Dual Mass 2012 pitted against a Velodyne FSR15, check out the results...

Discussion in 'Archived Threads 2001-2004' started by TerryC, Feb 21, 2001.

  1. TerryC

    TerryC Stunt Coordinator

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    I posted this in the Hometheater Hardware forum but the Dual Mass results will probably be of interest in this DIY section as well.
    I finally got around to the Mass/Velo comparison with the help of Rich and all I have to say is, oh my god! I'm a measurement kind of guy so I'll cut to the chase and present the info.
    Velo is a standard FSR-15 .(BTW this sub currently is currently in the number five spot for measured bass performance by the master of bass Tom Nousiane) See more of his comparisons here.
    Dual Mass is a DIY that uses Dual 12" Audiomoible Mass 2012 drivers in a 11ft3(11 cubic foot enclosure) with its ports tuned way down to 17hz. Subs were switched out and placed in the same location for all tests. These are very close ralatives to the Aerial SW12 Drivers but instead of 15mm of each way travel they have 19mm! See more of the Aerial here.
    Processor used was a Meridian 861, FSR15 used its internal amp and the Dual Mass used a Crown K1 that puts out 1400W. No EQ was used but the Meridian was using a 58hz low pass crossover on the sub channel. Mic used was a 150db LinearX M51 and software was SpectraPlus. Testing room is about 7500-8000ft3.
    Here is a pic of the cast of characters along with one of the Meridian DSP6000 mains that where tuned off for the testing so they wouldn't interfere with the test results. http://terryctheater.tripod.com/velomassmerridian.jpg
    On to the test results:
    We first decided to use a a semi quite frequency sweep at 1 meter to see how they performed. http://terryctheater.tripod.com/fsrmass1meter.jpg
    Red- FSR 15
    Pink- Dual Mass
    As you can see, both subs performed fairly equal with the exception of the Mass playing lower. There are some small differences at other frequencies which are caused by the different attributes of each sub along with the fact the FSR sits on the floor with one radiating surface while the Dual Mass also has one of its drivers located up top just over 4 feet up!
    Here is a balls to the wall Max SPL test taken at the seat 13ft away! http://terryctheater.tripod.com/128m...xspseatedl.jpg
    Red-Dual Mass
    Green-FSR15
    As you can see this is where it gets really interesting.
    (I'll explain an interesting tidbit for those that don't know how sub specs are accomplish after the next graph to help explain it.)
    As you can see at loud levels the Dual Mass is still relatively the same as when it was tested at a lower volume but the FSR is way different as it starts to role off the bottom end. In this test the Dual Mass absolutely annihilates the FSR15! Its about 20dB louder at 20hz!!! That's one heck of a difference and I was shocked to be honest I was thinking it would be about 6db to 10db. You can clearly see the FSR's limiters preventing the speaker from trying to produce frequencies at volumes it can't. This is a real eye opener at just how much the velo sub does this!
    Here is the limiter at work on the Velo taken at 1 meter: http://terryctheater.tripod.com/fsrlimiter.jpg
    Red-Velo 1 meter
    Pink-Dual Mass 1 meter
    Blue-Velo turned up louder 1 meter
    Green-Velo tuned up louder 1 meter
    In this test we used the first graph that was tested at one meter as a baseline but increased the volume on each of the two subsequent passes to show the limiter in action.
    As you can see the velo had decent extension at low volume. This is because the speaker is barely moving back and forth so it can produce a all of those frequencies. This is similar to how they spec speakers with 1 watt of power which doesn't even stress the speaker.
    Notice when we play it loud the bottom end disappears on the FSR15. This is because the speaker doesn't have the mechanical movement(back and forth movement) it would take to produce these low frequencies. The designers knew this when they made the speaker so they included a limiter which automatically cuts back the volume at those frequencies. This is a good thing as it protects the sub from damage but as you can see it makes a decent spec'd sub not even come near its spec frequency response at loud levels. IMHO they needed to use a better driver so they wouldn't have to do cut the info so early and as you can see in the case of the FSR15 it's about 28hz or so.
    That's the end of the testing.
    On a side note you will notice a little window in the graphs. This represents the combined reading of all the frequencies the way a Radio Shack meter would show. So for instance even though the mass on the line graph shows a high reading of about 115 to 116db at 53hz area it was actually showing a peak reading of 128.23db at 13 feet away! If you are trying to compare this to a rat shack meter this is the figure to use! Yes we reached 128db! We also did a comparison of how off the rat shack meter is at loud volumes and we did a test where the Rat shack meter read 116.5db and Spectra was showing 122db. I know this compares well with what Tom Vodhanel figured on his mic's as well.
    It was a lot of work and I hope some find the information insightful as to just how much a top performing sub can be off at higher volumes. It also shows how much of a killer system DIY can get you.
    Terry
     
  2. Pat

    Pat Agent

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    Terry,
    Great job!
    I love seeing great comparisons, especially when backed up by measurments [​IMG]
    That limiter really kicks in hard.
    Thanks for taking the time to do this and for sharing it.
    ------------------
    [​IMG] Pat's Page
     
  3. Bob Sorel

    Bob Sorel Stunt Coordinator

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    Terry, yet another excellent report! However, I was under the impression that the Velodyne F1800 was their top performer. I would be very curious to see how the dual Mass2012 sub compares to the Power15 from Stryke Audio.
    Here is an excerpt from the report on the Stryke site:
    For those who would like a
    comparison between other available
    home theater subwoofers we are
    providing the following results from
    TN's testing on the Velodyne®
    F1800 from the September 1997
    issue of Stereo Review. The article
    was entitled "How Big Is Big
    Enough." To the best of our
    knowledge, the F1800 has the
    highest average SPL and highest
    16Hz and 20Hz output of any
    production subwoofer measured by
    TN communications. This
    comparison should give a good idea
    as to the extreme levels of output
    achieved by the Power15. The
    results below compare the Power15
    to the F1800 in the 2136ft3 room.
    Average SPL 25Hz to 62Hz
    Velodyne F1800 - 112dB
    Stryke Power15 - 117.8dB
    SPL at 16Hz 10% distortion
    Velodyne F1800 - 102dB
    Stryke Power15 - 110.5dB
    SPL at 20Hz 10% distortion
    Velodyne F1800 - 106dB
    Stryke Power15 - 110.1dB
    Do you have any idea where the Power15 and F1800 would fit in with these 2 subs that you have just tested? Off hand it looks to me as if a single Power15 can outperform even a dual Mass2012, but maybe I am reading incorrectly.
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  4. TerryC

    TerryC Stunt Coordinator

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    Jack Gilvey, Bob, Pat,
    Thanks for the kind words guys.
    Bob, great eyes! I missed the 18" data and the few below it. I wouldn't doubt the FSR18 had the same drastic limiter at high volumes as well though.
    "Do you have any idea where the Power15 and F1800 would fit in with these 2 subs that you have just tested? Off hand it looks to me as if a single Power15 can outperform even a dual Mass2012, but maybe I am reading incorrectly."
    About the Stryke, this question came up long ago and Tom Vodhanel thought the Dual Mass's would beat a Stryke with Radiators or at least that would be the design he would pick.
    Tom Nousaine measured at 2 meters, we took these max SPL measurements at a 13' distance! Also you need to use the larger room size of Tom Nousaines info as Rich's room is even bigger than Tom's 7500ft3. Who knows where our results would have been at 6 feet? A lot louder that's for sure, but either way, this is like comparing a Ferrari to a Lamborghini, both are killers in their own right and will do all their owners proud.
    Two things I'm not sure of is Toms 10% distortion and and his 6.5cycle tone bursts at 1/3 centers. The 10% distortion baffles me as everything in the room at those volumes and frequencies rattles which has to affect the readings. I'm also not sure if the 6.5cycle bursts give louder or quieter readings over my regular frequency sweeps?
    Maybe Tom Vodhanel can clarify these two unkowns?
    Here is the Styke info: http://www.stryke.com/power15-res.htm
    Jack,
    I'm finally doing my Tempest test this weekend(sorry Dan W. its taken so long). Its a 8.5ft6 tuned to 20hz. Keep an eye out for the results. My hunch, it will compare very well to a single mass at half the price but twice the size which isn't an issue for many.
    Terry
     
  5. Jack Gilvey

    Jack Gilvey Producer

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  6. Bob Sorel

    Bob Sorel Stunt Coordinator

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  7. TerryC

    TerryC Stunt Coordinator

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    "Wow! Rich's room is bigger than 7500ft^3? That has got to be one huge room! "
    Yes is a dedicated theater room. Take a look at how much those two main speakers cost and his pre/pro, this is easily one of the better home theaters in the States, he even has a 11-13' screen! It's deceptively simple you don't realize the amount of money thats in it all.
    "If you have the time or the inclination, would you take the same measurements at 2 meters? I would be really curious to have an apples to apples comparison, assuming Rich's room is close enough in size to Tom Nousaine's (the 7500ft^3 results are graphed at the Stryke site). "
    I don't think they would compare still as they are totally different rooms. Also I'm not sure Rich will want to subject his body/room/sub to those frequencies and SPL's again. So in otherwords highly unlikely, sorry.
    'Regardless, it looks (or should I say sounds) like the Dual Mass2012 is a force to be reckoned with, and certainly one of the contenders for the "king of the hill" title! INCREDIBLE!!!"
    Yes as I've known all along this sub absolutely rocks. Tom Vodhanel thinks enough of this design(I built it on his recommendation) for his new SS subs.
    Terry
     
  8. Eric S

    Eric S Agent

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    Terry: Great work! Thanks for your efforts and time to share your findings with us! Makes me all the more proud that I chose a Mass 2012 for my sub (1 driver in half of the volume you have, tuned to about the same point)! I'm thinking that when I end up in a house, I need another Mass 2012 for the other corner...
    I'm really surprised to see how much the limiter affects the Velo. Their reputation and reviews would suggest that the limiter would not make that substantial of a difference in the actual output in the low bass.
     
  9. Mark Seaton

    Mark Seaton Supporting Actor

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    Mark Seaton
    The limiter in the Velodyne Servo subs, both FSR & HGS series, are the main offenders to sound quality. The subs will actually sound pretty good at lower levels or when oversized for a room. You would probably be suprised to see how many subs out there do employ some sort of limiting. This is the only way that Carver was able to make the Sunfire work. The sub IS flat to 20Hz, at 90dB/1m. As you ask the sub to do more, you will not get much more from 20Hz, but above 35Hz it will do around 120dB. Bag End is another company who's designs rely on limiters to work properly. In their case the limiting circuitry is much less offensive than in many other subs, and they have been praised as good sounding.
    This is one of the many reasons DIY subs can easily outperform retial subs which have to be reliable for general consumer use & abuse.
    As for the comparison to Tom Nousaine's tests, the 10% distortion issue is significant. The distortion charateristics of various designs and drivers can vary a good deal, and how much output you can get past the 10% distortion reading will vary. It will always be tough to compare absolute output levels from 2 sources unless things are truly anechoic, but relative comparisons are always great to see when done under the same conditions. The real Value of TN's data aren't the actual raw numbers, but more the ability reliably compare the data taken from each test.
    Mark Seaton
     
  10. Bob Sorel

    Bob Sorel Stunt Coordinator

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    Terry,
    Just so that people can get an idea of what a great value DIY sub building can be, can you give us an idea of the cost/performance factors involved? For instance, how much do the Vel FSR-15 and the F1800 cost, and what do you get for an amp with those 2 subs? How much did the dual Mass 2012 cost to build, and how much does a Crown K1 cost (and how much better of an amp is the K1 as compared to the typical plate amps)? I think a lot of people will be very surprised [​IMG]
    ------------------
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