I just installed my first sub into my car. Its a very cheap one ($9) 10"
with a 175W nominal rating and 350W max rating. I am very pleased with it.
It is actually a disco sub which is 8-ohm. I can't wait to put in another
one.

I put it into a variable volume box. I didn't have the TS for it so I had to
do this. It seems that the sub performs best when the box is max size which
is about 12"x12"x18" which is about 1.5cu ft.

Now I want to know:

1. Is wiring two 8-ohm svc subs in parallel the same as wiring two 4ohm dvc
(2x2ohm per sub) in a series parallel connection to create a 4-ohm load? I
think it should be?

2. Is nominal power rating the same as RMS power rating? (my 10" sub has a
nominal of 175W which (if it is RMS) is quite high for such a cheap sub.

3. What box setup should I use when I have two 10" subs. It doesnt seem that
I will be able to get the TS for them. Should I just buy a double 10" sealed
box or create something fancy like ported or solobaric boxes?

I listen to rock music 99.999% of the time. I want high SQ. If I can't get
SQ out of my subs then Id rather not have any. I don't want that cheap
distorted bass you hear coming out of taxis.

Please comment on everything.

pil wrote:

1. Is wiring two 8-ohm svc subs in parallel the same as wiring two 4ohm dvc
(2x2ohm per sub) in a series parallel connection to create a 4-ohm load? I
think it should be?

A 4 ohm DVC will actually be 4 x 2. Wired in series, each DVC sub will
have a total impedence of 8 ohms. Then if you wire the two subs in
parallel with each other, you'll have a 4 ohm load.

1
------------------
1 + 1
------- -------
4 + 4 4 + 4


If you wire two 8-ohm svc subs in parallel, you'll have a single 4 ohm load.

1
-------------
1 + 1
--- ---
8 8



(in case you missed that day in math, to solve a fraction which has a
fraction for the denominator, you "take the reciprocal", or just flip
the whole equation upside down.)

2. Is nominal power rating the same as RMS power rating? (my 10" sub has a
nominal of 175W which (if it is RMS) is quite high for such a cheap sub.

Nominal is another way of saying "peak" or "maximum". This is the
best-case scenario of power input or output. It is not RMS.

3. What box setup should I use when I have two 10" subs. It doesnt seem that
I will be able to get the TS for them. Should I just buy a double 10" sealed
box or create something fancy like ported or solobaric boxes?

This depends largely on the kind of music you listen to. In most cases,
a ported box delivers the most flexibility. When you start playing with
fruitcake box designs, you do alot of work for not alot of benefit.

Incidentally, the "solobaric" is a trademark of Stillwater Designs (the
gusy who make kicker). You're thinking "isobaric". Isobaric is not
really needed nowadays because new materials and more powerful amps have
nullified its advantage, which was greater power handling and stability
of the diaphragm.

I listen to rock music 99.999% of the time. I want high SQ. If I can't get
SQ out of my subs then Id rather not have any. I don't want that cheap
distorted bass you hear coming out of taxis.

If you have a big enough amp, go with a solid sealed box. Porting can be
a hassle if you don't have TS params, and ported boxes that aren't
designed right become "unloaded" at really low frequencies. Alot of rock
groups these days are piping low frequency sound into the mix to pump up
the overall "wall of sound" sensation. Some bands like Korn do it for
effect. Its really nasty when everything is jamming then that low tone
hits and you hear the flatulent sound of your sub bottoming out.

--
thelizman

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