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Speaker sensitivity

Sal1950

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RayDunzl

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You trying to make toast?

I'm just providing a non-arm-waving and repeatable data point with amusing calculation for further discussion or conjecture.
 

amirm

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Blumlein 88

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You need to measure the voltage on the grids of your MLs. That is fun.
 

RayDunzl

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You need to measure the voltage on the grids of your MLs. That is fun.

I've heard the diaphragm is charged to 2500V, and the stators are driven by a step-up transformer, maybe 100:1 bump on the voltage the amps emit.

They put a nice musical EMF waveform into the air, swamps all the non-musical noise..

I wasn't able to get the backs off to poke around inside, when I tried, in 1999 or so. I'll just have to be content with a photo and my imgination of what's going on in there. Since they work without known fault, I follow my rule - If it ain't broke don't fix it - which serves me well.

My audio buddy is replacing the panels on his CLS, so I'll get to see what is inside those whenever they arrive.

As an aside, for this reason you actually want high voltage rated speaker wires!

They're 600V rated, if laid parallel, does that give 1200V between them? 138V would be the unlikely to be seen max on my little amps, 240V on the big boys of the series.
 

amirm

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They're 600V rated, if laid parallel, does that give 1200V between them? 138V would be the unlikely to be seen max on my little amps, 240V on the big boys of the series.
As long as they are not low voltage wire rated to 30 volts and such, you are good.
 

DonH56

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Wires are typically rated Vrms so 600 Vrms; unlikely you'll exceed that with any reasonable amplifier... That would be about 45 kW into 8 ohms, 90 kW into 4 ohms.
 

Vladimir

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Brace yourself gentlemen.

 

edd9000

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I like sensitive speakers, I put the extra dynamics down to power compression. Electrostatics shouldn't power compress either.

In my case though it was mostly because I liked to build low powered amplifiers, and I like what CD horns can do.
 

Fitzcaraldo215

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I like sensitive speakers, I put the extra dynamics down to power compression. Electrostatics shouldn't power compress either.

In my case though it was mostly because I liked to build low powered amplifiers, and I like what CD horns can do.
Well, electrostats can power compress drastically, due to the hard excursion limits imposed by the fixed stators on the membrane vibrating in between. In old, 'stats like original Quads, that meant arcing. Newer stats usually have protection against that, sometimes in an electronic limiting circuit.

My Martin Logans insulate the stators to prevent arcing at the expense of imposing a higher capacitance load. But, my ML's are hybrids with dynamic woofers. So, long excursions in the bass are not an issue for the 'stat panels. And, in truth, I never feel dynamics are limited, though they still are mechanically limited in theoretical maximum excursion by the stators, which is much less a problem above the bass. Dynamic limitation is not something I ever hear.

Full range 'stats are also limited by natural low end attenuation as a result of dipole cancellation in the bass.

The very best way to improve system dynamics IMHO is to add a good powered subwoofer with a high pass xover, freeing the main speakers from high bass excursions. In other words, horns may have their plusses and minuses - efficiency with correspondingly low amp power requirements being a key advantage - but I think plenty more than sufficient dynamics are obtainable via other means.
 

edd9000

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Ill be honest its not something I have thought about that much. I did mean they don't compress within their range, and small panels can be spl limited by the excursion limit.

All things being equal a larger driver needs less excursion, thus typically lower distortion to higher spl, these day drivers are getting much better with ever increasing linear xmax, but like I said all things being equal.

More power means more heat, which will cause power compression, big PA drivers rated for 800w tend to dissipate heat better, they are more sensitive you are using much less power, win win.

I'm not sure all dynamics simply occur in the bass, but yes, I'm a proponent of subwoofers, wouldn't be without out one.

When I say horns, I like CD waveguides, I like the even dispersion over a controlled area, Geddes stuff. Most "normal" horns don't do much for me.

It boils down to the recording a lot too. If it has 6db of dynamic range, its never going to be dynamic. I have some Flim and the BBs cds with 20db+, they sound pretty punchy on most things, on dynamic systems, it makes you blink.

Id never noticed the SPL logging in REW before, Ill have to drag various speaks out to compare.
 

RayDunzl

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A while back, I did a compression test up to reasonable (too loud for single frequency) levels on my panels, and saw nothing to hint of compression.

Lower left contaminated by ambient noise.

Levels were bumped 2dB on each pass, result is pretty much +/- .1dB, measured at the listening position. Crossover to cone woofer at 180Hz

upload_2017-4-9_12-21-0.png
 

Fitzcaraldo215

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A while back, I did a compression test up to reasonable (too loud for single frequency) levels on my panels, and saw nothing to hint of compression.

Lower left contaminated by ambient noise.

Levels were bumped 2dB on each pass, result is pretty much +/- .1dB, measured at the listening position. Crossover to cone woofer at 180Hz

View attachment 5981

Interesting, Ray. It seems to indicate that Martin Logan did their engineering right to avoid compression in most reasonable circumstances. The crossover to cone woofer made that task much easier. I am sure they could be driven into compression/distortion at some level, but not one that would be comfortable or necessary in most rooms.
 

Fitzcaraldo215

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Ill be honest its not something I have thought about that much. I did mean they don't compress within their range, and small panels can be spl limited by the excursion limit.

All things being equal a larger driver needs less excursion, thus typically lower distortion to higher spl, these day drivers are getting much better with ever increasing linear xmax, but like I said all things being equal.

More power means more heat, which will cause power compression, big PA drivers rated for 800w tend to dissipate heat better, they are more sensitive you are using much less power, win win.

I'm not sure all dynamics simply occur in the bass, but yes, I'm a proponent of subwoofers, wouldn't be without out one.

When I say horns, I like CD waveguides, I like the even dispersion over a controlled area, Geddes stuff. Most "normal" horns don't do much for me.

It boils down to the recording a lot too. If it has 6db of dynamic range, its never going to be dynamic. I have some Flim and the BBs cds with 20db+, they sound pretty punchy on most things, on dynamic systems, it makes you blink.

Id never noticed the SPL logging in REW before, Ill have to drag various speaks out to compare.

Agreed, not all contributors to dynamics are in the bass frequencies. However, that is where the biggest speaker excursions and biggest amp power demands normally occur with music, so that is where speaker dynamic limitations, if any, usually show themselves.
 
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