Merlin VSM-mm's a good value at $3000 used?

Shadorne- can you translate the speaker designer talk into english for us peons. I think that you really have something there and I would like to understand it.

Our ears are very sensitive to harmonic distortion in the bass.

This is news to me. In the old times, our ears' sensitivity hit the ceiling over 300Hz to ~6kHz (ballpark figures).

HD in the bass can reach very high levels; 3% at equal loudness (as per F-M or "phon" curve) is extremely good. But, usually, HD in the bass is perceived as bloated midbass...

Fletcher-Munson egual loudness curves imply that 3rd order harmonic distortion from a 20 Hz fundamental needs to be below 1%, or over 38 dB down, in order that it is less loud than the 20 Hz fundamental!!!

Here you've lost me, too. You are referring to the "phon" curve?

Gregm and Swampwalker,

Sorry I was unclear.

Hearing sensitivity rises very rapdily from 20 Hz to 100 Hz. The slope is roughly 24 DB/Octave. This means a fundamental note at 20Hz and its third order (80 Hz) harmonic will sound equally loud when the third harmonic (80Hz) is played at 38 db lower level than the fundamental.

In practice this means that we are ultra sensitive to harmonic distortion from extreme LF notes...often the perception of bloated/boomy/one note bass is due to harmonic distortion. Speakers with apparently awesome bass output for their size usually exploit this distortion to good effect.....but it isn't music its just distortion!

gregm and shadorne,
some interesting facts about the 8545-06 and the superbam.

Driver/Superbam response V.S. Distortion

1) A small driver with a long X-Max ( linear response offers clean, high spl). This is equal to a larger driver with a shorter x-max.

2) The Superbam speaker management system offers a high pass filter on the bottom end (28 Hz) plus a very narrow boost at 35 Hz which raises the spl of the bass and keeps the driver in linear response longer at higher output.

3) By keeping the driver in linear response ( X-MAX) and out of non-linear response (X-MECH), 2nd and 3rd
order harmonic distortion is minimized at higher spl.

4)The design of the driver itself ie: re-enforced cone, cone damping material and a copper shorting ring, minimizes doppler effects and harmonic distortion.

5) 2nd and 3rd harmonic distortion will cause bass to sound overy full, ill-defined and in extreme cases, wooley, mushy or fuzzy. In the mid-bass/ mid-range mild distortion can sound “warm and full” but at higher distortion, it can sound like a guitar fuzz-tone sound. In tweeters it can sound grating or eeky.

6)Boomy-ness is more a factor of over pressurizing or “loading” up the room. Bass likes to couple to large flat surfaces ie: wall and floors and in doing so (depending upon the length of the surface verses the frequency) can result in as much as a 12dB gain for that frequency (standing wave) thus the one note bass effect.

7) With BAM keeping the low end excursion of the driver in check, the speaker can play louder in linear and non-linear modes before actual damage to the driver.

8) With the Bam keeping the driver in linear response (voice coil in the magnetic gap) the voice coil is being cooled much more effectively (as opposed to out of the gap/non-linear response) therefore minimizing power compression and the resulting distortion.

bobby at merlin

2nd and 3rd harmonic distortion will cause bass to sound overy full, ill-defined and in extreme cases, wooley, mushy or fuzzy. In the mid-bass/ mid-range mild distortion can sound “warm and full” but at higher distortion, it can sound like a guitar fuzz-tone sound. In tweeters it can sound grating or eeky.

Boomy-ness is more a factor of over pressurizing or “loading” up the room. Bass likes to couple to large flat surfaces ie: wall and floors and in doing so (depending upon the length of the surface verses the frequency) can result in as much as a 12dB gain for that frequency (standing wave) thus the one note bass effect.

Thx, bobby you explain it much better than me. "Overly Full, ill-defined, warm and full, wooley, mushy or fuzzy" is more what I meant with regard to harmonic distortion....I like Gregm's "bloated" too.... how about "Muddy" LOL.

The difficulty comes when some may say that a correct sounding bass with very little harmonic distortion is "overly tight, dry, anemic, lacking warmth, fatiguing, tiring or thin" sounding.

Therefore some consumers will prefer a distorted speaker over an accurate one. Go Figure! It ain't even close to accurate music reproduction...but it sounds pleasant and they prefer it and they don't lack for bass!!!

Typical speakers can have upwards of 10% harmonic distortion at ultra LF (when played at high but not excessive SPL's)...not yours of course.