Bass Ports/Equalization; Speaker Mounting - Tannoy Proto-J Reference Manual

3.4 Speaker Mounting

You've probably got your monitors delicately balanced on your console meter bridge, or sitting on a
counter top beside your hard disc editor. Find some music with some real solid low end that you
know well. Try listening to this music with the speaker sitting directly on the mounting surface and
then with it sitting on a thin piece of rubber pad. Hear a difference? Which one sounds more like the
recording should? Does one get tubby, or muddy? Depending on the type of mounting surface, you
may find it beneficial to use a thin layer of flexible material (i.e. Bluetack) beneath the enclosure.
This not only absorbs some vibration, but will help prevent the monitor from vibrating off of its
mounting surface.
3.5 Bass Ports
The Reveal monitors' bass port is located on the back panel. You should keep the back panels at
least 6" (150 mm) away from the nearest wall surface to avoid an overblown bass sound. If you can-
not avoid being close to the wall or if you're using a separate subwoofer, you may want to consider
plugging the port tubes on your near-fields with a closed cell foam-rubber plug, friction fit for a full
seal. Because the ports aren't needed if the monitor speakers are being used with a high pass filter,
you won't be losing any bass performance and you can improve the mid-bass response by plugging
the ports.
3.6 Equalization
Our feeling is that you shouldn't equalize monitors at all; variations in the monitor
response should be fixed through placement (after all, that's what this manual's about). But we real-
ize that equalization is sometimes a necessary evil. If you have a choice of equalizers for monitor
applications, less is more. The fewer the number of filters, the better the equalizer will sound. A
stereo five band parametric is better than a stereo 15 band that is better than a stereo 1/3 Octave.
You may not realise that in all but one or two brands of 1/3 Octave equalizers, all 30 filters are in
series. There is a minimum transit time through each filter of some 25 microseconds, plus just a bit
of decay time for each filter. Even with the equalizer set flat, it does not behave like a straight piece
of wire in the time domain. If you don't need to equalize your monitors, then don't hook an equalizer
up to them at all.
An important thing to keep in mind if you are equalizing these compact monitors is that they are not
intended to substitute for really large loudspeaker systems you might use for tracking synth lines, or
drum samples. Don't try to equalize them to sound the same as the 15" monitors you were listening
to in the in the music store. The equalization of your nearfields should be undertaken with great sub-
tlety. With only the best intentions of correcting some of the placement related characteristics we've
talked about here, a subtle bit of reduction in the mid bass where the console or table top will give
you a rise, perhaps a bit of tailoring to taste here or there. As a general rule for this application, you
should never need more than 6 dB of control range, and you should never see two adjacent filters
with more than 6 dB of difference between them. Over equalization can reduce system headroom,
and introduce phase distortion resulting in greater problems than cures.