I was looking for a little advice on the amount of subwoofer level
control in a head unit. I had my eyes on a Pioneer DEH-P7600MP, which
has a subwoofer level control of -6db to +6db. This doesn't sound
like much control to me. I typically like it loud and pumping, but
sometimes you want to be able to actually talk to someone in the car
and you want to turn the level way down, but not off. I'm afraid that
if I set the gain on the amp to be just slightly audible at the -6
setting, then it won't be pushing the limits at the +6 setting. In my
last car, I ran a separate EQ, so I really had full infinite control
over the level. This car doesn't have a spot for the EQ, so I'm
trying to get away without it. Also, I kind of liked the idea that
Sony gives you a -10db to +10db range, though I'm partial to the
Pioneer. Any thoughts?

Thanks,
Roby2222

Roby2(x4),

Keep in mind that once you hit a difference of 3db, your sound is now
twice as loud as it was before. For the most part, you should be looking
at setting your amp to be loud enuf without the bass boost. Once you are
happy with that (don't kill your amp on the gains), then play with the
boost.

P.S. - Start by keeping your boost level at 0db when working with your
amp levels.

-----------------------------------------------------
BlaqAltima - http://www.sounddomain.com/id/blaqaltima
-----------------------------------------------------

Roby2222 wrote:

I was looking for a little advice on the amount of subwoofer level
control in a head unit. I had my eyes on a Pioneer DEH-P7600MP, which
has a subwoofer level control of -6db to +6db. This doesn't sound
like much control to me. I typically like it loud and pumping, but
sometimes you want to be able to actually talk to someone in the car
and you want to turn the level way down, but not off. I'm afraid that
if I set the gain on the amp to be just slightly audible at the -6
setting, then it won't be pushing the limits at the +6 setting. In my
last car, I ran a separate EQ, so I really had full infinite control
over the level. This car doesn't have a spot for the EQ, so I'm
trying to get away without it. Also, I kind of liked the idea that
Sony gives you a -10db to +10db range, though I'm partial to the
Pioneer. Any thoughts?

Thanks,
Roby2222

wrote in message
news
Roby2(x4),

Keep in mind that once you hit a difference of 3db, your sound is now
twice as loud as it was before.

No, that's not right. You're probably thinking of power consumption. This
decibel thing is confusing because they made it logarithmic. A difference of
10dB is considered a doubling of perceived volume. But this requires a ten-fold
increase in power requirement. But if you want an increase of 3dB, then you
need twice the power. For example.

90dB - twice as loud as 80dB, requires 10x the power
93dB - a "little" louder than 90dB, requires 2x the power
100dB - twice as loud as 90dB, four times as loud as 80dB, requires 10x the
power of 90dB, requires 100x the power of 80dB

This is why going from an amp of 100 watts to an amp of 200 watts, sound quality
and all else being equal, really doesn't buy you a whole lot.

Keep in mind that once you hit a difference of 3db, your sound is now
twice as loud as it was before.

No, that's not right. You're probably thinking of power consumption. This
decibel thing is confusing because they made it logarithmic. A difference of
10dB is considered a doubling of perceived volume. But this requires a ten-fold
increase in power requirement. But if you want an increase of 3dB, then you
need twice the power. For example.

90dB - twice as loud as 80dB, requires 10x the power
93dB - a "little" louder than 90dB, requires 2x the power
100dB - twice as loud as 90dB, four times as loud as 80dB, requires 10x the
power of 90dB, requires 100x the power of 80dB

This is why going from an amp of 100 watts to an amp of 200 watts, sound quality
and all else being equal, really doesn't buy you a whole lot.

This isn't entirely true. First of all, the 10dB number you cite is
essentially for subwoofer frequencies, and not for higher frequencies.
Perceived doubling approaches about 5dB at higher frequencies. Yes, I
know the original discussion was about subs, but I thought I'd add this as
a clarification rather than a rebuttal. Second, doubling power can be
quite significant, actually. The distortion produced by the 200 watt amp
at a given volume level (nearing the output capabilities of the amplifier)
is much less than the distortion produced by a 100 watt amp trying to
attain that same output level.

Your point is well taken, but I think further clarification was in order.
But to echo your sentiment, I think this illustrates just how important
speaker sensitivity is, eh?

"MZ" wrote in message
...

Your point is well taken, but I think further clarification was in order.
But to echo your sentiment, I think this illustrates just how important
speaker sensitivity is, eh?

Sure, and other things. We could go on because the issue is pretty
complicated, as you allude to. But the original post was just flat wrong,
that's why I mentioned it. BTW, I hadn't heard the 5dB figure for high
frequencies. My understanding was that the 10dB figure for sound doubling
was a sort of average for the whole frequency spectrum (e.g. pink noise or
white noise type of sound.)

Sure, and other things. We could go on because the issue is pretty
complicated, as you allude to. But the original post was just flat wrong,
that's why I mentioned it. BTW, I hadn't heard the 5dB figure for high
frequencies. My understanding was that the 10dB figure for sound doubling
was a sort of average for the whole frequency spectrum (e.g. pink noise or
white noise type of sound.)

Sorry! After re-reading what I wrote, I see that I got it backwards! At
1kHz, the "10dB" rule is true, and this more or less extends down to 100Hz.
At subwoofer frequencies, however, a smaller increase in power leads to the
same difference in perceived loudness. So an increase in 10dB at 1kHz
results in a doubling of perceived loudness, but at 60Hz it's only about
3dB. Look up "Fletcher-Munson curves" or "Robinson-Dadson" in a google
search.

Sorry! After re-reading what I wrote, I see that I got it backwards! At
1kHz, the "10dB" rule is true, and this more or less extends down to
100Hz.
At subwoofer frequencies, however, a smaller increase in power leads to
the
same difference in perceived loudness. So an increase in 10dB at 1kHz
results in a doubling of perceived loudness, but at 60Hz it's only about
3dB. Look up "Fletcher-Munson curves" or "Robinson-Dadson" in a google
search.

I've got it he http://mdz.no-ip.org/audio/docs/fletcher-munson.gif

Each curve is an equal loudness contour, in units of phons. It's a
logarithmic measure, so adding 10 phons is equivalent to doubling perceived
loudness. As you can see, 10 phons at 1kHz corresponds to 10dB. But at
lower frequencies, it's closer to 3-5dB.

To get to your initial question: what about using an amp with a remote
bass knob (gain)?
This will be easier than going through the HU menu everytime to get to
the sub setting if its only the sub volume your after..........


--
Mervin
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