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In Reply to: RE: A funny story about square wave test on speakers posted by beppe61 on December 13, 2014 at 23:34:18
Since there are many 'good' speakers that don't reproduce square waves, at the present state of the art the ability to reproduce them is probably not important. But that doesn't mean the ability to reproduce them doesn't matter. If a speaker can do square waves, all other things being equal, it's obviously a more accurate reproducer. A square wave implies wide bandwidth and accurate transients.
But at what frequency is the square wave? The rule of thumb is if an item(amp, speaker) is sine wave flat at 10 times the square wave frequency then the square wave should look good if the phase response is decent. That's probably why a Quad can do a 1 KHz square wave but I doubt it can do a 10 KHz one, not a criticism. And if I recall the B&W DM6, a 3 way dynamic speaker, could do a reasonable 1 KHz square wave . It had step back for time alignment and had 1st order crossovers for about an octave(but went up to at least 3rd order beyond that). It was quite clear sounding for its day.
This, like any audio question is more complex than simple yes/no answers.
Follow Ups:
Hi i found this ... unfortunately not very clear
I do not have experience of the Rehdeko speakers mentioned
But they seem to reproduce a SW quite well from about 100 to 5300 Hz
Another brand that supports the importance of a correct reproduction of a SW signal.
Thanks again.
Kind regards,
bg
I bet the microphone was right at the speaker and the level was very low.
Nonetheless, I agree that one learns lots from square waves.
Now that I have looked at the pictures I am surprised they are not single driver - obviously first order crossover to the tweeter.
They do not look unusual.
Hi and thanks a lot for the very helpful reply
Yes you are right ... it is a not completely "transparent" to give test results
And i think that all the test freqs were in the woofer range
that could be a driver of the wideband type maybe even without crossover
But in general i like the idea of an accurate speaker
Then there is the problem to define what "accurate" means
With a rifle everything is much easier ... but with a speaker ?
The very trivial definition is a speaker that does not distort "too much" the test signal
If this happens only very close to the speaker and for very low level ... let's stay in the near field !
Seriously i am sure that there are some speakers that are quite accurate also at a good distance and at high SPLs
But i do not know which they are.
Thanks again.
Kind regards,
bg
it would be REALLY interesting if they showed a test at a low level and another at a higher level with some indication of what level has been used for each.
The higher level one will be much worse but would still be educational.
To reproduce a SW even at a low level is impressive.
Just as with an amplifier with high efficiency speakers most of what we hear is at a "low" level.
I have long thought of the SW as every test in one. Of course, Peter Moncrief taught me this. Hope I spelled his name correctly.
Hi and i think this is may main question
If a good SW response qualifies a speaker as accurate
After this answer everthing follows
If a speaker presents a good SW only at certain levels or frequencies could mean that it is accurate only in those conditions
There are some drivers that for me are highly "suspectable" of good accuracy at high levels, compression drivers loaded with rightly designed horns
But i have no test reports to confirm this feeling
Of course they are limited in bandwidth, but in their "natural" range i think that they are quite accurate and also at pretty high SPLs.
Accuracy is everything if you really want to hit the target.
Thanks again
Kind regards,
bg
Edits: 12/15/14
John Dunlavy worked on antennas (radar)in WWII. Radar's relation to sound should be obvious. His sine qua non was the step response and he strove for his speakers to be in phase and time aligned. Years of owning his SC IVs and listening to other speakers convinced me that he was right. My Reference 3A Grand Veenas confirm his engineering and listening experience.
and you undoubtedly could hear polarity with these (appropriate recordings assumed).
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
http://www.audiocheck.net/audiofrequencysignalgenerator_squaretone.php
.
Hi and thanks a lot for the very valuable advice
So can we agree that at least the SW response test gives a measure of a driver/speaker accuracy ? That is not useless ?
The consequence is that a driver can be accurate only in the range when it reproduces a good SW
This could be interesting to select a driver and its working range (that should be the range of SWs that it can reproduce nicely).
And the same of course applies to x-overs and any other circuit or tansducers.
Not only.
For instance ... is possible to record a square wave on vinyl ?
with what accuracy ? and the cartdrige ? is able to reproduce it ?
Thanks again.
Kind regards,
bg
Edits: 12/14/14 12/14/14
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