JM Labs Sub Utopia

06-25-2004, 05:44 PM

Has anyone else checked this out in June's S&V magazine. they have an advertisement of a subwoofer thats capable of 128db spl @ 16hz. The price is of course $6,000.00. Has there been any independant test on this unit.

Rob Cranwell

Will d s · 06-25-2004, 11:39 PM

Check out thier website they have been reviewed in many magazines worldwide and are some of the best speakers in the world. Thier site is focal-fr.

Dustin B · 06-26-2004, 01:07 AM

There is absolutely no way that sub can meet that claimed spec. Looks to be very potent and capable of outgunning the majority of subs available today. But 128dB at 16hz is total BS.

I'd bet money it wouldn't even break 105dB at 16hz in a Nousaine test.

Craig Chase · 06-26-2004, 08:12 AM

Gentlemen: The Sub Utopia claims a peak of 128 dB is avaiable from the 1000 watt amp-16 inch driver-port...

It also claims 16 Hz extension.

It does NOT claim 128 dB @ 16 Hz...

Assuming an Anechoic situation, look at the numbers:

The B4+ will hit 114 dB outdoors at 16 Hz, in the two port open mode. This is with four drivers with a total of 452 square inches of surface, each with a better than two inch peak throw... or appx. 905^inches per stroke. (It will be smaller than this, because the 12 inch figure is the nominal diameter, not actual effective driver diameter, but we will also use the full 16 inch for the Sub Utopia).

The two ports open in the B4+ and the single port on the Sub Utopia are appx. the same area (Focal quotes based on the larger surface of the sub area, so use the same in the B4+)...

With the larger enclosure, looking at Theile/Small porting parameters, the B4+ would be at least equal to the Sub Utopia in its gain from porting.

So... For the Sub Utopia to hit 128 dB at 16 Hz, it would need to move a bit more than 20 times the air than would the B4+ for 114 dB...

If anyone cares to finish the math as to how a single 16 inch driver will move 18,000 ^3 inches per stroke....

06-26-2004, 08:22 AM

Craig I'am with you... The ad in S&V is deceiving with the wording in the sentence having you beleive that the measurement @16hz was 128db SPL. The web site say's this.

"the combined use of both a high efficiency 40cm (16”) driver and a 1000 Watts RMS BASH amplificator allows to obtain considerably high peaks, such as a pressure of 128dB at one meter".

Rob

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Craig Chase · 06-26-2004, 08:28 AM

Bob - And people accuse US of "SPL" mongering...

Nathan W. · 06-26-2004, 09:57 PM

Go HERE and read the very last paragraph. I wonder what frequency is the "...lowest part of the spectrum."

MikeDuke · 07-12-2004, 07:21 AM

I have heard this subwoofer at Soundex in phila. I have never heard bass like that in my life. True, I have not heard SVS or some other brands that are popular here in this forum, but it is a mighty impressive sub. Let me put it this way. Soundex had this sub in a smaller room first. In that room I watched the core. The bass was so strong that it was flexing the walls. Tust me. This puts out more then 105 db. Before you slam it, you should go and check one out. P.S I belive the utopia has a 4 inch peak through. Also there is very very very little distortion.
M.D

Dustin B · 07-12-2004, 08:34 PM

JMLabs makes great stuff. That sub will be a performer. Likely can hit 128dB, but just at some frequency over 30hz in a smaller room. I'd still bet money though that in Nousaine's >7000ft^3 room following his measuring standards, it wouldn't break 105dB at 16hz.

And for the money it will cost, there are many other routes I'd take for equal or better performance. But for some it will be the right sub and a very good one at that.

dave alan · 07-12-2004, 10:22 PM

I agree with DustinB. The driver would have to be 99 dB efficient @ 1W/1M, anechoically (which I bet money it ain't, and even then, you'd be suckin' the life outta a 1,000 watt amp), so it ain't gonna hit 128 dB at any frequency without room gain. And...what room with what placement?

Specs without qualifications are just useless numbers. Makes me not like the sub without even hearing it.

Some Companies publish no numbers, most others publish misleading nonsense.

I want you to run to the window, right now, and open it and scream..."I'm not gonna take it anymore!"

Craig Chase · 07-12-2004, 10:31 PM

Now THAT was funny...