Review - MJ Acoustics Pro 50 Subwoofer

[Dom H]

I've always left purchasing a sub for my 5.1 (music/film/gaming) system, not sure why maybe because I thought one wouldn't fit, would be too expensive for a good one or maybe because the only subs I have experience of were car audio and HT sub/sat systems.

Budget was upto £500 (preferably around 3 though) I had shortlisted the Rel Q50, Pro50 and the CHT-10. Measuring up the rel and velodyne would *just* fit, placement would be restricted to the corner also whereas the Pro50 would comfortably fit behind my front left b&w 602.

I knew all 3 were great subs, I had faith in uncle erics opinons that the cht-10 would perform, plus the Q50 would probably be the best bet from the rel camp. After reading some more particularly glowing reviews (and chatting to the guys at hifijunkies) plus the size issue, I decided to plump for the Pro50 in black.

Hifijunkies were superb (I really can't rate these guys enough) all through the order, and while they didn't have any in stock the day I ordered some came in the day after and arrived on my door the next day.

Out of the box it comes, not expecting much from the povety spec black finish but it looks superb in the high gloss piano black finish. Controls feel very nice, nice switchgear, the whole unit feels very well made.

Plug in the power and phono cable from the 3802 leaving all the knobs at their default position I fire up some Black Sunday. I'm greeted with big bouncy bass more akin to the trunk of a corsa. Ok time to break out the SPL meter.

After being a little nervous of the sub test tone noise I finally get all levels calibrated. I remember some saying to have the sub at maximum gain and adjust on the amp. Well with the denon on it's lowest setting I adjust the sub gain slowly until the meter shows me what I want to see. It finished with the sub gain at about 85% and the denon on it's lowest -12dB. Adjusted the phase to 90 as instructed for downfiring subs in the manual and left it at that. The manual states 'at one end' the crossover control is bypassed, I presume this meant it's default lowest setting of 40Hz. All speakers now set to small with an 80Hz setting.

I'll forward on now until last night when I gave the sub it's first real work out, Monsters Inc dvd. I was well pleased with my setup, low frequencies blended perfectly with the 602's giving the impression of a single, low reaching speaker. As others have commented one of the first things I noticed was not the bass but the midrange seemed to get a slight boost in presence.

Back to the film, the first real indication of the sub doing it's job were Sully's thumping footsteps which sounded great. Everything sounded very tight and controlled, not a hint of flabbiness. They kept pace perfectly with the 602's.

***tiny weeny monsters inc. spoiler ahead***

The part where boo, the little girl started to wail causing the power to go mad made me nervous. Suddenly there's this big blast of bass, getting wilder and wilder as the kid screams, I was just about to reach for the volume control (-6dB dts) as I thought such a small sub will surely croak under the pressure. Not a thing, no flapping, slapping or any sort of distortion, just rattling doors and big clean bass. I was well impressed to say the least, especially as the pro50 weighs in at a modest 8' and a 'measley' 50 watts.

Musically so far the Pro50 has seen some Nelly, Cyrpress Hill and a touch of Eminem. I think the best way to describe it's musical abilites is very punchy, tight and definitely not flabby.

In short...I love it.

 

[uncle eric]

Dom,
I concur. This is a nice little sub thats great as the first step up the home theatre ladder. The MJ's 8" driver coupled with its 50watt amp doesn't pretend to do anything it cant, unlike some. It does its job well.
Happy listening.
Eric

 

[monkeyWRENCH]

OK, I'm convinced! HiFiJunkies have it for £300... is that the cheapest?

 

[Dom H]

I think so, they have just got more in. Tell em I sent you

Don't fret the 8' and 50watts, as I say in the review watching Monsters Inc at (if my maths serves me correct) 103dB, 2dB shy of dolby reference provides the lows with no noticable distortion.

I'd take a wild guess that in my small room 25Hz was achievable at or near reference level, I can imagine it tails off steeply after that.

The main thing is what range it does, it seems to do very well. I'd take more precision over extension.

If anyone (eric?) can give me some (safe!) steps to recreate a frequency curve using an spl meter and a cd writer/tone generater I'll see what it's capable of.

Dom.

 

[Madskilzz]

Auditioned a Rel Quake and a MJA Pro 50 this weekend, Eric you hit the nail on the head. The REL is an unruly little beast that just tries to do too much for it's small dimensions. Setting it up proved tiresome i just could not get the thing to blend in with my main speakers. The MJA Pro 50 in comparison was a joy to setup; it took no time at all to get a smooth sounding bassline.

Fast forward around seven hours of playing every demo scene in my dvd collection, without food and missing the England match. Good job my neighbours were out all day, I did take him along to my initial demo at Sevenoaks, can't ask for better neighbours.
Four hours into my session the Rel was boxed up and out the door. Maybe it just didn't work in my living room, greater patience would probably achieve a better sound but it just could not compete with the Pro 50 for all round sound quality. The next three hours was spent fine tuning and enjoying what the MJA sub had to offer.

Final Verdict

The Rel has the power but not the control, my first demo with a Rel sub left me disappointed, some may like it's aggressive nature but it proved tiresome.

Hats off to MJA Pro 50 it's cheaper, and less powerful than the Rel but still shook my living room, opening credits of Final Fantasy sounded damn good. I've placed an order for one this afternoon .

Battle of the "wood veneered shoeboxes" (uncle eric's analogy) goes to the Pro 50 4th round stoppage.

Mark

 

[Brox]

Uncle Eric - for interest how would a Pro 50 compare with my Kef 20B?

 

Isn't the 150WATT Velodyne CHT10 only £325????
Surely thats better than any of these budget jobs. No offence boys.

 

[Madskilzz]

No offence taken

The size and look of the Velodyne sub made it a total non starter, WAF played a major part in which subs I would audition. A big ol' black speaker box would not go down to well in my lounge, but a wood veneered shoe box is a different story.

I'm under no illusions that the Velodyne Cht-10 would whip most subs under £500.

Hope that's answered your question.

Mark

By the way have you heard the MJA Pro 50?

 

[Adele]

I'm absolutely delighted to hear that the pro 50 sub has impressed you Dom as I've just ordered one (cherry finish) from HiFiJunkies to be delivered this Saturday (along with an Ixos sub lead and hopefully a Multi Region Denon 2800 Mk2 DVD player - whoohoo!)

I wasn't sure whether or not to buy a sub at all (I've got a Denon 3802 AVR and Monitor Audio Silver 8i/10i/fxi setup) as my front speakers are quite weighty, but I couldn't help but feel that my system was still lacking that extra ooomph!

Should I set ALL speakers to small on my Denon 3802? Is there any argument in favour of keeping the 8i's large and just having the centre & rears small?

Glad to read your thread Dom as I was having second thoughts after I ordered about whether I should have just went for a REL.

Cheers,
Adele.

 

[Matt F]

Originally posted by Adele
Should I set ALL speakers to small on my Denon 3802? Is there any argument in favour of keeping the 8i's large and just having the centre & rears small?

It's best to experiment with the large/small settings to see which sounds best to you. However, as the 8i's drop down to 35Hz (according to Monitor Audio) then I would suggest they will work well set to "large", with the centre and rears set to "small".

Matt.

 

[Nobber22]

Originally posted by Matt F


However, as the 8i's drop down to 35Hz (according to Monitor Audio) then I would suggest they will work well set to "large", with the centre and rears set to "small".

Matt.

I understand the logic behind bass depth and large/small, but how does one get a uniform front-soundstage (which is what we are told is ideal) when the fronts are set to large and the centre set to small? Am I missing something regarding output from each of the 3 front speakers and matching levels?

 

[timothyw]

Originally posted by Dom H
The manual states 'at one end' the crossover control is bypassed, I presume this meant it's default lowest setting of 40Hz. All speakers now set to small with an 80Hz setting.

I would have thought that the crossover bypass would be at the other extremity of the crossover setting- it might be an idea to check this with some test tones, between 30 and 100 hz. I would be suprised if the crossover was disabled at its lowest setting, even if this was the default it arrived with.

 

[dfield2000]

I got my Pro 50 at sevenoaks and I managed to get them to knock off £40 from their original £300 asking price. This suggests that there is a bit of a mark up on these so it might be worth doing a bit a haggle first.

 

[Matt F]

Originally posted by Nobber22


I understand the logic behind bass depth and large/small, but how does one get a uniform front-soundstage (which is what we are told is ideal) when the fronts are set to large and the centre set to small? Am I missing something regarding output from each of the 3 front speakers and matching levels?

The only way to get a truly uniform front soundstage is to use three identical speakers, preferably all in the same plane e.g. all vertical. This is not always practical because of where the centre speaker has to go (underneath or on top of the TV) so even with three identical speakers, the centre often ends up on its side - this is still a near ideal set up and all speakers would be set to large or small (probably the latter) as they are identical and can handle the same frequencies.

Many people, however, opt for floorstanders as their left and right pair. This can be for aesthetic reasons but also because a lot of people like to listen to 2 channel music through a pair of "fullish" range floorstanding speakers (or large stand mount speakers) without using a subwoofer.

This is where the compromise comes in because in most cases there simply isn't the room to use another floorstanding or large stand mount speaker for centre duties because, as I said, the TV is in the way. So, dedicated centre speakers were invented and whilst a few can reach down to 50Hz, a lot of them don't do much below 80Hz which ties in with the standard "small" speaker setting on the majority of AV amps.

Some amps/processors allow different crossover settings e.g. 50Hz, 80Hz, 100Hz, 120Hz - I believe the Denon 3802 offers 80, 100 and 120Hz. Adele's speakers have the following lower frequency limits (according to Monitor Audio):
8i (fronts) = 35Hz
10i (centre) = 48Hz
Fxi (rears) = 55Hz

Now, the centre and rears aren't really capable of handling a full range signal so, in the absence of a 50Hz crossover (which might have worked quite well) an 80Hz setting will do just fine.

The front 8i's, however, can handle a lot more than this - they can IMO happily handle a full range signal and that is why I would suggest they be set to large to start with. They may sound better set to "small" but I reckon that the overall sound will be better with them handling lower frequencies than 80Hz - difficult to describe why other than to say that by doing this the mid-bass (40-80Hz) will be handled by both the sub and the fronts and will be "spread around" a bit better.

As ever, experimentation is the key. Adele needs to try both the large and small settings and see which she prefers - that then is the right setting for her. I think they'll sound better set to large but that's just my opinion - I may well be wrong.

Finally, as for the output from the 3 front speakers (and the rears and the sub for that matter), regardless of whether they are being set to large or small, they should all be calibrated using an SPL meter.

Matt.

 

[monkeyWRENCH]

Dom H, after reading your excellent review, I have just placed an order with HiFiJunkies

I Hope it sounds as good as you say it does (I have 1802 and Wharfedale Diamond speakers)

 

[Brox]

Does anyone know how low the Pro 50 goes at +/- 3db, I can't find this information.

Cheers

 

[Dom H]

Here is a Excel sheet of recorded levels using an SPL meter of my Pro 50.

Pro 50 <click on Pro 50 then save or open>


note. I usually put up some temporary wall treatment when watching films, this was recorded without. Small room acoustics, dontcha' just love 'em?


btw setting the x-over on the sub to 240Hz activates the bypss (just email mja)

 

[monkeyWRENCH]

Dom H, just a quick question - does the pro 50 come with rubber feet? I didn't order any extra spikes and I have wooden floor, so I'm worried that it might start to move around when it's in operation.

 

[Dom H]

Yes they are about 2'

 

[Brox]

Dom H - I can't find the details about the sub in your link!

Can you give me some more info on how to get there.

Thanks

 

[uncle eric]

Originally posted by Brox
Does anyone know how low the Pro 50 goes at +/- 3db, I can't find this information.
Cheers

Brox,
Don't expect this sub to do high db's at subterranean depths. A small sub in a small box of low cubic volume paired by a small 50 watt amp isn't going to do a great deal. Yes, its pretty decent and better than the Yamaha and Wharfdale cheapies that are around but is murdered stone dead by a £325 pound sub that should cost much more. The Velodyne CHT-10 is made by one of the pioneers of sub makers and can't be touched for anything near that price. With respect guys, once you've heard "real" bass, you'll know what I'm talking about.
Regards
Eric

 

[Dom H]

Bronx click on that link, then click on the little page icon labled 'Pro 50' it'll then ask you to save it or just open it. Click open to view.

Eric what do you make of these figures, not too sure what to make of them, why doesn't it tail off around 25Hz?


Dom.

 

[Brox]

Thanks for your reply Eric but I suspect Like myself Dom H wanted a very small sub, that's why I went for the 20B

Otherwise I would have got a Velodyne in the power buy or a Rel q100 or something like that.

Since I havn't heard many subs i'm always interested to know how they sound against mine as that's the only reference I have.

 

[uncle eric]

Brox,
IMO, You will not gain anything by replacing your 20B with an MJ50.
Regards
Eric

 

[MikeK]

Originally posted by uncle eric

The Velodyne CHT-10 is made by one of the pioneers of sub makers and can't be touched for anything near that price.
Regards
Eric

Unless you go DIY