Parametric Equalizer for subs

Discussion in 'Archived Threads 2001-2004' started by Tony Genovese, Mar 12, 2001.

  1. Tony Genovese

    Tony Genovese Supporting Actor

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    I have a pair of HSU TN1220 subs which I'm running with the HSU 500 watt amp. I am crossing over my full range mains at 80 hz using the crossover in my Lexicon DC-2 processor.
    I recently purchased an Infinity Bass Optimization kit which includes a sound pressure meter and a cd with 23 test tones from 20hz up to 100hz. I have a 9 db peak centered around 35hz that encompasses the following frequencies: 35, 38, 40 and 43.
    Would a parametric eq such as one of the Ranes, Behringers, or Symetrix's be of use in my situation? In room bass is up around 5 db in the 20 to 30 range. I'm wondering if peaks at these low frequencies are worth equalizing out.
    Thanks
     
  2. Tony Genovese

    Tony Genovese Supporting Actor

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    Here are the readings:
    100 74
    95 75
    90 76
    85 75
    80 76
    77 76
    72 78
    66 77
    63 76
    56 74
    52 74
    49 74
    46 76
    43 78
    40 82
    38 83
    35 82
    30 78
    26 77
    24 76
    22 76
    21 75
    20 75
    Behringer also makes a straight Parametric called the PEQ-2200 that can be had for around $150. Perhaps this would be easier to use than the Feedback Destroyer?
     
  3. Deane Johnson

    Deane Johnson Supporting Actor

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    The Behringer is actually quite simple, it just take a little while to learn what the controls do. The instruction book has a couple of mistakes in it which send you in the wrong direction. Once you know what those are, it gets simple.
    There are a lot of threads on the BFD because so many are being sold they can't keep up with the demand. Anytime many people start purchasing equipment, a lot of questions arise.
    To me, it would be a mistake to settle for something less over fear it's too complicated.
    By the way, it looks like your peak is centered on about 38 Hz, but with stepped tones it hard to be sure. The AVIA sweep works good since it hits every frequency, but it's a bit tricky to read the screen and your SPL meter at the same time.
    Just my thoughts.
    Deane
     
  4. Patrick Sun

    Patrick Sun Moderator
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    How far away are you measuring, and have you included the correction values for the SPL meter at low frequencies?
    ------------------
    PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; LDs
     
  5. Tony Genovese

    Tony Genovese Supporting Actor

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    I tried two sound pressure meters. The Radio Shack digital, and the Infinity RABOS which use LED's to show the level (a bit of a battery hog because of it). They both gave me the same results so I'm not sure what correction factor I have to use.
    I measured from the listening seat at head position.
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  6. Michael Robbins

    Michael Robbins Auditioning

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    Just an FYI from a little looking around lately re: parametric EQs, the story I get about Behringer is that they're a real flakey company...they keep moving their production facility. The FBD has terrific bang-for-buck but if you can't get one, it does us no good.
    The Rane PE-15 probably won't get you what you want because its 5 bands have fixed frequency sweeps on each band...(20Hz-300Hz)...(60Hz-1kHz)...(150Hz-2.5kHz)...(450Hz-8kHz)...(1kHz-20kHz) thus, you'd be limited to only 2 of the 5 bands for sub 80Hz adjusting, with only 1 below 60Hz...not real flexible. You have to step up to the PE-17 to get full adjustment from 10Hz-20kHz on each band (like the FBD)but it will cost ~$375 street, and its only mono.
    The Ashly PQX-571 looks good, 5 band parametric with fully adjustable frequency control on each band, bandwidth control to 0.05 octave..but it is mono, does not have memory settings, and streets for ~$288.
     
  7. Tom Vodhanel

    Tom Vodhanel Cinematographer

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    >>>You have to step up to the PE-17 to get full adjustment from 10Hz-20kHz on each band (like the FBD)but it will cost ~$375 street, and its only mono.
     
  8. Tony Genovese

    Tony Genovese Supporting Actor

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    I was actually thinking about the PEQ-2200 which is cheaper than the FBD and has 5 bands of parametric eq. It's mono.
     
  9. Tony Genovese

    Tony Genovese Supporting Actor

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    Well, nobody seems to have the PEQ-2200 so I guess it's time to consider either the 551, the PE-17 or the Ashly PQX-571. Any thoughts?
     
  10. Patrick Sun

    Patrick Sun Moderator
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    Tony,
    Go to this link to get the correction values for your RS SPL meter for the low end response.
    I'll reprint the list here:
    10Hz add 20
    12.5Hz add 16.5
    16Hz add 11.5
    20Hz add 7.5
    25Hz add 5
    31.5Hz add 3
    40Hz add 2.5
    50Hz add 1.5
    63Hz add 1.5
    80Hz add 1.5
    100Hz add 2
    125Hz add .5
    160Hz add -.5
    200Hz add -.5
    250Hz add +.5
    315Hz add -.5
    400Hz add 0
    500Hz add -.5
    630Hz add 0
    800Hz add 0
    1kHz add 0
    1.25kHz add 0
    1.6kHz add -.5
    2kHz add -1.5
    2.5kHz add -1.5
    3.15kHz add -1.5
    4kHz add -2
    5kHz add -2
    6.3kHz add -2
    8kHz add -2
    10kHz add -1
    12.5kHz add +.5
    16kHz add 0
    20kHz add +1
    ------------------
    PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; LDs
     
  11. Tony Genovese

    Tony Genovese Supporting Actor

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    My understanding re the Radio Shack is that they vary all over the lot and that a single correction value is not possible. Different examples will measure differently. Also, the correction values you listed have been said to apply to the analog meter and not the digital. Since I checked the RS against a totally different meter (non RS) and they both measured the same, do I need to correct the Infinity meter, too?
    Or perhaps my digital RS meter is more accurate?
    I am confused.
     
  12. Patrick Sun

    Patrick Sun Moderator
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    The RS Analog and Digital SPL meters need the same correction values. The caveat is that anything above 12KHz, the RS SPL meter is useless.
    ------------------
    PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; LDs
     
  13. Tony Genovese

    Tony Genovese Supporting Actor

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    Is the correction value a function of the microphone used or filtering or some Fletcher-Munson (sp?) issue?
    The reason I ask is that it seems strange that the Infinity meter has the exact same response as the RS meter. Maybe it's an RS meter in disguise?
     
  14. Patrick Sun

    Patrick Sun Moderator
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  15. Michael Robbins

    Michael Robbins Auditioning

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    Tom,
    Right, I omitted that part. Some other considerations, if they really are considerations, are wall wart vs. onboard power suppy. (I guess that's how you would say it?) Rane has wall wart power supply while Ashly, Symetrix, and Behringer have "real" power supplies.
    What's the best street price for the Symetrix? And which parametric unit are you still considering for the SS series subwoofers, the PE17?
     
  16. Richard Greene

    Richard Greene Stunt Coordinator

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    If you can't find a used equalizer, the Alesis 320
    is a stereo 30 band (fixed) equalizer that cost me
    $219 for at Mars Music. Its 40Hz. 1/3 octave control
    will work well on your problem. I do not recommend
    this equalizer for satellite speakers - it does not produce high-end sound quality -- but it is fine for a subwoofer and much easier to set than a parametric equalizer (of course, also not as flexible).
    The Rat Shack meter is useless for treble -- I would
    recommend ignoring readings for 2,000Hz. and higher.
    For bass, you should at least adjust the
    the C-weighting to flat:
    add 6dB at 20Hz.
    add 3dB at 30Hz.
    add 1db at 50Hz.
    The Rat Shack owner's manual gives a frequency response
    of +/- 3dB from 20Hz. (I think) to 10,000Hz.
    Hopefully the largest deviations from flat are at the frequency extremes.
     
  17. Tony Genovese

    Tony Genovese Supporting Actor

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    I've seen the Symetrix as low as $329. The PE-17 is also available at that price. These were from: http://www.unclebobsmusic.com/
    The problem with these eq's is that nobody seems to have any of them in stock. There seems to be a long backorder for the Behringers from everybody. Great price, but as someone stated, not too good if you can't get one.
    I did not call Uncle Bob's to find out if they had any in stock, though I checked Full Compass, Markertek and Sweetwater. None of them had either the Ashly, Behringer, or Symetrix. Markertek had 1 PE-17 for $399 and in stock. Sweetwater had 1 551E in stock for $358. I have had excellent dealings with them, so I ordered it. (Now they're out of stock : ( They ship Fedex, are very prompt, and have excellent customer service. I ordered a K1 from them last Tuesday and had it delivered via Fedex on Thursday. Not rock bottom prices but they seem to stock stuff and ship fast and secure.
    BTW, Full Compass quoted me a price of $115.02 for the PEQ-2200. Again, though, no idea when it would be available. I was told "it could be months".
     
  18. Tony Genovese

    Tony Genovese Supporting Actor

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    Thanks, Wayne. Evidently the Symetrix has a shelving eq too for lows and highs that's variable, so it sounds as if it performs similarly to the Rane.
    Is the so called house curve you talk about why everyone is saying to boost 20hz by 7 db compared to the RS sound pressure meter? I just don't understand this correction thing, particulary since I have checked it against another, different meter and it measures the same. Dick Pierce is fond to point out that he's measured the response of umpteen RS meters and they all measure differently. How then can a universal correction curve work properly?
    Sorry if I am unclear but I do find the whole topic confusing.
     
  19. Tony Genovese

    Tony Genovese Supporting Actor

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    Thanks, Wayne. I got it! I am expecting my Symetrix on Thursday, and should have some fun equalizing my system.
     
  20. Tom Vodhanel

    Tom Vodhanel Cinematographer

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    >>What's the best street price for the Symetrix?> And which parametric unit are you still considering for the SS series subwoofers, the PE17?
     

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