So what I heard was simply FR irregularities? The materials had nothing to do with it?
OK, believe that if you will. I do not. I heard them. I have never noticed those FR quirks alone imparting a particular material signature to a speaker.
Having heard them with my own ears, I claim that your conclusion is wrong. It would be interesting to have a pair that could be EQed flat and tested. I'll place good money on the fact that EQ alone could not remove the paper and wood sound. Conversely, EQ will not add that type of coloration to a speaker made of other materials.
I do understand that it is easy to be tricked or make mistakes in what we hear. In this case, I seriously doubt it was anything other than the sound of the materials themselves.
OK, believe that if you will. I do not. I heard them. I have never noticed those FR quirks alone imparting a particular material signature to a speaker.
Having heard them with my own ears, I claim that your conclusion is wrong. It would be interesting to have a pair that could be EQed flat and tested. I'll place good money on the fact that EQ alone could not remove the paper and wood sound. Conversely, EQ will not add that type of coloration to a speaker made of other materials.
I do understand that it is easy to be tricked or make mistakes in what we hear. In this case, I seriously doubt it was anything other than the sound of the materials themselves.
I "wood" certainly agree!
I've heard a few speakers built of very dense, marine plywood (Nantex) that had no particular sound to them. No box talk. That's about as remarkable to hear has boxes with strong coloration. You don't expect it.I can't really say where the Harbeth sits on the scale of box coloration, having not directly compared it to others. It may be better or worse. My point is that it certainly DOES have coloration, coloration that to my ear sounds just like wood. Coincidence, perhaps. But I doubt it.
Hi,
The point of the damped thin wall cabinets is what is doesn't do
compared to more rigid less damped cabinets. Not what is does,
you'll never get ultra clean hard hitting bass out of them, but
for a lot of music genres it simply does not matter that much.
I suspect the naysayers have never compared the two options.
They are both valid options, and sound distinctly different.
rgds, sreten.
The point of the damped thin wall cabinets is what is doesn't do
compared to more rigid less damped cabinets. Not what is does,
you'll never get ultra clean hard hitting bass out of them, but
for a lot of music genres it simply does not matter that much.
I suspect the naysayers have never compared the two options.
They are both valid options, and sound distinctly different.
rgds, sreten.
ORNJ,
it is never that simple.
A lossy cabinet made of 12 mm ply is never that rigid than a cabinet made of 16 mm MDF with braces. So what's the difference in the real world?
The lossy panels will bend when the woofer moves in and out, with the same frequency. They're not resonating, just bending in and out. The stiff panels will bend, too, but much less. Because these panels have a stiffness like a spring, they modify the stiffness of the internal volume. The panel's spring and the volume air's spring work in series, so the resulting compliance is the sum of both compliances (note that I switch from stiffness to compliance here). The volume effectively gets larger, changing the alignment. That's effect #1.
When the cone moves in, the panels move out. Thereby they produce sound, adding to the sound from the woofer. Because the movement is 180° out of phase, it is a reduction in total bass output. That's effect #2.
And then there's the panel resonance, usually above the deepest bass. The panels store energy in those resonances, maybe affecting the sound. That's effect #3.
How big is the impact of these effects? Can't tell, depends on internal volume, area of each panel, cone area, frequency, audibility threshold. The available data shows a quite high threshold for effect #3, so I wouldn't put much effort in eliminating...but you have to consider it.
Does any of these effects reduce "cleanness" of the bass? Maybe. #1 and #2 are definitely capable of doing so. A changed alignment + reduced bass output may give you such a perception. Of course, you have to compare speakers of same size, same driver lineup, same crossover, same bass principle (CB, BR, or else). Otherwise, the whole test is worth nothing. Never heard of anyone doing this*.
*To all of you who now say: I did!
Did you really? Was there nothing that could have falsified that test? No target for critics?
it is never that simple.
A lossy cabinet made of 12 mm ply is never that rigid than a cabinet made of 16 mm MDF with braces. So what's the difference in the real world?
The lossy panels will bend when the woofer moves in and out, with the same frequency. They're not resonating, just bending in and out. The stiff panels will bend, too, but much less. Because these panels have a stiffness like a spring, they modify the stiffness of the internal volume. The panel's spring and the volume air's spring work in series, so the resulting compliance is the sum of both compliances (note that I switch from stiffness to compliance here). The volume effectively gets larger, changing the alignment. That's effect #1.
When the cone moves in, the panels move out. Thereby they produce sound, adding to the sound from the woofer. Because the movement is 180° out of phase, it is a reduction in total bass output. That's effect #2.
And then there's the panel resonance, usually above the deepest bass. The panels store energy in those resonances, maybe affecting the sound. That's effect #3.
How big is the impact of these effects? Can't tell, depends on internal volume, area of each panel, cone area, frequency, audibility threshold. The available data shows a quite high threshold for effect #3, so I wouldn't put much effort in eliminating...but you have to consider it.
Does any of these effects reduce "cleanness" of the bass? Maybe. #1 and #2 are definitely capable of doing so. A changed alignment + reduced bass output may give you such a perception. Of course, you have to compare speakers of same size, same driver lineup, same crossover, same bass principle (CB, BR, or else). Otherwise, the whole test is worth nothing. Never heard of anyone doing this*.
*To all of you who now say: I did!
Did you really? Was there nothing that could have falsified that test? No target for critics?
Anything we can measure still only scratches the surface. A trained ear is much more sensitive.
In the end, the target instrument for the device is the ear/brain not a mic.
dave
If you want to believe Harwood over your own ears then that is your business...
When Pano gave his description i knew exactly what he meant... i lived with Spendor BC1s for sometime, one of the 1st commercial speakers following the BBC way, and it suffered the same colourations. A thoroughly enjoyable speaker, but not neutral.
Keep in mind that this all happened over 40 years ago... most speaker cabinets are still crappy, but the BBC approach can be bettered IME.
dave
Hi,
Unfortunately its not that simple. Smaller boxes (like the LS3/5A)
don't have very thin walls and lots of mass loading to take the
resonances below a typical cut-off, say 200Hz.
The technique was developed pre subs and pre AV and works
best AFAIK with 30L to 60L cabinets, i.e. a classic 8" 2 way,
and these for most music of the period don't need a sub.
The signature of a 2cuft cabinet with thin walls and lots of
damping is far less than thicker stock with some bracing.
The fact that the walls move is easy to ascertain, you can feel it.
Can you hear it ? I couldn't for most material, that is the point.
rgds, sreten.
A trained ear can detect errors. But it can't find the source of the error. You'll need measurements for this.
Harwood used measurement and empirical data.
Again, this is called science.
Physics have changed in the last 40 years?
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Good science recognizes its limitations. Current audio measurements are primitive. You keep using FR as an explain all. That is like looking at the surface of the ocean and guessing what the bottom looks like. If the only tool you have is a hammer everything starts looking like a nail.
Understanding of physics has changed dramatically.
For one Chaos/Complexity theory for one. Tools to explore the 95% of problems that previously had been ignored because we had no mathematical tools to deal with them,
And materials technology has advanced considerably.
A practical example of the growth in both is that your smart phone would run circles around the biggest computer in the days of the BBC study.
dave
I don't understand. If the panels move, then the back is moving in the same direction as the cone, the sides 90° to the angle of the cone and the front in the opposite direction. How does that make 180°?
Good science is making observations and trying to explain it. The explanation can be done by measurements.
What is your explanation?
If the cone moves in, it generates a positive pressure in the box. This pushes the panels out. Cone moves in vs panels move out, that's 180° in sound output. Remember that at those low frequencies the cone and the panels have nearly no directivity.
Ya right
If it is not that easy, what is it then? Tell us, we all want to know.
Well, that's a simple way of looking at it, sure. But since the panel sizes, shapes, radiating area and angles are not the same as the cone, it's more complex than that.
The main problem, of course, is that whether the movements are at 180° or not, they won't be a perfect mimic of the cone movement. So even if they could cancel each other out, they don't.