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MFW-15 subwoofer review

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4 replies to this topic

#1 of 5 OFFLINE   Vaughan Odendaal

Vaughan Odendaal

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Posted July 31 2008 - 10:53 AM


Finally, done. It has taken me some time to complete this review as there were a few snags here and there that ultimately prevented me from testing both subwoofers but I am happy to report that I've tested both units and I'm impressed.

For those that don't know me, I'm goneten from AVSforum. I live in the sunny side of South Africa, Cape Town and in my neck of the woods, finding a decent subwoofer is a rather difficult affair. Believe me.

I suppose a decent subwoofer is subjective by definition but I expect decent output down to 20 hz with low distortion as a prerequisite. Finding a subwoofer that can meet those requirements is not that difficult in itself but the prices over here are astronomically high. I knew I had my work cut out for me.

Now, truth be told, about six months ago I had never even heard of this company called "Perpetual Technologies". Just another online subwoofer manufacturer I thought. But the MFW-15 pegged my interest. Like many, I decided to "jump the gun" and order based on Craigsub's review.

It was a difficult decision for me based on the fact that shipping is extremely expensive to ship to South Africa. It was even more difficult to convince the sig-(ahem)-nificant other to allow me to purchase a second MFW-15. Except she didn't "let me". I essentially conned her into believing I had won the second MFW-15 in a raffle. Kudos to Sean for drawing up the pro-forma. I owe you one.

Fast forward a couple dozen email exchanges with Mark and I had a pair of satin black MFW-15's headed my way. Many thanks to Mark for allowing this transaction to take place. I believe I'm the first foreigner to review these units so I'm excited about that as well.

I was all giddy with excitement when I got the phone call from Bax and learned that my shipment would be delivered later that afternoon (3 months later. . .) I finally got home and I couldn't believe my eyes when I saw the size of the boxes.

Impressive. I decided not to post pictures of the boxes because, well, I tore them up pretty badly in my excitement. Posted Image

Fit and Finish.

These subwoofers are extraordinarily well built, extremely non-resonant and sonically inert.

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I chose satin black because it blends in well with the rest of my gear. I would have chosen the diamond finish if it was available but I'm definitely not complaining. In person the finish has a very smooth, luxurious look and feel. Bottom line is that I was really pleased with the overall finish : (below)

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Moving one MFW-15 around the house was a chore for me. Moving two of them was a task in itself but it was worth it in the end.

My system :

Jamo Concert 803 front speakers, Concert 80 center, Concert 80 dipoles, old Yamaha AV receiver and a Velodyne SMS-1. All equipment is calibrated to equal levels with the RS meter. All speakers are set to small, DRC (dynamics range control) set to no/off, 80 hz crossover.

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The MFW-15 has it's own LFE input which bypasses the low pass filter in the subwoofer to avoid cascading of both filters. As a matter of interest, I tested using both low pass filters engaged to see what changes were made to the frequency response up to the crossover point and it was minimal, however, there was a depression below the crossover point which, at first, you wouldn't suspect.

The phase shift that occured was lower than expected as it affected output response in the 40-50 hz region. Nevertheless, I only used the LFE input for testing. Phase was set to 0 on both subwoofers and verified with both SMS-1 and Room EQ wizard. A simple Y-splitter was used to connect up both subwoofers to the subwoofer pre-out jack at the AVR side.

(Note; I tried co-locating both units. If a subwoofer is positioned to within 1/4 wavelength the sound waves will acoustically couple and one can achieve a maximum 6 dB increase in output. Final placement of subwoofers is approximately 4 meters apart. Even still, coupling at 1/4 wavelength is largely intact at low frequencies, simply not up to the x-over point.)

I calibrated all main speakers to 75 dB's using pink noise and using the subwoofer warble tone 71 dB's per sub, which, after setting the gain levels correctly on both units independently, yielded a 74-75 dB reading. I simply dialed it back a dB and I was set.

The in-room frequency response showed typical anomalies caused by room acoustics. I used my SMS-1 to optimize the frequency response, taming moderate room mode peaks.

I positioned the first MFW-15 behind the couch. Testing confirmed a major null centered around 43-44 hz : (below).

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Since then I repositioned my couch and I managed to reduce the effect of the null but not by much. I then positioned the subwoofer besides my main speakers and the null was largely mitigated. The peak I had before between 48-52 hz has been cut using the SMS-1 and it's looking much better.

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The subwoofer distance control was then used for further fine tuning. As you can see by the waterfall chart, decay times below 40 hz is pretty poor but keep in mind that my room has no treatment to speak of, no bass traps, nothing. I am definitely in need of bass traps.

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With movies :

I tested most material at -5 from reference. Much to my dismay, I was not able to take peak output readings at the listening position as I did get some complaints from several neighbors. Posted Image

A film I like to use on occasion that has nice deep bass extension is the Incredibles.

I used to own an SVS SVS PB10-ISD and it was a good little subwoofer that managed to dig down to 20 hz at relatively high levels. But not like this. Heck, leaving only one MFW-15 on for the duration of the testing was a substantial difference in output, extension and low compression.

Dynamics are fantastic. The bass just hits you and disappears. With a single MFW-15 there was a nice percussive hit upon the initial train impact on Chapter 1 where Mr Incredible braces for the train impact.

I could just increase the volume louder and louder with no perceivable compression. It just kept on getting louder. Turning the second MFW-15 on and I could feel each track lifting and breaking under Mr. Incredible’s feet. The initial train impact hit my chest hard.

Another great bass sequence is when Syndrome traps Mr. Incredible with his zero-point force Field. Lots of signal content in the 35 Hz region, with sub-harmonics at 17 Hz. The MFW-15's gave me a very exciting infrasonic undercurrent on this scene, sending tingles through the room.

Next up was Master and Commander, Chapter 4. Very loud, very deep and very clean. The initial impact of the cannon fire hit my chest and caused my wall unit to rattle. Bass extension was very good indeed. I did, however, apply a filter at 15 hz using the SMS-1 and upped the levels by 4 dB's to create a somewhat flatter curve.

I have not tried WOTW or Pulse with dual MFW-15's but I will as soon as I get more time. Flight Of The Phoenix is another film that I used that has ample infrasonic content. The storm turbulence sequence (0:13:52-56) easily pressurized my room and realistically created the sensation of plane buffeting.

Probably the best scene with the biggest wow factor is when the plane rolls upside down. This sound effect contains a very high amplitude signal at 35 Hz which last for about 5-6 seconds or so. My MFW-15's sounded spectacular on this scene with no signs of compression.

With music :

Some of my music demos are old but they still prove very effective for testing. Two Against Nature – Steely Dan, Giant Records, 2000. The track "Gaslighting Abie" opens with a well-recorded bass kick drum, and the MFW-15 sounded tight and percussive, with no slop or overhang.

Bassist Tom Barney shows off with some complex and fast finger work and the MFW-15 easily kept pace, never blurring the notes and always sounding articulate.

Sound Hound Classical Organ CD, Artist Unknown, 2003. Now this is interesting. I couldn’t resist breaking out the infamous “Sound Hound” Classical Organ CD.

Dual MFW-15's hit even the deepest (17 Hz) notes with authority, perfectly tracking subtle changes in air pressure, bringing impressive realism to this difficult recording. Even at chair massaging playback levels, I heard no audible doubling, just pristine infrasonic bass.

Underworld soundtrack - Lakeshore Records, 2003 "Renholder's Now I Know" features an ultra deep bass line centered at 23 Hz (I think) with bass extending to 15 hz in certain portions. Dual MFW-15's were amazing on this track. They providing a palpable sense of pressure in the room, easily conveying the presence of infrasonics.

Conclusion :

What can I say, I'm impressed. Throughout my subjective evaluation, both subwoofers always remained extremely well behaved. I never managed to cause either MFW-15 to falter or generated even a hint of audible doubling or cabinet rattle. This is one heavy duty subwoofer.

Many thanks to Mark for making a great product. You obviously put a lot of work into the subwoofer and it shows. I've heard my fair share of high performance subwoofers and for the money I spent, there is nothing and I mean nothing that can come close to this.

I waited a few months to get these subwoofers and for some that might be too long to wait. In my opinion it was well worth waiting for. Thanks.


#2 of 5 OFFLINE   hodedofome


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Posted August 01 2008 - 06:36 AM

Excellent review, graphs, and setup. It looks very nice and I'm sure sounds even better. Thanks for sharing.

#3 of 5 OFFLINE   Vaughan Odendaal

Vaughan Odendaal

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Posted August 02 2008 - 01:48 AM

Originally Posted by hodedofome
Excellent review, graphs, and setup. It looks very nice and I'm sure sounds even better. Thanks for sharing.

Thank you for the kind words. FYI, I just ordered four GIK tri-traps and six Ready Acoustic 4" panels so I'm excited about that. I'll post my impressions on the bass traps with before and after measurements when I get them.


#4 of 5 OFFLINE   Vin_G


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Posted August 07 2008 - 06:22 AM

Right on Vaughan. I also purchased dual MWF-15's in Moho. Very thick Veneer cover. Looks like actual plank wood on there.

I have not yet set them up in my dedicated home theater as I have not finished construction, but I did try them out in my living room and wow! I can't play them there because the neighbors complain way too much so I will wait until my sound-proofed Home Theater is complete in about 2 weeks.

I will need your advice on setup as I too bought the SMS-1, but I don't know how to use an Audyssey EQ on my new Onkyo amp with it. I will ask you off line, but good review.

#5 of 5 OFFLINE   Vin_G


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Posted February 02 2009 - 10:49 AM


I have everything hooked up with Audyssey and Velodyne and works great. Much better with Velodyne in conjunction with Audyssey.