Eqing Monitors?

Archived from groups: rec.audio.pro (More info?)

Hallo!

What do you think about equing studio monitors to extend the linearity
in the low end? We are talking about JBL LSR32. Their frequency
response starts to decrease below 80Hz.

For testing I inserted a 31Band digital Behringer EQ from my
live-emergency(!)-rack and I boosted the 50Hz ca. 5dB 30Hz 10dB.

Since I have no regular measuring equipment, I used a C451 and Wavelab
Analyser and pink noise to "measure" the linearity.
Sounds good to me.

1. What do you think about EQing the low end?
2. What EQ would you suggest? (if yes)
3. How to meassure the frequency response with normal studio equipment?

Greetings Thomas
16 answers Last reply
More about eqing monitors
  1. Archived from groups: rec.audio.pro (More info?)

    Thomas Thiele wrote:

    > What do you think about equing studio monitors to extend the linearity
    > in the low end? We are talking about JBL LSR32. Their frequency
    > response starts to decrease below 80Hz.

    It does? What are you putting through it? I suspect that the problem
    isn't with the speakers as much as it is your room. If you have the
    opposite problem, a build-up of bass due to the speaker being too close
    to a wall or corner, you can successfully compensate for that by
    cutting the low end with an equalizer. But if your problem is that you
    want to hear more bass, adding it with EQ might work in one position,
    but it will be different in another listening position. Also, you'll be
    pumping more power into the speaker at low frequencies and you power
    amp or speaker may not be able to take it at the volume you want to
    listen. People who want a lot of low end usually want a LOT of low end.

    > Sounds good to me.

    Did you walk around the room listening to music when you had that boost
    set?

    you suggest? (if yes)

    > 3. How to meassure the frequency response with normal studio equipment?

    You can't, unless you consider listening to be measurement and ears to
    be normal studio equipment. Cheap and simple spectrum analyzers are
    uselessly inadequate for making room measurements at low frequencies.
  2. Archived from groups: rec.audio.pro (More info?)

    Hallo Mike and all others!

    Look at http://www.jblpro.com/pub/manuals/lsrman.pdf. You'll see on
    page 7 of the manual that the response curve drops off at around 80Hz.
    At 50Hz -5dB and at 30Hz -12dB.
    My intention was not to fix room problems. Perhabs there are some
    little, but not that much. I never measured it, but I think I know how
    they would sound.
    Btw. a little picture:
    http://www.krachwerk.de/ASGStudioreport/studiolinks.jpg
    (the stands are some of those temporary solutions that remains
    longer...)

    I'm just wondering if you can/should extend the linearity in the low
    end to say 50Hz by using EQ.
    Some ascii-graphic:
    ___________________
    / /
    / /
    / /

    ^with EQ
    ^without EQ
  3. Archived from groups: rec.audio.pro (More info?)

    Thomas Thiele <jana.luetz@gmx.de> wrote:
    >
    >What do you think about equing studio monitors to extend the linearity
    >in the low end? We are talking about JBL LSR32. Their frequency
    >response starts to decrease below 80Hz.
    >
    >For testing I inserted a 31Band digital Behringer EQ from my
    >live-emergency(!)-rack and I boosted the 50Hz ca. 5dB 30Hz 10dB.
    >
    >Since I have no regular measuring equipment, I used a C451 and Wavelab
    >Analyser and pink noise to "measure" the linearity.
    >Sounds good to me.
    >
    >1. What do you think about EQing the low end?

    I think it really doesn't fix the problem. If the issue is the monitor
    and not the room, you can use EQ to extend the low frequency corner, BUT
    if you do this, you get very little headroom at low frequencies. The
    speaker goes into clipping (full driver excursion) very easily.

    >2. What EQ would you suggest? (if yes)

    If you absolutely HAVE to do this, I'd suggest doing it with lumped
    sum filters added to the crossover of the speaker.

    >3. How to meassure the frequency response with normal studio equipment?

    The easiest thing to do is to get a $20 SPL meter. Radio Shack sells a
    usable cheap one in the US. Now, you can play tones through the speaker
    from a signal generator or test disc and get an SPL level in the room.

    If you do this, first of all you need to know that the low frequency
    response of the meter drops off, so you need to get the C-weighted curve
    off the net somewhere, and subtract the curve you draw of the low end
    from the response curve of the meter to get the actual response.

    Secondly you need to know that, because of room effects, everything will
    change when you move a couple feet.

    My suggestion is that if you change the room so that the room response
    is rising at about the same point where the speaker response is dropping
    off, you'll get better results for less money.
    --scott
    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."
  4. Archived from groups: rec.audio.pro (More info?)

    Thomas,

    > What do you think about equing studio monitors <

    You got the right answer (don't do it), and I'll add a little.

    > For testing I inserted a 31Band digital Behringer EQ <

    The peaks and nulls that occur at low frequencies in small rooms are far
    narrower than 1/3 octave. So even if EQ was useful, which it's not, you'd
    need to use a parametric EQ and adjust it very carefully.

    > Since I have no regular measuring equipment, I used a C451 and Wavelab
    Analyser and pink noise to "measure" the linearity. <

    The C-451 can be used, but only if you have an omni capsule. I have a 451
    with a CK22 capsule and it works very well for room analysis. But you also
    need a source of tones in very fine increments, like 1 Hz. Or better, use
    software like ETF here:

    www.acoustisoft.com

    --Ethan
  5. Archived from groups: rec.audio.pro (More info?)

    Thomas Thiele wrote:

    > Look at http://www.jblpro.com/pub/manuals/lsrman.pdf. You'll see on
    > page 7 of the manual that the response curve drops off at around 80Hz.
    > At 50Hz -5dB and at 30Hz -12dB.

    That's not too bad for a small monitor, actually.

    > I'm just wondering if you can/should extend the linearity in the low
    > end to say 50Hz by using EQ.

    As Scott, and I think I pointed out, in theory you could do that, but
    in practice it might not work out so well. You'd be putting more power
    into the speaker at low frequencies which not only takes away power
    from the more audible portion of the spectrum (assuming you don't
    upgrade to a higher power amplifier, if you have the unpowered version)
    but you could damage the speaker by putting too much current into the
    voice coil in order to move enough air at low frequencies to keep you
    happy.

    But like anything else in this business, it doesn't hurt to try, as
    long as you understand what the problems might be and be on the lookout
    (or listen-out) for them. When you hear farts instead of nice round
    bass, back it off.

    Have you considered a subwoofer? That's probably the best solution, and
    80 Hz is a good frequency for a sub to start working.
  6. Archived from groups: rec.audio.pro (More info?)

    Thomas Thiele wrote:

    > I'm just wondering if you can/should extend the linearity in the low
    > end to say 50Hz by using EQ.

    Yes, but you may well go beyond the ability of the power
    amplifier to deliver signal at the boosted LF.


    Bob
    --

    "Things should be described as simply as possible, but no
    simpler."

    A. Einstein
  7. Archived from groups: rec.audio.pro (More info?)

    Thomas Thiele <jana.luetz@gmx.de> wrote:
    >
    >Look at http://www.jblpro.com/pub/manuals/lsrman.pdf. You'll see on
    >page 7 of the manual that the response curve drops off at around 80Hz.
    >At 50Hz -5dB and at 30Hz -12dB.

    That's in an anechoic chamber. When you put it in the room, it will
    be different because there will be a resonant space between the wall
    and the speakers. If you pull the speakers farther into the room,
    the resonance gets wider and lower frequency, if you put them in closer
    toward the wall it gets narrower and higher. You move the speakers
    around until the response is flat, using the room to emphasize the low
    end where the speakers drop off.

    >My intention was not to fix room problems. Perhabs there are some
    >little, but not that much. I never measured it, but I think I know how
    >they would sound.

    If you had speakers that measured flat in an anechoic chamber, they
    would sound very boomy in the room.

    If you have never measured the room, do so before thinking about
    anything else.
    --scott


    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."
  8. Archived from groups: rec.audio.pro (More info?)

    "Thomas Thiele" <jana.luetz@gmx.de> wrote in message
    news:1125398930.625705.9730@g43g2000cwa.googlegroups.com
    > Hallo!
    >
    > What do you think about equing studio monitors to extend
    > the linearity in the low end? We are talking about JBL
    > LSR32. Their frequency response starts to decrease below
    > 80Hz.
    >
    > For testing I inserted a 31Band digital Behringer EQ from
    > my live-emergency(!)-rack and I boosted the 50Hz ca. 5dB
    > 30Hz 10dB.
    >
    > Since I have no regular measuring equipment, I used a
    > C451 and Wavelab Analyser and pink noise to "measure" the
    > linearity.
    > Sounds good to me.
    >
    > 1. What do you think about EQing the low end?

    Eqing monitors is like tasting wine with a sugar cube in
    your mouth.
  9. Archived from groups: rec.audio.pro (More info?)

    "Arny Krueger" <arnyk@hotpop.com> wrote in message
    news:UpydnV29ovROJoneRVn-3g@comcast.com...
    > "Thomas Thiele" <jana.luetz@gmx.de> wrote in message
    > news:1125398930.625705.9730@g43g2000cwa.googlegroups.com
    >> Hallo!
    >>
    >> What do you think about equing studio monitors to extend
    >> the linearity in the low end? We are talking about JBL
    >> LSR32. Their frequency response starts to decrease below
    >> 80Hz.
    >>
    >> For testing I inserted a 31Band digital Behringer EQ from
    >> my live-emergency(!)-rack and I boosted the 50Hz ca. 5dB
    >> 30Hz 10dB.
    >>
    >> Since I have no regular measuring equipment, I used a
    >> C451 and Wavelab Analyser and pink noise to "measure" the
    >> linearity.
    >> Sounds good to me.
    >>
    >> 1. What do you think about EQing the low end?
    >
    > Eqing monitors is like tasting wine with a sugar cube in your mouth.

    THAT'S what I've been doing wrong! Damn.

    Steve King
  10. Archived from groups: rec.audio.pro (More info?)

    > What do you think about equing studio monitors to extend the linearity
    > in the low end? We are talking about JBL LSR32. Their frequency
    > response starts to decrease below 80Hz.

    I think it's a bad idea.

    > For testing I inserted a 31Band digital Behringer EQ from my
    > live-emergency(!)-rack and I boosted the 50Hz ca. 5dB 30Hz 10dB.
    >
    > Since I have no regular measuring equipment, I used a C451 and Wavelab
    > Analyser and pink noise to "measure" the linearity.
    > Sounds good to me.

    The 451 is definitely not a measurement mic.
    AND so far we know nothing abou the room the speakers are in.

    > 1. What do you think about EQing the low end?

    Bad idea usually. Playing with placement and ports etc. is OK but EQ is
    usually not a good idea.

    > 2. What EQ would you suggest? (if yes)
    > 3. How to meassure the frequency response with normal studio equipment?

    What is "normal studio equipment"?

    JP
  11. Archived from groups: rec.audio.pro (More info?)

    Arny Krueger wrote:

    > Eqing monitors is like tasting wine with a sugar cube in
    > your mouth.

    If the on-axis anechoic response is not flat, why, other
    than driving and coil dissipation considerations, shouldn't
    they be equalized? Oh, you mean with something like a
    graphic equalizer I'll bet. In that case I agree. With the
    more sophisticated inverse convolution filtering approach it
    can only improve matters.

    Then, at least its flat and time accurate before the room
    does its dirty and for near field monitoring that dirty
    isn't as much as for a leisure listening setup.


    Bob
    --

    "Things should be described as simply as possible, but no
    simpler."

    A. Einstein
  12. Archived from groups: rec.audio.pro (More info?)

    Thomas Thiele wrote:

    > I'm just wondering if you can/should extend the linearity in the low
    > end to say 50Hz by using EQ.

    No you shouldn't because outside the speaker's desgined bandwidth
    performance may (probably) not be linear. You want bottom you need a
    sub.

    --
    ha
  13. Archived from groups: rec.audio.pro (More info?)

    "Bob Cain" <arcane@arcanemethods.com> wrote in message
    news:df3fgh0kih@enews1.newsguy.com

    > Arny Krueger wrote:

    >> Eqing monitors is like tasting wine with a sugar cube in
    >> your mouth.

    > If the on-axis anechoic response is not flat, why, other
    > than driving and coil dissipation considerations,
    > shouldn't they be equalized?

    The whole problem with equalizing is about trying to figure
    out what sort of response we want to have. AFAIK, there is
    no generally agreed-upon answer.

    The FR of a speaker isn't a curve, its a large family of
    curves, each representing the speaker's response in a
    different direction. The ear hears an weighted integration
    of these curves.

    I doubt that many speakers are designed to have flat
    response in an anechoic chamber, at least not without
    references to a number of other kinds of frequency response
    tests.

    > Oh, you mean with something like a graphic equalizer I'll
    > bet.

    No, I'm thinking about the best equalizer that we could
    think of.

    >In that case I agree.
    > With the more sophisticated inverse convolution filtering
    > approach it can only improve matters.

    That would be more like the best equalizer that we could
    think of. However, we have no electrical means for
    equalizing the response of a speaker in different directions
    at the same time.

    > Then, at least its flat and time accurate before the room
    > does its dirty and for near field monitoring that dirty
    > isn't as much as for a leisure listening setup.

    Mt attitude is that a speaker is a box that does something
    that we need it to do. In monitoring it needs to have broad
    and smooth response so that you can hear all the different
    audible parts of the music. Every speaker that has broad and
    smooth response has response that differs from other
    speakers in the details. Once you learn what those details
    are, the most important thing is that the speaker's response
    be stable.

    I'll admit it - I've tried to integrate a subwoofer with my
    monitors. In the end, they have been mostly used without the
    subwoofer. There's two practical problems with setting up a
    subwoofer - one is getting balanced with the mains and the
    other is keeping it that way. That became a hassle and I
    just wanted to make music.
  14. Archived from groups: rec.audio.pro (More info?)

    Bob Cain <arcane@arcanemethods.com> wrote:
    >Arny Krueger wrote:
    >
    >> Eqing monitors is like tasting wine with a sugar cube in
    >> your mouth.
    >
    >If the on-axis anechoic response is not flat, why, other
    >than driving and coil dissipation considerations, shouldn't
    >they be equalized? Oh, you mean with something like a
    >graphic equalizer I'll bet. In that case I agree. With the
    >more sophisticated inverse convolution filtering approach it
    >can only improve matters.

    If on-axis anechoic response is not flat on the low end, placement
    will often compensate for this.

    If on-axis anechoic response is not flat in the midrange, the monitors
    should be discarded and replaced.

    Occasionally equalization might help things a a little, but usually if
    this is the case the manufacturers have already designed it into the
    crossover.
    --scott


    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."
  15. Archived from groups: rec.audio.pro (More info?)

    Arny Krueger wrote:
    > "Bob Cain" <arcane@arcanemethods.com> wrote in message
    > news:df3fgh0kih@enews1.newsguy.com
    >
    >
    >>Arny Krueger wrote:
    >
    >
    >>>Eqing monitors is like tasting wine with a sugar cube in
    >>>your mouth.
    >
    >
    >>If the on-axis anechoic response is not flat, why, other
    >>than driving and coil dissipation considerations,
    >>shouldn't they be equalized?
    >
    >
    > The whole problem with equalizing is about trying to figure
    > out what sort of response we want to have. AFAIK, there is
    > no generally agreed-upon answer.

    Why would anything other than flat be desirable for a mixing
    monitor?

    > The FR of a speaker isn't a curve, its a large family of
    > curves, each representing the speaker's response in a
    > different direction. The ear hears an weighted integration
    > of these curves.

    True, but for a nearfield monitoring situation the direct
    sound from on-axis should much predominate. Enough so, I
    would think, that using filters derived from inverting a
    pair of in-situ measurements taken at the apex of the usual
    nearfield triangle should work very well.


    Bob
    --

    "Things should be described as simply as possible, but no
    simpler."

    A. Einstein
  16. Archived from groups: rec.audio.pro (More info?)

    On Wed, 31 Aug 2005 14:49:51 -0700, Bob Cain
    <arcane@arcanemethods.com> wrote:

    >Why would anything other than flat be desirable for a mixing
    >monitor?

    I think the term "flat" might be the real sticking point.
    IOW, flat for first arrival sound or flat for summed
    room response? Or some compromise? Flat for one listener
    or flat for an averaged space for x listeners. like that.

    A couple years ago, I built a prototype crossover and
    bass equalizer for some speakers with essentially *no*
    mechanical limitations. Four cylinders with twin 18"
    cost-no-object woofers each, intended for the passband
    to be below resonance.

    The EQ (based on Linkwitz's early Speaker Builder article,
    *essential reading* to anyone interested in the topic,
    was taste-tested with absolutely no blinding, and yet...

    I and several kindred spirits had fairly strong
    preferences for a final system Q of 0.5 and F-sub-c
    of about 8Hz.

    FWIW, maybe not much,

    Chris Hornbeck
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