SVS and $81 Sonosub

Discussion in 'Archived Threads 2001-2004' started by Jin E, Aug 11, 2001.

  1. Jin E

    Jin E Second Unit

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    The Contenders:
    [​IMG]
    Corner 1: SVS 25-31CS
    ~3.5 cubic foot 12-inch bass reflex passive subwoofers Tuned to 25hz
    Corner 2: $81 SonoSub
    1.9 cubic foot 10 inch bass reflex passive subwoofer tuned to 46hz
    My initial thoughts when I set up each sub individually was that the $81 was much more musical then the SVS. The SVS doesn't seem to produce the punch in the chest Hip-hop high frequency bass as well as the Sono did. My guess was that the small shorter throw 10" driver did a better job at the stuff 50hz and higher, and that it might be a good idea to cross the subs over at 50hz (with the $81 sono seeing a 50z high pass and the SVS seeing a 50hz low pass). Part of the reason for the test is to help me choose a crossover frequency.
    The Test Equipment
    -CEL-420 Noise Dosimeter
    ----Frequency Weighting: C
    ----Response: Slow
    -Bass Mekanic Power Tools (Test Disc)
    -RCA LDR600 Home Theater Series Laserdisc Player
    -Denon 2801 Audio Video Receiver
    -Kenwood KA8100 Integrated Amplifier
    The Test:
    The objective of the test was to measure the SPL at each specific frequency using the CEL-420 Noise Docimeter (borrowed from work, much more accurate then my RadioShack SPL meter). Both subs were run to the right channel of the Kenwood KA8100 with the 16hz Second order (12db/octive) Subsonic filter activated (SVS on channel B while the $81 sonosub was on channel A). I did this so that I could also compare the efficiency of each sub with the A-B switch while each sub is fed the same info from the same amp from the same source. The $81 Sonosub was located in the left corner of the room while the SVS stayed in the right corner.
    [​IMG]
    The sub level was calibrated to 80db using the Video Essentials using only the $80 Sonosub. Each test tone ran for 9 seconds with a 1 seconds pause in between. The test ran from 20hz to 80hz. Anyhoo... here are the results:
    [​IMG]
    As you can see the 12" SVS is MUCH more efficient then the 10" Sonosub. There is a very nasty dip between 49-56hz for the sonosub. I thought this was due to my placement but even moving out of the prime listening position 4-5 feet I only saw a 1-2db improvement.
    Now what bothers me is how the SVS tails off dramatically after 60hz. I'm not sure if this is something I can attribute to room placement. I've moved the SVS out and about all around it's corner but did not get much if any improvement in SPL in the 65-80hz range. At first I thought the SPL tailing off might have something to do with the low pass filter used in the Denon's 80hz crossover, but then again the $81 sonosub did not experience the same phenomenon. What do you guys think? Before I ran my tests I was considering low passing the SVS around 50hz and High Passing the $81 Sono at 50hz. After the test it looks like 60hz would be a more appropriate number.
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    -Jin
    My Theater
     
  2. TerryC

    TerryC Stunt Coordinator

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    Comparing subs in two different corners is worthless. If you want to compare the SVS to your DIY you need to test both in the same corner.
    Only good testing in different corners is if those corners are going to be the final resting place of each sub and you want to measure room esponse.
     
  3. Neil Joseph

    Neil Joseph Lead Actor

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    Real Name:
    Neil Joseph
  4. Jin E

    Jin E Second Unit

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    I left each respective sub in their own corner because this will be their final positions. I mainly did the test trying to find a good place to cross the subs over. I guess I was misleading with the title because this isn't a true head to head comparison, and was never ment to be. But even moving the SVS about the room could not keep it from dropping off after 65hz. Is this a trait of the sub or is it somehow just a trait of the room? I did a 20 second sine sweep from 20hz up to 100hz and you can see the SVS's SPL tail off up until the 80hz low pass Xover even when measured a couple of feet away sitting in the middle of the room. I will say the tail-off wasn't nearly as bas as what is shown in the graph when moved into the middle of the room, I got about 1.5-2 db higher towards 80hz.
    ------------------
    -Jin
    My Theater
     
  5. John Chow

    John Chow Second Unit

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    FWIW, I have a 20-39, and recently ran a frequency sweep from 200Hz to 20 Hz, and my SVS was virtually flat the whole way through except for a 5-8 dB peak at 120Hz and 55 Hz, probably due to room experience. I only had the output level at 70 dB, and measured with a Radio Shack SPL meter.
     
  6. Tom Vodhanel

    Tom Vodhanel Cinematographer

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    It's really tough to figure out room induced freq stuff via the internet.
    I think from about 50hz to about 80hz...the 25-31 has a slight rolloff...maybe 2-3dB(it's anechoic response measurement is on the SVS site---but I'm too lazy to check it )
    Factor in the Denon's LP will be -3dB/80hz...and that will account for about 6dB of the rolloff measured. Try running the sweeps again with the main speaker playing too. The mains should be producing a lot of energy down to the 60hz range...so you might see the overall resonse flatten out a bit.
    I like the DIY tube too....nice head.
    TerryC. Where've you been? Make parole huh [​IMG]
    TV
     
  7. Steve_D

    Steve_D Second Unit

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    For what its worth I have to jack the 63, 80, and 100 HZ sliders on my ART 351 with my SVS 16-46, BUT I had to do the same thing with my Citation 7.4 THX sub placed in the same corner. I assumed I was fighting both room effects and the Denon's (mine is a 3801) crossover. Now, with your post I'm thinking mostly room effects.
    In this range, since both the Sub and the mains are producing significant sound, it's real hard for me to stay relatively flat by just EQing the sub. I will say that even with speakers (Studio 40's) set to large I get a depression in this area so I'm pretty sure most of it is room effects.
    With the ART, at my prime listening position, I'm +- 6 db from 25-100 HZ. I don't record the 20 HZ or 15 since the RS meter is very inaccurate there so I don't trust it, even doing the correction of +6.4 db at 20 HZ.
    Thanks for the informative post...helps me with some of my issues I'm working on. I'm thinking of playing with crossover points also, 60 HZ was the exact value I had in mind.
    ------------------
    http://www.sdiver.org
    [Edited last by Steve_D on August 12, 2001 at 02:11 AM]
     
  8. Jin E

    Jin E Second Unit

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    I re-ran the tests with both subs moved into the middle of the room, with measurements taken 3 feet away. I obviously have a nasty hump at 80hz in the left corner... because moving it out made a difference of -7 db with the sonosub @ 80hz!!! I've seen 3-4db humps before... but -7db!!! So the Sonosub too tails off like the SVS... just not the the extent of the SVS. The $81 sonosub is down -6db from peak while the SVS is down over -12db over peak @ 80hz. Since I did all my tests with my main speakers off I decided to run some with the speakers on. With my main speakers on using only the SVS sub placed in the middle of the room the system response is down -5db from peak @ 80hz with a sweep from 50-200hz, while the Sono is basically flat (+-2db) within the same 60-200hz range. You guys have any advice on low passing/ high passing my subs? Good/ bad idea?
    ------------------
    -Jin
    My Theater
     
  9. John Chow

    John Chow Second Unit

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    Do you have any way to control the phase on your sub? I know with a friend's 20-39 PC, changing the phase made as much as a 5-10dB difference at certain frequencies.
     

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