FYI: MJ Acoustics Reference 100 & 150 Subwoofers

MuFu

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Hi,

I thought since there is currently no mention of these subs on the MJA website I'd post the info they sent me here. Please excuse the marketing BS (hehe) and any spelling mistakes etc; I just quickly OCR'd the leaflets this morning.

==========

Reference 100

PICTURE

SPECIFICATIONS:
120watt DC-coupled Bi-Polar Amplifier *
Speaker and line level inputs with Gain Control Range 80dB *
Neutrik Speakon connector (Gold Plated) (High level 100k ohm) *
Unbalanced RCA (phono)(Gold Plated) (Low level 10k ohm) *
Sophisticated crossover circuit - variable increments between 30Hz and 120Hz *
Straight-through LFE Bypass filter switch * Phase Control infinitely adjustable between 0° and 180° *
Frequency response 13hz to 120hz * A.S.P. (Automatic Speaker Protection) *
D.A.M.P. (Digitally Accurate Microprocessor) *
Specially designed cabinet structure, volume, and configuration made from inert 18 & 30mm MDF *
Digital Display with power output meter and frequency setting * Switched fused IEC mains input socket *
200mm (8") Ultra Long-throw Driver with heavy duty pressed chassis & magnet *
3 year manufacturers return to base warranty * Dimensions (WxHxD ) 278mm X 332mm X 278mm *
Weight 10.5kg (23.1 Ibs) *
Black Satin finish as standard with Real Wood Veneer finish an option at extra cost.


£349.00 (black or silver)
£399.00 (wood veneers)


==========

Reference 150

PICTURE

SPECIFICATIONS:
150watt DC-coupled Bi-Polar Amplifier *
Speaker and line level inputs with Gain Control Range 80dB *
Neutrik Speakon connectors (Gold Plated) (High level 100k ohm) *
Balanced (XLR) connectors (Gold Plated) (Low level 10k ohm) *
Unbalanced RCA (phono)(Gold Plated) & 3.5mm PC connectors (Low level 10k ohm) *
Sophisticated crossover circuit - variable increments between 30Hz and 120Hz *
Straight-through LFE Bypass filter switch * Phase Control infinitely adjustable between 0° and 180° *
Frequency response 13hz to 120hz * A.S.P. (Automatic Speaker Protection) *
D.A.M.P. (Digitally Accurate Microprocessor) *
Specially designed cabinet structure, volume, and configuration made from inert 18 & 30mm MDF *
Digital Display with power output meter and frequency setting * Switched fused IEC mains input socket *
270mm (10") Ultra Long-throw Driver with heavy duty pressed chassis & magnet *
3 year manufacturers return to base warranty * Dimensions (WxHxD ) 300mm X 358mm X 290mm *
Weight 14.65kg (32.3 Ibs) *
Black Satin finish as standard with Real Wood Veneer finish an option at extra cost.


£549.00 (black/silver)
£629.00 (wood veneers)


==========

Hope this is useful for some people. :)

MuFu.

Edit - Gawd... this looks like an ad, doesn't it?! Mods if you want to change anything go right ahead...

Edit - Marketing BS removed, heh.
 
MuFu...you have mail...BTW,are you in any way connected with MJA?
 
I have it on good authority that stock should be leaving MJ A soon - eta Friday. I promise to let people know what I think
 
No way a 10" driver in a small cab can reach 13hz. Porkies! And 10hz for the Reference 1? Not a chance!
 
Originally posted by MuFu
Please excuse the marketing BS

I think that excuses everything as the whole thing tells you absolutely nothing except that it has DAMP Technology which is very useful if your room suffers from a lot on condensation.
 
I'm guessing 13Hz is a -10dB or -12dB figure. Pretty redundant information, I agree. I don't see any reason why a 10" driver couldn't reproduce 13Hz though. It just wouldn't be distortion-free at any kind of useable level.

MuFu.
 
Originally posted by MuFu
I'm guessing 13Hz is a -10dB or -12dB figure.

It should be illegal to quote figures like that as they are grossly misleading. Why can't an organisation like BSI or DIN come up with a standard that can be used to compare like with like.

As it stands you may as well change the phrase "Frequency response 13hz to 120hz" and replace it with "Goes bloody low" as it has the same scientific basis.
 
Yeah, it's terrible isn't it? -3dB/-6dB figures are vastly more significant but only if *everybody* uses them and they are measured in the same conditions.

I take your point about the marketing BS - sorry, I literally just threw the leaflets in the scanner last week and at the time there was absolutely nothing on the net regarding these subs. I figured I'd post everything - at least the specs/prices are there.

MuFu.
 
This is the email I sent to MJ Acoustics...

"Can you please put up accurate information regarding the frequency response? No way a 10" driver in a small cabinet can reproduce 13hz, and again 10hz for the Reference is nonsense.

Even a 15" subwoofer cannot reproduce 10hz!"


and the reply..

"Hi Nathan, I was disappointed to receive your fiercely negative comments regarding our subwoofers as "nonsense".

Let me assure you that our drivers be it 8" or 10.5" can produce the frequencies we have published.

My apologies for wasting your and my time on trying to suggest a great system for you.

If you don't think that these drivers or even a 15" can produce such frequencies, then whatever I say to you, I will not be able to convince you that this is so. Therefore I shall take no more of your time."
 
The reply was considerably longer than the two word reply you would have got if you had sent that email to me.

Obviously diplomacy isn't one of your strengths :rolleyes:
 
The first email was considering my budget of £2000. I expect proper figures, not made up. Hey I know, let's say this subwoofer goes down to 8hz!!

When a company produces BS in their stats, I've every right to ask for proper figures, esp considering how much I'm going to spend.
 
There is someone around here who knows more about subwoofers than everyone else on here combined but unfortunately he has to work for a living.

Later perhaps :rolleyes:
 
Originally posted by nathan_silly
This is the email I sent to MJ Acoustics...

"Can you please put up accurate information regarding the frequency response? No way a 10" driver in a small cabinet can reproduce 13hz, and again 10hz for the Reference is nonsense.

Even a 15" subwoofer cannot reproduce 10hz!"

Nathan - they can reproduce such frequencies. I think you are missing the point slightly. I also sent an e-mail:

When you say "Produces a superb low 13Hz..." regarding these subs, at what level and in what acoustic environment is that measurement taken? Don't you think that such information is redundant given the fact that other manufacturers quote much more useful -3dB and -6dB roll-off figures? I very much doubt that 13Hz can be reproduced at any kind of useable amplitude by either of these subs. =\

In response:

Hi paul, thanks for your comments regarding the -3 & -6dB figures. Indeed we do not publish these figures as we find them (unlike other manufacturers) irrelevant in a real world environment.

When using test tones and sweeps to gain such figures this is all very well, but dependent on what the input material is likely to be whilst in the end users hands, these figures are likely to be different.

Therefore, we feel that unless you're likely to listen to test tones all day, you will not appreciate the test lab figures we give you as a manufacturer.

Both the Ref 100 and Ref 150 can produce 13Hz, although inaudible, it can be felt.

I hope you appreciate our approach to subject.

No, not really. :D

MuFu.
Edit - sp.
 
Probably recieved hundreds of emails with the same question! Reason why he's a bit narked :D

Still you can't produce a subwoofer and not expect it be slated if poor results are found out - does that graph above (Dom H) show the subwoofer to be quite bad?- know it's the cheapest one, but SPL output seems pretty low. Am I reading it right?
 
How come we don't have the same discussions with regard to tweeters. I'm sure that there must be a few Hz difference between different makes at the top end but we don't make such a fuss about it.

It would appear likely that this particular sub manufacturer present their statistics in a way that shows it off to their advantage. What's new, don't they all do that. It's a trick that they learned from HM Government
 
Some amplifier companies don't- Krell for instance. Technics do- and you will able to notice inflated values straight away- less power into 4 Ohm load, one channel drive, 1khz test tone, with 1% THD etc.
 
I do feel that any manufacturer worth it's salt will be prepared to put it's equipment up for independent review,and either suffer the consequences or enjoy the results as published....nathan's point about Krell for instance is true,as they traditionally do much better than even the published spec suggests.
Speaker manufacturers should be able to do the same,and their goods should also stand independent review,whether subs or not are being discussed.
Certainly driver area,cabinet size,amplifier power and LF equalization all have their part to play,as anyone who's had a proper full range speaker system will agree with....the Linn Keltiks I had would go down to 20Hz flat,with appropriate power amps and active crossover settings....thats a trick not many purpose built subs will do!
 
Originally posted by alexs2
I do feel that any manufacturer worth it's salt will be prepared to put it's equipment up for independent review,and either suffer the consequences or enjoy the results as published

None of the AV magazines publish proper test figures anyway leaving it to some of the specialised hifi press instead
 
Originally posted by Billy Bob Smith
It would appear likely that this particular sub manufacturer present their statistics in a way that shows it off to their advantage. What's new, don't they all do that. It's a trick that they learned from HM Government

The big problem with MJA is that they do not qualify their figures at all - they just say "Yeah, the Pro 50 goes down to 15Hz".

Some are more respectable: M&K use +/-2dB, Velodyne +/-3dB (the "standard" measurement, if there is one), REL used to use +/-3dB but they have now gone to +/-6dB and, all of a sudden their 25Hz Q150/Q200 now drop to 17Hz! (Maybe the REL Marketing men got their way.

The worst offenders are Yamaha with a laughable -10dB figure but at least they admit to this - MJA don't give any supporting data making their claims worthless.

Matt.
 
Originally posted by MuFu
I'm guessing 13Hz is a -10dB or -12dB figure. Pretty redundant information, I agree. I don't see any reason why a 10" driver couldn't reproduce 13Hz though. It just wouldn't be distortion-free at any kind of useable level.

MuFu.

More Like -24dB at 12hz, 27Hz -6B and 33Hz at -3dB dont qoute me on this as this is from memory I'll try find the actual figures tommorrow.

By the way a half decent 12" drive unit with some LRC in a 50 to 60 Litre enclosure and a 300W amp behind it will produce say 20Hz -6dB so the above figures for an 8 inch drive unit and 50W amp are good but are still not 13Hz.

By the way REL publish -6dB Figures, are these anachoic??

Tom
 

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