Morel MW144 deceitful specs

[mr_push_pull]

Hi everyone

I acquired a pair of Morel MW144 drivers 2 days ago, with the intention of building a small ported bookshelf. What attracted me about this driver was a very low Fs for its size (45Hz) and extended frequency response (flat up to around 7KHz) with nice off-axis response also. Well, the only strange thing was that the impedance plot from the spec displayed a peak at 70-80Hz, nowhere near 45 Hz, as the table stated. Well, I said, the graph must be wrong! What a perfect example of wishful thinking.

Just a few minutes ago I said to myself... why not run a Google search with "morel AND MW144" to see what other people have built with these? I did this I while ago but got bored quickly (too many distributors pages, too may in russian or chinese).

Well, imagine my surprise when I found these 2 pages:
http://www.snippets.org/pipermail/di...ry/022494.html

And I quote "For what it's worth: last October I bought a pair of MW144's, and I was disappointed to find that my units do not meet the published specs. Fs is way high, Bl is way low..............."

Huh, Fs way too high the guy says? Well, he must be wrong, after all he doesn't quote figures! Well, at a price of over $100 for a 12 cm "midbass" one does not give up hope easily.

But... http://www.audiocad.de/u/bauvor/hathor2/hathor2.html

Omigod! Just give the impedance plot a look... Typical for a closed box, with a driver resonance peak at... 75Hz Wow, and initially I was afraid that a F3 of 55 Hz won't do. And it's obvious that those are the guy's measurements.

Has anybody here measured this driver? Maybe it's not too late for a refund.

[Madmike2]

I cant speak for your speakers. I got my 166's a while back and measured them with my brand spanking new meterman. I cant measure FS but i can everything else and it is really close to what they claim for me . Sorry if you got burned.

[Roy Lewis]

Hello PP

Have a look at, www.iplacoustics.co.uk, he has several models using the 144, including a " TLine ". I built an early version of the latter several years ago and they are still going strong and sounding good, amazing bass for their size. Ivan Leslie the man behind IPL is very knowledgable and helpful, I am sure he can help. His range of TLines kits are excellant, I have built two, M3tl and S3tl, in the past and are superb

Roy

[DanWiggins]

Originally posted by mr_push_pull
Hi everyone
But... http://www.audiocad.de/u/bauvor/hathor2/hathor2.html

Omigod! Just give the impedance plot a look... Typical for a closed box, with a driver resonance peak at... 75Hz Wow, and initially I was afraid that a F3 of 55 Hz won't do. And it's obvious that those are the guy's measurements.

Has anybody here measured this driver? Maybe it's not too late for a refund.

Keep in mind that the response shown in that page is in-box; placing an MW144 in ~4 liters sealed will yield an in-box resonance of 75 Hz. That appears to be the case at the Hathor site. The in-box resonant peak is not representative of the actual Fs of the driver; the resonant frequency of the system is adjusted upwards based upon the ratio of Vb to Vas. And the peak impedance of the sealed box system will occur at the resonant frequency of the box.

Dan Wiggins
Adire Audio®

[mr_push_pull]

Hi Roy

I've been knowing about IPL for some time and also read the TNT review for Ivan's TL that uses MW144.

Don't know, maybe Ivan has his drivers going though some serious quality control? We all know that this one of the difference between drivers for the DIY market and those for OEM customers.
Anyway, if I'll find my suspicions confirmed I'll build a TL with it. Maybe Ivan sells plans for his enclosures?

[mr_push_pull]

Originally posted by DanWiggins


Keep in mind that the response shown in that page is in-box; placing an MW144 in ~4 liters sealed will yield an in-box resonance of 75 Hz. That appears to be the case at the Hathor site. The in-box resonant peak is not representative of the actual Fs of the driver; the resonant frequency of the system is adjusted upwards based upon the ratio of Vb to Vas. And the peak impedance of the sealed box system will occur at the resonant frequency of the box.

Dan Wiggins
Adire Audio®

Hello Dan

Thanks for pointing that out. I guess I haven't done my homework Anyway, something is probably wrong with the Morel specs, but let's some that's in a positive way.
I'll get the chance to measure the real impedance in about a week.

[Zaph]

Originally posted by DanWiggins


Keep in mind that the response shown in that page is in-box; placing an MW144 in ~4 liters sealed will yield an in-box resonance of 75 Hz. That appears to be the case at the Hathor site. The in-box resonant peak is not representative of the actual Fs of the driver; the resonant frequency of the system is adjusted upwards based upon the ratio of Vb to Vas. And the peak impedance of the sealed box system will occur at the resonant frequency of the box.

Dan Wiggins
Adire Audio®

I tested a few of these. Actually, the Fs was that high without a box. The following measurements were taken on an infinite baffle.

Performance was overall pretty disappointing. Bass extension is poor for a driver of that size, efficiency is low, Qts is too high and the response is ragged. Yuck.

[Zaph]

I suppose I better add, that was without breakin. I would expect Fs to go down 3-5 hz after breakin but it's still kinda high.

[David Gatti]

I think it's a bit harsh to use the term "deceitful specs".
We're talking about electomechanical devices which by their nature are difficult to produce with low tolerances. I don't think Morel is attempting to deceive, though they may be accused of showing better than average specs.
Applying the same term to Bose may be a different story, or those companies stating they produce the "worlds best speakers".

[Madmike2]

Also Morel is a hand made speaker if its the israeli ones. Mine is obviously hand made. there was even a finger print on it although that probably was a guy named Serge from SOlen in Quebec