:
Click the image to open in full size.
StereoTimes --

I would guess we have said enough about the tiny LS3/5A style Harbeth P3ESR already, but working class people living in tiny British Brick Terrace houses may find them of interest, but probably can't afford them:
Click the image to open in full size.
6moons audio reviews: Harbeth P3ES

Hope that helps. Clearly not for our American cousin's rooms which are evidently the size of aircraft hangars.
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Well, there it is! Best regards from Steve in Portsmouth, UK.
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Old 25th November 2012, 11:10 AM   #84
tinitus is offline tinitus  Europe
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wow, thats a lot of nice DIY clones you have collected there
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Old 25th November 2012, 11:24 AM   #85
system7 is offline system7  United Kingdom
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Quote:
Originally Posted by tinitus View Post
wow, thats a lot of nice DIY clones you have collected there
Sarcasm, no? I really feel no need to discuss cabinet construction any further since it is already covered for diy purposes:
Interesting read I found on Lossy Cabinet designs by Harbeth

If you want to build something as remotely good as a Harbeth, there are many aspects to consider. Personally, I like Alan Shaw and have no interest in dissecting his genius or secrets. I have the same high regard for Joachim Gerhard.

Now YOU tell ME something interesting.
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Old 25th November 2012, 11:47 AM   #86
Baldin is offline Baldin  Denmark
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Here some experimental and measurement data on different materials:
(Use google translate )
HSI :: Luidspreker kast materialen onderzoek

I once had a link to a german site where you could actually play examples of how the different marerials sound .... but cant find it anymore ....

I think a sandwich approach might give the best of more worlds ...
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Old 25th November 2012, 11:59 AM   #87
sreten is offline sreten  United Kingdom
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HI, sreten, how did I guess you didn't lay out big bucks for your Spendors?
Such a tightwad!
Hi,

I bought them building a budget system for someone else and
ended up with them when he moved to Japan. 120 including
good stands for a used pair of Preludes (not bad). System also
had a rechargeable battery powered preamp / mosfet power
amplifier I aquired for him for 60, topped off with a IIX/Rega.

rgds, sreten.

Click the image to open in full size.

HiFi Choice Best Buy and all that at about 280 at the time.
Detuned the port, inspected the x/o, and left it well alone.
Classic BBC type sound, probably still very nice today.
Monsterously sized magnet on the short coil bass/mid.

The side walls were damped chipboard, as thin as they appear above.
Front was plain 18mm chipboard, the rear plain 12mm ply, I recall.

Basically the BC1 bass/mid, built into a more cost effective speaker.
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Last edited by sreten; 25th November 2012 at 12:19 PM.
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Old 25th November 2012, 12:04 PM   #88
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by system7 View Post
This thread is turning into the usual over-complication, I'd say.
Quote:
Originally Posted by system7 View Post
If you want to build something as remotely good as a Harbeth, there are many aspects to consider.
no problem, its simple
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Old 26th November 2012, 06:22 AM   #89
Baldin is offline Baldin  Denmark
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Found the link to the site where some folks have both measured and recorded the sound of different materials and sandwich combos .... take a look and listen
HAUPT

BR Baldin
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Old 26th November 2012, 10:19 AM   #90
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Originally Posted by Baldin View Post
Found the link to the site where some folks have both measured and recorded the sound of different materials and sandwich combos .... take a look and listen
HAUPT

BR Baldin
Great link, thanks.

Note that some have a real audible pitch to them and others are more "tick" than "tonk". The bitumen damped ones are generally good.

These are double cabinets, front and back, so only cabinet radiation is heard.

Much confusion abounds about the Harwood experiments with most audiophiles offended by the thought that ever thicker walls wouldn't be always better.

The way to look at it is that you might be offered your choice of 20 pound cabinets. You could have 20 lbs of solid MDF, no damping. You could have 18 lbs of MDF and 2 lbs of surface damping, or you could have 10 lbs of MDF with 10 lbs of damping. Under those scenarios the 10/10 combo would be best. It would have the lowest level of resonance and the least audible cabinet breakthrough. Harwod even showed that if the choice was a 10 lb cabinet with 10 lbs of damping and a 20 lb cabinet with 10 lbs of damping, that the 10 lb cabinet was probably better, the more massive and rigid cabinet would respond less to the damping.

In the field of architectural acoustics they study this as wall breakthrough from one room to the next. Walls are rated for their TL transmission loss or STC (a single number for loss performance rather than a curve). It is well known that the limp suspended mass is an ideal case for issolation. It has no resonances and rises 6dB per Octave in its TL. This could be a heavy rubber sheet or lead power loaded curtain. Add stifness to the equation and you have a 2nd order system with a resonance somewhere. TL may increase at low frequencies (as well as high frequencies) but some midrange f will exist where the wall is at resonance and transmission will be total.

Damping is the only way to reduce transmission at resonance.

David S
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