2 subs one box

[Daniel Snooks]

Dan Berry wrote
> Hi,
> I'm building a speaker box to hold two 10" subs fed by a mono amp. My
> initial plans have them in separate compartments with about 1 cf of space
> for each.

Have you accounted for the space that the speakers will take up?

> I've been reading about dual subs in the same enclosure and am
> considering placing both subs in the same volume very close to each other.
> My thinking is the 2 subs will act like a larger sub giving me a little
more
> low frequency response.

It won't make a difference if they are in separate spaces or together. There
are a number of reasons to stay with separate though, including the effect
on one speaker it the other stops working.

> I don't want to enter competitions or make huge
> SPL's, just looking for well rounded sound. Is this a valid technique?
> What am I not thinking of?

Why are you using about 1cf of space for each? How are you going to wire the
subs?

--
Regards,
Dan Snooks

[Dan Berry]

Hi,
I'm building a speaker box to hold two 10" subs fed by a mono amp. My
initial plans have them in separate compartments with about 1 cf of space
for each. I've been reading about dual subs in the same enclosure and am
considering placing both subs in the same volume very close to each other.
My thinking is the 2 subs will act like a larger sub giving me a little more
low frequency response. I don't want to enter competitions or make huge
SPL's, just looking for well rounded sound. Is this a valid technique?
What am I not thinking of?
Thanks,
Dan

[-E-F-F-E-N-D-I-]

a perfect setup. you are right about 2 subs vs just one. the more air you
move the louder sound you get. if the lowest possible frequency performance
is what you are after then a sealed box is the best choice. if you are going
to do a sealed make sure you get the right power feeding your subs because a
lot of people dont like their first attempts at making a enclosure simply
because their subs need more power to perform well in a sealed enclosure.
that and make sure the box has no air leaks. im running a sealed box with
two 10"s and about 0.75cuFt for each and it sounds louder and cleaner than
my dual 10" bandpass enclosure with 1.2cuFt each in my other car.

EFFENDI

"Dan Berry" > wrote in message
...
> Hi,
> I'm building a speaker box to hold two 10" subs fed by a mono amp. My
> initial plans have them in separate compartments with about 1 cf of space
> for each. I've been reading about dual subs in the same enclosure and am
> considering placing both subs in the same volume very close to each other.
> My thinking is the 2 subs will act like a larger sub giving me a little
more
> low frequency response. I don't want to enter competitions or make huge
> SPL's, just looking for well rounded sound. Is this a valid technique?
> What am I not thinking of?
> Thanks,
> Dan
>
>

[Dan Berry]

"Daniel Snooks" > wrote in message
...
> Dan Berry wrote
> > Hi,
> > I'm building a speaker box to hold two 10" subs fed by a mono amp. My
> > initial plans have them in separate compartments with about 1 cf of
space
> > for each.
>
> Have you accounted for the space that the speakers will take up?

Yes, the speakers take up 75.3 cubic inches each.

> > I've been reading about dual subs in the same enclosure and am
> > considering placing both subs in the same volume very close to each
other.
> > My thinking is the 2 subs will act like a larger sub giving me a little
> more
> > low frequency response.
>
> It won't make a difference if they are in separate spaces or together.
There
> are a number of reasons to stay with separate though, including the effect
> on one speaker it the other stops working.
>
> > I don't want to enter competitions or make huge
> > SPL's, just looking for well rounded sound. Is this a valid technique?
> > What am I not thinking of?
>
> Why are you using about 1cf of space for each? How are you going to wire
the
> subs?

Kicker recommends a minimum of .8 CF for a sealed enclosure with a max of 3
CF. They
quote "As the sealed enclosure volumes increase, the response will shift
from high impact
bass to a smoother and more extended low end."

Since I'm constrained by space, I have a total interior volume of about 2.5
CF to share with the subs. The amp is capable of providing 400 watts into 2
ohms, but I'll wire the 2 speakers in parallel to present a 4 ohm load. The
speakers are 4 ohm dual voice cone (both 4 ohm cones in series = 8ohm).

>
> --
> Regards,
> Dan Snooks
>

I'm still trying to decide between mounting the amp in the box, how far to
recess it into the box (loosing interior volume by doing so), and whether to
mount the speakers in a shared space, or in separate space at either end of
the enclosure. This will fit behind the rear seat of a crew cab truck btw.


Thanks!
Dan

[Dan Berry]

"-E-F-F-E-N-D-I-" > wrote in message
.. .
> a perfect setup. you are right about 2 subs vs just one. the more air you
> move the louder sound you get. if the lowest possible frequency
performance
> is what you are after then a sealed box is the best choice. if you are
going
> to do a sealed make sure you get the right power feeding your subs because
a
> lot of people dont like their first attempts at making a enclosure simply
> because their subs need more power to perform well in a sealed enclosure.
> that and make sure the box has no air leaks. im running a sealed box with
> two 10"s and about 0.75cuFt for each and it sounds louder and cleaner than
> my dual 10" bandpass enclosure with 1.2cuFt each in my other car.
>
> EFFENDI

Clean and accurate is what I'm looking for. My system will play much louder
than I ever want to hear it.

Thanks,
Dan

[-E-F-F-E-N-D-I-]

"Daniel Snooks" > wrote in message
...
> -E-F-F-E-N-D-I- wrote
> > a perfect setup. you are right about 2 subs vs just one.
>
> Looking at what he wrote, he is not right. Placing both subs in separate
> compartments will give the same effect as having them in a single larger
> compartment. Structurally speaking, he is better off building the box with
> two separate compartments.
>
my bad, i didnt read what he wrote. d'oh!! of course it is the same if they
are in seperate compartments. I thought it was a one sub vs two thing. ah
well it was 3 am when i wrote that.

> > the more air you
> > move the louder sound you get. if the lowest possible frequency
> performance
> > is what you are after then a sealed box is the best choice.
>
> He never mentioned that he was trying to acheive the lowest possible
> frequency performance, only that he wanted well rounded sound. What type
of
> box he should build depends more on the rest of his system (mids, xover
> points, type of vehicle, etc.) and on how good he is at fabricating. A
> sealed box will be easier to build, but if he has strong midrange speakers
> and lots of space then he may be better off with ported or bandpass.
>
he said he wants a "little more low frequency response" im just reccomending
what is the cheapest, easiest and most effective type of enclosure. a sealed
enclosure can always still be crossed over to let the midbass play the
higher frequencies. a ported or bandpass is very difficult to build tune and
is not always the best for low end extension. a sealed wil give him a
flatter response curve than any other type of enclosure.

> > if you are going
> > to do a sealed make sure you get the right power feeding your subs
because
> a
> > lot of people dont like their first attempts at making a enclosure
simply
> > because their subs need more power to perform well in a sealed
enclosure.
>
> Why would the subs need more power to perform well in a sealed enclosure?
>
generally people do not run the right power to their subs in a sealed
enclosure. a bandpass and ported box you can get away with less power
feeding the subs and it will still perform as well as a higher power setup.
this is all due to physics and the effiency of the subwoofer in different
types of enclosures. some perform better in differen types. based on my
experiences i always run more power to subs in a sealed enclosure and the
subs just perform better when they have enough power. there is a lot of air
presure changes inside a sealed enclosure that the sub needs to have enough
power to (for lack of better term) control, otherwise it just wont sound
right.

BTW who the are you Dan Snook i never heard of you in r.a.c. before.?

> --
> Regards,
> Dan Snooks
>
>

[Daniel Snooks]

-E-F-F-E-N-D-I- wrote
> he said he wants a "little more low frequency response" im just
reccomending
> what is the cheapest, easiest and most effective type of enclosure. a
sealed
> enclosure can always still be crossed over to let the midbass play the
> higher frequencies. a ported or bandpass is very difficult to build tune
and
> is not always the best for low end extension. a sealed wil give him a
> flatter response curve than any other type of enclosure.

My point is exactly that ... A sealed will give him a flatter response
curve. If he wants a little more low frequency response he would do better
with a ported enclosure, nice little hump at the tuning point (specially if
he tunes it down near 35Hz ish)

> generally people do not run the right power to their subs in a sealed
> enclosure. a bandpass and ported box you can get away with less power
> feeding the subs and it will still perform as well as a higher power
setup.

I don't see your point ... it seems like you are comparing a ported with
less power to a sealed with more power

> this is all due to physics and the effiency of the subwoofer in different
> types of enclosures. some perform better in differen types.

again ... I don't see your point. The way a speaker is designed impacts the
type of enclosure it is suited to, that I agree with ... you are suggesting
to him that giving extra power to some 10" unknown subs will improve the way
the sound in a sealed enclosure, this assumes too much.

> based on my
> experiences i always run more power to subs in a sealed enclosure and the
> subs just perform better when they have enough power. there is a lot of
air
> presure changes inside a sealed enclosure that the sub needs to have
enough
> power to (for lack of better term) control, otherwise it just wont sound
> right.

Why?

There is a lot of air pressure changes inside any type of enclosure, that is
the purpose of the entire exercise. Seeing as we don't have specific model
information to deal with we will use a pair of 10" subs that are rated to
handle 250W RMS each as an example.
If you put them in a sealed enclosure and run them with a 500W RMS amp, they
will sound exactly the same as if you use a 800W RMS amp. The only real
difference is that the 800W amp won't have to work as hard to drive the subs
to their limit.

> BTW who the are you Dan Snook i never heard of you in r.a.c. before.?

I have always wondered why people discard the 's' at the end of my name ...
Snooks. Happens all the time :)
I have been keeping an eye on RAC for about 6 years or so, not constantly,
but as high speed internet access becomes available to me.

I am curious as to why you ask who I am. Here is one possible answer (not
sure what answer you were looking for)

I am 26, an electrican living near Toronto, Canada, and have extensive
hands-on knowledge of computers (no formal training) but for the most part
it is limited to hardware. Some of my hobbies include, audio/video systems,
classic cars, computers, car audio, modding cars, and weapons. I am married,
no kids, 2 dogs, own a house, '69 GMC 1500, '85 Firebird, '94 Sunbird, and
'03 Cavalier. That's all I can think of for now ...


--
Regards,
Dan Snooks

[-E-F-F-E-N-D-I-]

"Daniel Snooks" > wrote in message
.. .
> -E-F-F-E-N-D-I- wrote
> > he said he wants a "little more low frequency response" im just
> reccomending
> > what is the cheapest, easiest and most effective type of enclosure. a
> sealed
> > enclosure can always still be crossed over to let the midbass play the
> > higher frequencies. a ported or bandpass is very difficult to build tune
> and
> > is not always the best for low end extension. a sealed wil give him a
> > flatter response curve than any other type of enclosure.
>
> My point is exactly that ... A sealed will give him a flatter response
> curve. If he wants a little more low frequency response he would do better
> with a ported enclosure, nice little hump at the tuning point (specially
if
> he tunes it down near 35Hz ish)

You are right there. A ported is the most efficient design. However a sealed
is a more "accurate" design. The poster said they are not looking for
maximum SPL just a smooth low end. Many will aregue against the
disadvantages and advantages of sealed vs ported vs other enclosure types.
Its been argued to death on r.a.c. This is the OP's first box building
attempt from what a gather. A sealed will undoubtedly be the cheapest,
easiest, and most effective.
>
> > generally people do not run the right power to their subs in a sealed
> > enclosure. a bandpass and ported box you can get away with less power
> > feeding the subs and it will still perform as well as a higher power
> setup.
>
> I don't see your point ... it seems like you are comparing a ported with
> less power to a sealed with more power

I am comparing them. A lower powered ported enclosure might sound louder at
a given frequency, but a sealed enclosure will generally, need more power to
match the output at the tuned frequency of a ported box.
>
> > this is all due to physics and the effiency of the subwoofer in
different
> > types of enclosures. some perform better in differen types.
>
> again ... I don't see your point. The way a speaker is designed impacts
the
> type of enclosure it is suited to, that I agree with ... you are
suggesting
> to him that giving extra power to some 10" unknown subs will improve the
way
> the sound in a sealed enclosure, this assumes too much.

yes it does. i am not suggesting overpowering. simply reccomending to supply
the subs with rated power if at all possible.
>
> > based on my
> > experiences i always run more power to subs in a sealed enclosure and
the
> > subs just perform better when they have enough power. there is a lot of
> air
> > presure changes inside a sealed enclosure that the sub needs to have
> enough
> > power to (for lack of better term) control, otherwise it just wont sound
> > right.
>
> Why?
>
> There is a lot of air pressure changes inside any type of enclosure, that
is
> the purpose of the entire exercise. Seeing as we don't have specific model
> information to deal with we will use a pair of 10" subs that are rated to
> handle 250W RMS each as an example.
> If you put them in a sealed enclosure and run them with a 500W RMS amp,
they
> will sound exactly the same as if you use a 800W RMS amp. The only real
> difference is that the 800W amp won't have to work as hard to drive the
subs
> to their limit.

Really? I always thought that increasing power increased the dB output of
the sub. More power = more sound? correct me if i am wrong there. All I am
simply stating and what was the intended response to the Original Poster. In
which his original post he said "What am I not thinking of?" I am reminding
them to use the correct power to drive the subs in the enclosure they plan
to build. I am not suggesting overpowering the subs, just getting as close
to RMS or max wattage ratings of the subwoofers. This guarantees better
result in the end when everything is matched.

>
> > BTW who the are you Dan Snook i never heard of you in r.a.c. before.?
>
> I have always wondered why people discard the 's' at the end of my name
....
> Snooks. Happens all the time :)
> I have been keeping an eye on RAC for about 6 years or so, not constantly,
> but as high speed internet access becomes available to me.
>
> I am curious as to why you ask who I am. Here is one possible answer (not
> sure what answer you were looking for)
>
> I am 26, an electrican living near Toronto, Canada, and have extensive
> hands-on knowledge of computers (no formal training)___ {{Me
Neither!!}}___ but for the most part
> it is limited to hardware. Some of my hobbies include, audio/video
systems,
> classic cars, computers, car audio, modding cars, and weapons. I am
married,
> no kids, 2 dogs, own a house, '69 GMC 1500, '85 Firebird, '94 Sunbird, and
> '03 Cavalier. That's all I can think of for now ...

coo im from vancouver but im slangin down in southern california right now.
see you around.
>
>
> --
> Regards,
> Dan Snooks
>
>

[Dan Berry]

"Daniel Snooks" > wrote

> To the OP ... what equipment are you using? Do you have the time,
patience,
> and tools to try a ported design?
>

I have a full woodworking shop so building any size speaker would be fairly
straighforward, but the box is nearly done. I understand there is quite a
bit of science involved in getting the sizes right for a ported box and that
led me to choose a sealed enclosure.

Thanks,
Dan