Hi guys,
I've posted a review of my dual MFW-15 subwoofers a while back on several audio forums (AVS, Audioholics and HomeTheaterForum) but I never posted it here. So I thought I would share my review with you guys with some updated graphs that were not shown in the original review and you can tell me what you think. I've also added a few extra comments to elaborate a bit more on some of the finer points.
"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.
Fit and Finish.
These subwoofers are extraordinarily well built, extremely non-resonant and sonically inert. Each cabinet weighs in at around 48 kg's.
I chose satin black because it blends in with the rest of my gear. I think I made the right choice.
I was really pleased with the overall finish : (below)
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.
(Edit -- since I've taken this picture I've added the Onkyo SR-876 receiver and added B&W FS-700 stands)
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 3.5 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 70 dB's per sub, which, after setting the gain levels correctly on both units independantly, yielded a 74 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 initially positioned the first MFW-15 behind the couch. Testing confirmed a major null centered around 43-44 hz. Since then I repositioned my couch and I managed to reduce the effect of the null but not by much.
The subwoofer distance control was used to help alleviate this but did not help much. Phase controls had little effect either.
I then positioned the unit in front of the room besides the left main speaker and got a flatter response but the null persisted :
The subwoofer distance control was then used for further fine tuning. As you can see by the waterfall chart (below), 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. As I've mentioned before, the rooms acoustics will ultimately determine how a speaker or subwoofer performs. I am definitely in need of bass traps. ;D Also keep in mind that the SMS-1 had a subsonic limiter engaged and the initial software prematurely rolled bass off from 15 Hz and below. My software has since been upgraded and subsonic limiter has been disabled (in the final graph).
(Edit -- I've since ordered 4 GIK tri-traps for bass trapping in addition to (3) 244 panels for first reflection duty and (6) Ready Acoustic bags to build more panels for extra control. Review pending. . )
Here is an updated measurement with both subwoofers calibrated and EQ'ed with SMS-1 and here you can see the real power of adding a second subwoofer to fill in where the nulls take place. Heck, moving both subwoofers simply inches either way changed their FR curve and after some fiddling :
Still not a perfect response but a huge improvement considering no room treatment. There are still one or two peaks (especially one at 60 Hz) but after listening it adds a extra bit of fullness which I prefer and I still have a few filters left in the SMS-1 to cut the peaks if I want. The real issues are the decay times which are determined by the rooms dimensions, the composition of the wall (stiffness) and wall to wall spacings.
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. :
A film I like to use on occasion that has nice deep bass extension is the Incredibles.
I used to own an 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. Using single frequency tones a single MFW just about managed to pressurize my living room using a 13 Hz tone. This was the lower limit. No commercial sub I know (within a R30k price bracket) can do this. Often you'll have expensive subwoofers make claims of deep bass extension below 20 Hz and not actually deliver on those specs. Well this sub delivers !
Dynamics are fantastic. The bass just hits you and disappears. I think the rigidity of the cabinet has a big role to play here. 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. I often use this sequence at my shop for demoing systems for clients. The initial impact of the cannon fire hit my chest and caused my wall unit to rattle. Bass extension was very good.
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. It's pretty scary what two of these subs can do.
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. The downside is that it's big. The pictures you see don't really show the size of these things properly.
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"
That's it. Let me know what you think.
Cheers.
Regards,
I've posted a review of my dual MFW-15 subwoofers a while back on several audio forums (AVS, Audioholics and HomeTheaterForum) but I never posted it here. So I thought I would share my review with you guys with some updated graphs that were not shown in the original review and you can tell me what you think. I've also added a few extra comments to elaborate a bit more on some of the finer points.
"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.
Fit and Finish.
These subwoofers are extraordinarily well built, extremely non-resonant and sonically inert. Each cabinet weighs in at around 48 kg's.
I chose satin black because it blends in with the rest of my gear. I think I made the right choice.
I was really pleased with the overall finish : (below)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.
(Edit -- since I've taken this picture I've added the Onkyo SR-876 receiver and added B&W FS-700 stands)
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 3.5 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 70 dB's per sub, which, after setting the gain levels correctly on both units independantly, yielded a 74 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 initially positioned the first MFW-15 behind the couch. Testing confirmed a major null centered around 43-44 hz. Since then I repositioned my couch and I managed to reduce the effect of the null but not by much.
The subwoofer distance control was used to help alleviate this but did not help much. Phase controls had little effect either.
I then positioned the unit in front of the room besides the left main speaker and got a flatter response but the null persisted :
The subwoofer distance control was then used for further fine tuning. As you can see by the waterfall chart (below), 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. As I've mentioned before, the rooms acoustics will ultimately determine how a speaker or subwoofer performs. I am definitely in need of bass traps. ;D Also keep in mind that the SMS-1 had a subsonic limiter engaged and the initial software prematurely rolled bass off from 15 Hz and below. My software has since been upgraded and subsonic limiter has been disabled (in the final graph).
(Edit -- I've since ordered 4 GIK tri-traps for bass trapping in addition to (3) 244 panels for first reflection duty and (6) Ready Acoustic bags to build more panels for extra control. Review pending. . )
Here is an updated measurement with both subwoofers calibrated and EQ'ed with SMS-1 and here you can see the real power of adding a second subwoofer to fill in where the nulls take place. Heck, moving both subwoofers simply inches either way changed their FR curve and after some fiddling :
Still not a perfect response but a huge improvement considering no room treatment. There are still one or two peaks (especially one at 60 Hz) but after listening it adds a extra bit of fullness which I prefer and I still have a few filters left in the SMS-1 to cut the peaks if I want. The real issues are the decay times which are determined by the rooms dimensions, the composition of the wall (stiffness) and wall to wall spacings.
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. :
A film I like to use on occasion that has nice deep bass extension is the Incredibles.
I used to own an 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. Using single frequency tones a single MFW just about managed to pressurize my living room using a 13 Hz tone. This was the lower limit. No commercial sub I know (within a R30k price bracket) can do this. Often you'll have expensive subwoofers make claims of deep bass extension below 20 Hz and not actually deliver on those specs. Well this sub delivers !
Dynamics are fantastic. The bass just hits you and disappears. I think the rigidity of the cabinet has a big role to play here. 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. I often use this sequence at my shop for demoing systems for clients. The initial impact of the cannon fire hit my chest and caused my wall unit to rattle. Bass extension was very good.
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. It's pretty scary what two of these subs can do.
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. The downside is that it's big. The pictures you see don't really show the size of these things properly.
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"
That's it. Let me know what you think.
Cheers.
Regards,
