Setting up a sub in a monitoring environment

[lanstrad]

I just added a M-Audio active subwoofer (SBX10) in my studio, that
connects from a Yamaha 02R board, then to a Alesis RA100 (100 watts)
reference amp (to Yamaha NS10M monitors).

Working with a sub bin is new for me, and I was wondering if some of
you might have experience and or suggestions on best (starting) ways
to setup with this.

The beast is said to be 240 watts. More specifically, which crossover
settings should be set ? (goes from 50 Hz to 200 Hz - splitting signal
from the 02R by routing everything below that frequency to the sub and
everything above to the mains (NS10Ms through their connected amp).

Then, the volume knob goes from -30dB to +6dB. Should it be set only
by ear, or is there a logic behind it, such as nominal output of the
02R or something else ?

Last but not least, I read 3 location theories for placing the sub...
As a home studio and less than ideal furniture placement, all 3 are
challenging... (middle and same distance, corner - there are
obstacles..., then the more sophisticated: place it in your monitoring
chair, crawl around the room and where it sounds better, place it
there.... Gee, and id it falls in the middle of the room ????......)
I understand that there's no magic and each room is unique, but I'd
like to read what you guys have done with the placement issue...

Thanks,
Rob

[Scott Dorsey]

lanstrad > wrote:
>I just added a M-Audio active subwoofer (SBX10) in my studio, that
>connects from a Yamaha 02R board, then to a Alesis RA100 (100 watts)
>reference amp (to Yamaha NS10M monitors).
>
>Working with a sub bin is new for me, and I was wondering if some of
>you might have experience and or suggestions on best (starting) ways
>to setup with this.

Really this isn't a good configuration. Adding a sub kills a lot of
what people _do_ like about the NS10M, and it isn't going to give you
what you think it will.

>The beast is said to be 240 watts. More specifically, which crossover
>settings should be set ? (goes from 50 Hz to 200 Hz - splitting signal
>from the 02R by routing everything below that frequency to the sub and
>everything above to the mains (NS10Ms through their connected amp).

Play a swept bass tone. Listen. Adjust the crossover point for the
least audible distortion across the band.

If you can hear the sound move around the room from the sub to the
mains as it sweeps, the crossover is set too high.

>Then, the volume knob goes from -30dB to +6dB. Should it be set only
>by ear, or is there a logic behind it, such as nominal output of the
>02R or something else ?

Play the sweep tone. Move the sub around and adjust the level until
the sweep tone is even at the listening position and it stays even
as it goes through the crossover region.

>Last but not least, I read 3 location theories for placing the sub...
>As a home studio and less than ideal furniture placement, all 3 are
>challenging... (middle and same distance, corner - there are
>obstacles..., then the more sophisticated: place it in your monitoring
>chair, crawl around the room and where it sounds better, place it
>there.... Gee, and id it falls in the middle of the room ????......)
>I understand that there's no magic and each room is unique, but I'd
>like to read what you guys have done with the placement issue...

Use your ears and listen to the swept sine tone. The trick with the
reciprocity principle works, but is not always easy to do.

I do have to say that your monitoring system strikes me as a really
difficult combination to work with.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Robert Morein]

"lanstrad" > wrote in message
...
> I just added a M-Audio active subwoofer (SBX10) in my studio, that
> connects from a Yamaha 02R board, then to a Alesis RA100 (100 watts)
> reference amp (to Yamaha NS10M monitors).
>
> Working with a sub bin is new for me, and I was wondering if some of
> you might have experience and or suggestions on best (starting) ways
> to setup with this.
>
> The beast is said to be 240 watts. More specifically, which crossover
> settings should be set ? (goes from 50 Hz to 200 Hz - splitting signal
> from the 02R by routing everything below that frequency to the sub and
> everything above to the mains (NS10Ms through their connected amp).
>
If you don't want to go to a lot of work, and you want to avoid most of the
hazards Scott refers to, set the frequency to 50 Hz. You'll do the least
damage that way.

> Then, the volume knob goes from -30dB to +6dB. Should it be set only
> by ear, or is there a logic behind it, such as nominal output of the
> 02R or something else ?
>
The normal procedure is to use an SPL meter, perhaps even the accursed Radio
Shack SPL meter, with a tone generator. Adjust for flattest response.

> Last but not least, I read 3 location theories for placing the sub...
> As a home studio and less than ideal furniture placement, all 3 are
> challenging... (middle and same distance, corner - there are
> obstacles...,

I favor corner placement. This permits running the sub at lower power to
obtain the same reinforcement. Although I have obtained good results, there
are big arguments here. I would not place it equidistant between corners.
Choose an unsymmetrical distance.

> then the more sophisticated: place it in your monitoring
> chair, crawl around the room and where it sounds better, place it
> there.... Gee, and id it falls in the middle of the room ????......)

That is unlikely to happen.
> I understand that there's no magic and each room is unique, but I'd
> like to read what you guys have done with the placement issue...
>
> Thanks,
> Rob

Rob, one problem not mentioned so far is coloration caused by the materials
used to construct the room. If your room is made of drywall, a sub can
excite the drywall to produce a sound that is NFG. I have found that corner
placement with a very low sub crossover frequency can mitigate this, as the
drywall is better braced at the corner. The sound of a sub is not all its
own. Permit me to describe a recent example. I have a system I use for
software development, but I wanted some music. I had an Altec-Lansing
3-piece computer speaker setup that was known to have mushy bass that
localized to under the table -- in a word, everything bad about computer
speakers. I relocated this system in the basement, with the "subwoofer"
located DIRECTLY on the concrete floor. The result: clean, taught bass that
cannot be localized.

Personally, in line with Scott's opinion, I would not mix with a sub, unless
it has been very carefully set up and proven to be flat. Note that flatness
must be measured at the listening position. In my mixing room, I have a zone
of bass enhancement that caused me to mix thin, until I realized what it
was.

Bob Morein
(310) 237-6511

[Arny Krueger]

"lanstrad" > wrote in message


> I just added a M-Audio active subwoofer (SBX10) in my
> studio, that connects from a Yamaha 02R board, then to a
> Alesis RA100 (100 watts) reference amp (to Yamaha NS10M
> monitors).

> Working with a sub bin is new for me, and I was wondering
> if some of you might have experience and or suggestions
> on best (starting) ways to setup with this.

> The beast is said to be 240 watts. More specifically,
> which crossover settings should be set ? (goes from 50 Hz
> to 200 Hz - splitting signal from the 02R by routing
> everything below that frequency to the sub and everything
> above to the mains (NS10Ms through their connected amp).

A nice little sub - 10" driver.

Your best bet - use the internal crossover, and daisy chain the RA100 that
drives the NS10M from its output.

> Then, the volume knob goes from -30dB to +6dB. Should it
> be set only by ear, or is there a logic behind it, such
> as nominal output of the 02R or something else ?

First and foremost, the crossover frequency and subwoofer level controls
should be set for best sound.

Furthermore, if you're a well-experienced recordist, you should have
already:

(a) Figured this out by hooking the sub up and playing with the controls

(b) Arrived at reasonable settings or known the reason why, using just your
ears and recordings that you chose.

The argument goes something like this - as a recordist and sound mixer your
job is to mix and match different musical sounds so that they mix and match
together in a pleasing and sensible way. Matching a subwoofer up with
satellite speakers is something like mixing a guitar and bass.

Just looking at its specs and remembering what the last NS10 I ever heard
sounded like, the range of probable crossover frequencies would be 60-150
Hz. This well depend on where the NS10s are located. Put them up in the
soffet, and their bass response wil be extended downward quite a bit.

Subwoofer crossover setting and positioning is highly dependent on the upper
range speakers. You have two goals - extending the bass response extension
of the system and increasing the dynamic range of the system particularly in
the mid-bass, by offloading low frequency power handling requirements from
the satellites to the subwoofer.

The more capable the satellites are on the bass end, the lower you can set
the crossover frequency.

The higher you set the crossover frequency, the more critical it becomes
that the satellites not be widely separated, and that the subwoofer be in
the approximate center of the two satelltes.

The usual way to set up a subwoofer crossover is to play a recording with
scales or other ascending or descending series of bass notes and adjusting
the crossover so that the notes retain their basic timber and loudness as
the frerquencies go up and down.

If you search around the web you can find CDs that are designed to help
people set up subwoofers. Many come out of the carsound world, but even so
their basic idea is reasonable. These CDs are composed of tones or better
yet warble tones that have constant ampltude but increase or decrease in
frequencies. In some cases they are slow sweeps.

If you're handy with a DAW, you can make your own test CDs for this
purpose.

[Peter Larsen[_3_]]

Arny Krueger wrote:

> The usual way to set up a subwoofer crossover is to play a recording
> with scales or other ascending or descending series of bass notes and
> adjusting the crossover so that the notes retain their basic timber
> and loudness as the frerquencies go up and down.

Male voice works well, turn sub up until audible, then turn down until
inaudible since it should not be separately audible on that source. 115 Hz
is a good "first bet" for x-over with small boxes, imo they should have an
octave of response below the chosen cross-ver.

Be aware that the subwoofer will appear to be a couple of dB too loud - or
needs to be 2 dB softer - in case the pathlength to it is too much shorter
than the pathlength to the tops.

A single subwoofer can not reproduce low frequencies that are out of phase,
if you are a classical guy it matters, if you do track building it probably
doesn't.

Kind regards

Peter Larsen