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My Takeaways From ASR Speaker Testing
- Thread starter Ron Texas
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tuga
Major Contributor
When the Spendor BC1 came out Peter Walker (Quad) said that forward-radiation boxes were finally up to par:
https://books.google.co.uk/books?id=SOqCbh2ESOgC&pg=PT34&lpg=PT34&dq=martin+colloms+High+Performance+Loudspeakers+spendor+bc1+peter+walker&source=bl&ots=7mA8r-RzDp&sig=ACfU3U0jVhlmvUQj9ukWWf_zrmgbabC08g&hl=en&sa=X&ved=2ahUKEwjwyNrVyu3oAhWiVBUIHVEfC68Q6AEwAHoECAsQKQ#v=onepage&q=martin colloms High Performance Loudspeakers spendor bc1 peter walker&f=false
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or integrate the measurements with an open source acoustic solver like https://i-simpa.ifsttar.fr/
I am toying with this idea.
One difficult problem with panel speakers is that it is next to impossible to control a large area membrane to vibrate totally in sync at high frequencies. If you do not have perfectly uniform electrical conductivity in your large electrostatic membrane and thus do not have a uniform electric field, or not have an uniform magnetic field for planar magnetics, different areas will move differently. Ditto for mechanical imperfections (non-uniform membrane thickness, non-uniform material properties, non-uniform gap distances, non-uniform tension, etc.)
I wonder how much of people "hearing a box" has to do with them seeing a box. That would be a fun test to do sometime.
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I mentioned earlier that I (single) blind tested a box speaker (Spendor) against the Quad ESL 63 stats, and they sounded similar except the boxy signature of the Spendors allowed me to identify which speaker I was listening to.
So there's a population of one listener, identifying one speaker from one other speaker. I think we need more data.
Were those to speakers identical in every other measurable way--except for the "box signature" such that nothing else could have tipped you off?
Were those to speakers identical in every other measurable way--except for the "box signature" such that nothing else could have tipped you off?
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Agreed, my one little anecdote is useless for establishing anything general.
But since you talked about doing it as a "fun test"...well...that's exactly what it was and why we did it at the time. And since I did it...figured I'd mention it.
Fair enough. 
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I'd forgotten that one. The conjecture was the scattered energy from the Quad helped with spatial quality in stereo. It also would indicate panels listened to in mono isn't a good methodology if you are listening in stereo. While it apparently is for box speakers.That could be a possibility, people not being used to listening to panel speakers. People who enjoy and are used to listening to small standmounts tend to find large speakers slow and not as "spacious-sounding".
The Quad didn't do very well in mono but did a lot better in stereo.
I don't think so and my experience tells that it is not that simple. Panels like Quad, Soundlab and M&L are dipole only in some freq ranges and have lots of interferences and resonances - just differently imperfect than box speakers. The biggest difference is high directivity in midrange 200-1000Hz and high backwards radiation also above 1000Hz (where box speakers don't radiate hardly at all). This means that they behave very differently in a typical "small room" listening setup, be it mono or stereo. Room modes and reflections from boundaries have different peaks and "relations"
I have heard wonderfully good sound and imaging from multiway horns, synergy horns, multiway dipoles and multiway boxed speakers! But they do sound different and most people have personal preference!
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Just a random tidbit. Panels are known to have a small sweet spot. The smallest sweet spot I've encountered by far was with Acoustat Two's. Those had a pair of panels, but they were angle by something like 5 degrees to each other. Those were true head in a vise speakers. A friend had Acoustat 3's which were also angled, but the center panel was firing straight ahead. Much less head in a vise. Others had 1+1's and also less head in a vice, though they had great imaging and no real bass. 2+2's were the most balanced of the Acoustats I've heard, but also head in a vice.
My curved Soundlabs aren't so bad in this respect. Neither were Quad ESL-63's. Original Quads weren't too bad either. Of course way back when original Quads would have been so different than anyone's box speakers. And even in the early 1980's the ESL-63 was also a revelation versus box speakers. When I first heard ESL-63's, I simply said, "I've got to have some of these". I was using Acoustat Two's at the time. Within 3 months I managed to get a pair.
Old Listener
Senior Member
Very short post that makes the right points.
I was thinking about doing this too. How did it go?
Just to add another Data point - I have done blind testing and was always bothered by the "Box Signature"...
Although I no longer have ESL's - I now have gallo speakers, which place each driver in its own "ball" - no boxes, and similarly, does not have the "Box Signature"
I will add that not all box speakers have that signature - but it is present among many very very highly regarded and scored "box speakers" - clearly those used to it, do not notice it...
Don't get me wrong, I'm not saying people aren't hearing anything, I'd just like to try and nail down exactly what it is and what causes it a bit better. My own experience--I have two sets of speakers I've compared A/B (not blind though) an infinite (nearly) number of times for the last two years. One big, one little.
After EQ to match the timbre as exactly as possible and using subs, the biggest difference I am left with between the two is what I can best describe as material from the smaller speaker "sounding like it's coming from a box" in comparison with the bigger speaker. Listening to the small ones in isolation I doubt I'd notice, but switching between the two in real time does reveal it. It's hard to hear with music, but with voices (especially male voices) it's easier to hear. The big speakers just sound more like the material is real, the smaller speakers sound more like a speaker playing the material.
They're both box speakers. And during this time the big ones actually had a much larger, measurable issue with a box resonance leaking through the port. It was at around 200 Hz though, so maybe it got lost in the SBIR issues that occur around there and maybe we aren't quite so sensitive at such low frequencies....
The most likely reason I can speculate might be the cause is that the small speakers are two-ways, the large speakers are three-ways. The large speakers' midrange has its own separate sealed box. For the two way speakers, you're expecting the entire volume of the cabinet and a large woofer to be resonance-free up to ~2K Hz. For the large speakers, the big box is done at 350 and from there on you've got a small midrange driver in its own small sealed cabinet providing the sound completely free of the "big box."
So my question for those who have heard what they think is a "box sound"--particularly those who have noted that some box speakers have it and some do not--is have you paid attention to the design layout of the speakers you think have it verses those that don't and noticed any patterns?
After EQ to match the timbre as exactly as possible and using subs, the biggest difference I am left with between the two is what I can best describe as material from the smaller speaker "sounding like it's coming from a box" in comparison with the bigger speaker. Listening to the small ones in isolation I doubt I'd notice, but switching between the two in real time does reveal it. It's hard to hear with music, but with voices (especially male voices) it's easier to hear. The big speakers just sound more like the material is real, the smaller speakers sound more like a speaker playing the material.
They're both box speakers. And during this time the big ones actually had a much larger, measurable issue with a box resonance leaking through the port. It was at around 200 Hz though, so maybe it got lost in the SBIR issues that occur around there and maybe we aren't quite so sensitive at such low frequencies....
The most likely reason I can speculate might be the cause is that the small speakers are two-ways, the large speakers are three-ways. The large speakers' midrange has its own separate sealed box. For the two way speakers, you're expecting the entire volume of the cabinet and a large woofer to be resonance-free up to ~2K Hz. For the large speakers, the big box is done at 350 and from there on you've got a small midrange driver in its own small sealed cabinet providing the sound completely free of the "big box."
So my question for those who have heard what they think is a "box sound"--particularly those who have noted that some box speakers have it and some do not--is have you paid attention to the design layout of the speakers you think have it verses those that don't and noticed any patterns?
I recall that the 80's Boston Acoustics speakers, which were a wide flat shape, rather than the standard coffin, didn't have it noticeably - they had very wide front baffle... very shallow in depth - the A400, A150, A100 - a really nice sounding series.
The A400 would give the Quad ESL63 a run for its money at less than a third the price, and with solid mid bass to boot.... - no boxiness
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