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Subwoofer calibration for music

Discussion in 'Archived Threads 2001-2004' started by Mal P, Jan 27, 2002.

  1. Mal P

    Mal P Stunt Coordinator

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    Howdy,

    I recently purchased a HSU Vtf-2 subwoofer and so far it's been very good. I enjoy the extra "slam" for films over my main speakers (which extend down to 30hz, -3dB or so) and it's *almost* as fast as my mains for music (just a tad laggy, but the extra depth below 30hz makes up for it).

    I've calibrated it for films using Video Essentials and the Radioshack SPL meter. All speakers set to 75dB, and the sub also to 75dB. It seems I have a good room (I have no back wall to speak of... it goes extends back about 30m or so - the width is 5m only though) and so the needle doesn't flicker all that much, only a 2dB or so variation between various positions on my couch. I have my volume on the sub at around the 12'oclock position, and I have my sub level set to 0dB on my Sony DA555ES receiver (it can go +/- 10dB). All this is great for movies, in Die Hard DTS, every machine gun shot I feel on my chest. It's fantastic.

    However, what about for music? I tried keeping it at the same setting for music, and yikes, way too much bass, completely overpowered the mids and highs. -8dB or so is good for music. Is there any proper way of calibrating it exactly for music though?

    What about concert DVDs? What level should I set my sub when listening to the LFE on Dolby Digital tracks, and DTS tracks?

    Sincerely,

    Mal
     
  2. Jon D

    Jon D Stunt Coordinator

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    Funny, I always find that my movie calibrations result in low levels of bass for music. I have to turn my sub output up.

    I wouldn't think concert DVD's (in Dolby or DTS) should be played any differently than a movie. The discs were hopefully mastered using the same channel volume setup as a movie soundtrack
     
  3. ling_w

    ling_w Second Unit

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    Here is what I posted in another thread:

    I generally don't like the idea of calibrating based on pink noise since too many inaccurate, with factors that will lead to errors including:

    1. Ratshack's meter rolloff at low freq that is uncorrectable with wide band noise signal.

    2. Room peaks and/or nulls that skews the whole reading

    3. Rolloff of the sub which affects the whole reading.

    It would not be a problem if you have your mains set as large and are using your sub only for LFE (since how loud is a LFE rumble compared to the rest of the channel is relative,) but if you set your mains to small and let the sub handle the all the bass, you will get an unatural transition between the mains and sub in the crossover region, resulting not just in too much boom, but any instrument that transition across the crossover region will have notes jump out toward you.

    As to explaination to above reasons:

    In 1, you could compensate for the ratshack's SPL meter's error if you are measuring spot freq, but if you are doing wide band noise, you would have to do some avg SPL decrease for the bandwidth you are measuring.

    In 2, room peaks of 10-15dB is not uncommon, especially with corner placement. A few of those peaks are enough to throw the reading off enough, even if the peak spans a very narrow range in freq.

    In 3, the reading has tom compensate for the lack of output below the sub's rolloff freq. If your sub has a rapid rolloff below 40hz, then you are in effect measuring the accoustic energy across 1 octave (40-80hz) as opposed to 2 (20-80hz) Your setting automatically becomes 3dB too high.

    Now combine the above 3 problems together, and you not knowing the f3 of the sub and how much to compensate the SPL meter based on the f3, not including the room peak's intensity, you end up with too many unknowns to get an accurate adjustment.

    The ideal way is to measure the f3 of the mains and f6 of the sub (assuming they are 12dB/24dB rolloff) (this is assumed to be at the crossover freq) and try to set the mains 3dB higher than the sub. You would probably have to measure seperately 1 oct above and below the crossover freq just to make sure your f3 and f6 did not reside on or near a room mode where it would affect the reading, and then measure the summed output to ensure a smooth transistion.
     
  4. Steve WC

    Steve WC Stunt Coordinator

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    Copy of letter from owner of HSU on tuning that sub.

    Hello, I thought I would share this info as it may help some

    others.The Question was specific about tuning with my Yamaha

    RX-V1000 but there is info for others in his responce also.

    This is customer service!!

    Question

    I am trying to set up my Subwoofer with my Radio Shack SPL

    Meter.

    My Yamaha RXV-1000 receiver gives me choices of frequencies to

    use to set it up Which do you recommend I use with the meter

    to set my subwoofer?

    Here are my Frequency choices. 35Hz, 39Hz, 44Hz, 50Hz, 56Hz,

    63Hz, 70Hz, 79Hz, 88Hz, 99Hz, 111Hz, 125Hz, 140Hz,

    157Hz,177Hz, 198Hz, 223Hz, 250Hz or WIDE.

    I expect you will want me to use either Wide or one of the

    lower choices here but not sure which? There was no choice for

    the main & Surround speaker tone only LFE.

    My speakers are set to 75db & I plan on setting the Subwoofer

    to 85db.

    I listen to Movies as well as music on my HT system. I am at

    best a beginner & still learning. Tuning for me has been a

    difficult experience. I started with my crossover set to 8

    O’clock as you recommended. I have it now at the 9:30 position

    & my volume at the 10 O’clock position.& Set for max

    extension. So far this seems to be the best place for all

    around listening.

    Responce#1 from Po Hsu:

    Are those test frequencies or crossover frequencies? Sounds

    more like crossover frequencies. Can you FAX over the pages

    that describes it? FAX to (714)666-9261.

    You should not be setting the subwoofer 10 dB louder than the

    main speakers. I would go for at most 3 dB louder. If the

    levels can be set differently for each source, I would go for

    3 dB higher for video sources compared to audio sources. I set

    mine for flat response for music (75 dB for mains and sub),

    and 3 dB hotter for the sub for HT.

    Responce#2 from Po Hsu:

    Got your FAX. I stand corrected. Its interesting that they

    included a narrow bandwidth pink noise for testing the in-room

    response. That is great. What you need to do is

    1. Set the mains, center and surround to small and yes to

    subwoofer.

    2. Set the crossover switch on the VTF-2 to out.

    3. Play the test tones from 35 Hz up to 88 Hz and see what

    readings you get for each frequency. If the measurements are

    fairly even, skip to step 5.

    4. If the upper frequencies are too high, set the VTF-2

    crossover to in and adjust the frequency control to get the

    flattest response from 35 to 88 Hz.

    5. Set the test frequency to wide. Adjust level of subwoofer

    to get about 3 dB higher reading on the SPL meter than the

    main speakers.

    6. Switch to a stereo source (CD, for example). If you can set

    the subwoofer level separately for each source, set the

    subwoofer level 3 dB less than what you have set for the home

    theater sources.

    Too bad that Yamaha still refuse to give the user the

    flexibility to select different crossover frequencies. You

    stand a much better chance of getting a flatter response and

    make better use of your speakers if they allow you to choose

    the crossover frequency as well as the test tones. With your

    large main speakers, I would have crossed over at 50 Hz or so.

    An alternative is

    1. Set the mains to large, and select to send all bass to both

    the mains and the sub. Set the subwoofer level on the Yamaha

    to -3 dB.

    2. Set the crossover switch on the VTF-2 to in.

    3. Play the test tones from 35 Hz up to 88 Hz and see what

    readings you get for each frequency.

    4. Adjust the frequency control and level control of the VTF-2

    to get the flattest response from 35 to 88 Hz.

    5. Set the subwoofer level to 0 dB for video sources, and - 3

    dB for audio sources..
     
  5. Mal P

    Mal P Stunt Coordinator

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    Thanks for all the great advice, especially to Steve for copying the E-mail from Poh Hsu!
    I think I've got it well set now... 0dB on my receiver for movies, and the 1 o'clock position on the sub volume dial.
    For music concert DVDs (that contain an LFE track) I have it set to -5dB. This sounds very good, with enough "oomph" to give that live feeling.
    For music CDs, I also have it set to -5dB or so. While this may be a little "hot" for music, since I listen to CDs at moderate volume levels, it fills in the bass very nicely. I also enjoy the extra kick down low, just to make some songs a bit more exciting. What I had before, -8dB, was far too low, it sounded exactly like my normal speakers. That's not what I want from a good subwoofer [​IMG]
    I could tell the immediate difference in Filter's "Hey Man Nice Shot". The song, which has fantastic bass beats, just sounded fantastic, I felt like I wanted to bang my head all the way through it.
    I'm not after dead accuracy with my setup though... it's been calibrated using well known, common methodologies, and I'm quite pleased with the sound. Maybe once I move onto higher end gear, with a dedicated HT room, I'll get it done to absolute accuracy.
    Thanks everyone, most beneifical!
    Cheers,
    Mal
     

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