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bob zee bob zee is offline
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Default Noob Ohm Issue 2 vs 8

I just recently aquired a few components -an amp and 2 subs. I am not
very interested in SPL. I am very interested in SQ.

Here is the amp that I have:
CrunchPZi 175.4 -1000 Watt (peak) 4 Channel Amplifier
and the specs for this amp:
1000W 2 / 3 / 4-Channel A/B Class Amplifier
175W x 4-Ch @ 4-Ohms or
250W x 4-Ch @ 2-Ohms or
500W x 2-Ch @ 4-Ohms Dynamic Music Watts

I have (2) of these subs:
Pioneer TS-W256DVC10" Dual Voice Coil Component Subwoofer
and the specs:
10" Component Subwoofers with 800 Watts Max. Power
350 Watts Nominal Power
4-Ohm Dual Voice Coil (DVC)
Recommended Enclosure Use: 0.65 ~ 1.25 Cubic Feet

My intentions are to run this amp in (2) channel mode - (1) channel for
each sub. My question is this: Since these are dual voice coil
speakers, should I wire them as 2ohm or wire them as 8ohm? I don't
care to play my music extremely loud - I just want some dynamics,
clarity and quality!

I am really hoping someone can make me feel better about this mess. I
sure get myself into some predicaments.

bob z.

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D.Kreft D.Kreft is offline
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Default Noob Ohm Issue 2 vs 8

On Oct 12, 9:04 am, "bob zee" wrote:

Here is the amp that I have:
CrunchPZi 175.4 -1000 Watt (peak) 4 Channel Amplifier
and the specs for this amp:
1000W 2 / 3 / 4-Channel A/B Class Amplifier
175W x 4-Ch @ 4-Ohms or
250W x 4-Ch @ 2-Ohms or
500W x 2-Ch @ 4-Ohms Dynamic Music Watts


I don't know what a "Dynamic Music Watt" is.

My intentions are to run this amp in (2) channel mode - (1) channel for
each sub. My question is this: Since these are dual voice coil
speakers, should I wire them as 2ohm or wire them as 8ohm? I don't
care to play my music extremely loud - I just want some dynamics,
clarity and quality!


It doesn't look like you can take your 4-channel amp and run it in
2-channel (bridged) mode on a 4 Ohm load. You'll need to wire the
individual coils in series. See "1 DVC driver with Voice Coils in
Series" at
http://mobile.jlaudio.com/support_pages.php?page_id=161 and do that
twice.

-dan

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Default Noob Ohm Issue 2 vs 8

bob zee wrote:
I just recently aquired a few components -an amp and 2 subs. I am not
very interested in SPL. I am very interested in SQ.

Here is the amp that I have:
CrunchPZi 175.4 -1000 Watt (peak) 4 Channel Amplifier
and the specs for this amp:
1000W 2 / 3 / 4-Channel A/B Class Amplifier
175W x 4-Ch @ 4-Ohms or
250W x 4-Ch @ 2-Ohms or
500W x 2-Ch @ 4-Ohms Dynamic Music Watts

I have (2) of these subs:
Pioneer TS-W256DVC10" Dual Voice Coil Component Subwoofer
and the specs:
10" Component Subwoofers with 800 Watts Max. Power
350 Watts Nominal Power
4-Ohm Dual Voice Coil (DVC)
Recommended Enclosure Use: 0.65 ~ 1.25 Cubic Feet

My intentions are to run this amp in (2) channel mode - (1) channel for
each sub. My question is this: Since these are dual voice coil
speakers, should I wire them as 2ohm or wire them as 8ohm? I don't
care to play my music extremely loud - I just want some dynamics,
clarity and quality!

I am really hoping someone can make me feel better about this mess. I
sure get myself into some predicaments.


From the specs you listed, it doesn't look like that amp will like a two-ohm
load running in two-channel mode, so you'll pretty much have to go with the
eight-ohm configuration.
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Default Noob Ohm Issue 2 vs 8


D.Kreft wrote:

500W x 2-Ch @ 4-Ohms Dynamic Music Watts


I don't know what a "Dynamic Music Watt" is.


I don't either! Sure sounds cool, though, doesn't it?
:~)


It doesn't look like you can take your 4-channel amp and run it in
2-channel (bridged) mode on a 4 Ohm load. You'll need to wire the
individual coils in series. See "1 DVC driver with Voice Coils in
Series" at
http://mobile.jlaudio.com/support_pages.php?page_id=161 and do that
twice.

-dan


Then to keep it simple I am going to assume (1) channel and (1) sub
like in the picture. My amp will then be pushing a sub with an 8 Ohm
load. Is this correct? This will not be any cause for me to worry, I
hope.

Thanks!
bob z.

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Default Noob Ohm Issue 2 vs 8


Matt Ion wrote:


From the specs you listed, it doesn't look like that amp will like a two-ohm
load running in two-channel mode, so you'll pretty much have to go with the
eight-ohm configuration.


That is what I figured. I was really just looking for some
confirmation.
What will 8ohm do to my SQ or am I worrying for no reason?

Thanks!
bob z.



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Default Noob Ohm Issue 2 vs 8

bob zee wrote:

Then to keep it simple I am going to assume (1) channel and (1) sub
like in the picture. My amp will then be pushing a sub with an 8 Ohm
load. Is this correct?


Just to be *crystal* clear...

0. You have a four-channel amp--we'll call those channels A, B, C, and
D.

1. Bridge A + B together to make channel "AB".
Bridge C + D together to make channel "CD".
You now effectively have a "two-channel" amp.

2. Wire the VC on one driver in series per the diagram to which I
pointed you.
Do the same with the other driver.
You now effectively have two 8 Ohm drivers.

3. Take one 8 Ohm driver and hook it up to channel AB.
Take the other driver and hook it up to channel CD.
You now have a two-channel amp powering two 8 Ohm speakers.

4. Relax.

-dan

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Default Noob Ohm Issue 2 vs 8


D.Kreft wrote:


Just to be *crystal* clear...

4. Relax.

-dan



Thanks a ton. You rock.

bob z.

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Default Noob Ohm Issue 2 vs 8

It will cut your power output in half. Seeing the wattage that you have listed
for this amp is in "Peak Power" you should get around 50 - 60 watts RMS per
coil cranked up. As for your SQ, I have always found that under powering a sub
sounds like a wet fart and I have also found this to be even more true when
using lite duty amps such as Crunch. My advice is to try it out for yourself
and see how you like it.


In article .com, "bob zee"
wrote:



That is what I figured. I was really just looking for some
confirmation.
What will 8ohm do to my SQ or am I worrying for no reason?

Thanks!
bob z.

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Matt Ion Matt Ion is offline
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Default Noob Ohm Issue 2 vs 8

D.Kreft wrote:
On Oct 12, 9:04 am, "bob zee" wrote:


Here is the amp that I have:
CrunchPZi 175.4 -1000 Watt (peak) 4 Channel Amplifier
and the specs for this amp:
1000W 2 / 3 / 4-Channel A/B Class Amplifier
175W x 4-Ch @ 4-Ohms or
250W x 4-Ch @ 2-Ohms or
500W x 2-Ch @ 4-Ohms Dynamic Music Watts



I don't know what a "Dynamic Music Watt" is.


I would guess it's Crunch's non-technical term for "RMS".
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Default Noob Ohm Issue 2 vs 8

Captain_Howdy wrote:
It will cut your power output in half. Seeing the wattage that you have listed
for this amp is in "Peak Power" you should get around 50 - 60 watts RMS per
coil cranked up. As for your SQ, I have always found that under powering a sub
sounds like a wet fart and I have also found this to be even more true when
using lite duty amps such as Crunch. My advice is to try it out for yourself
and see how you like it.


In article .com, "bob zee"
wrote:


That is what I figured. I was really just looking for some
confirmation.
What will 8ohm do to my SQ or am I worrying for no reason?


One other option would be to run each pair of channels in mono rather than
bridged mode, then wire each coil individually to each channel, but that really
won't give you any more power, and can be tricky when setting levels properly to
match.

Frankly, you'll get more output and possibly cleaner sound by wiring the subs
for two ohms (coils in parallel) and simply running them off two of the four
channels without bridging. The other two channels are left unused... or use
them for a pair of your full-range speakers, if you don't already have an amp
for those.


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Default Noob Ohm Issue 2 vs 8


Captain_Howdy wrote:
It will cut your power output in half. Seeing the wattage that you have listed
for this amp is in "Peak Power" you should get around 50 - 60 watts RMS per
coil cranked up. As for your SQ, I have always found that under powering a sub
sounds like a wet fart and I have also found this to be even more true when
using lite duty amps such as Crunch. My advice is to try it out for yourself
and see how you like it.



I figured this was a light-duty amp considering the cost. I am on a
budget, so this is what I could afford. Depending on how this setup
sounds, I can see myself transferring this amp to the other car - a car
that has 4 speakers that will utilize all 4 channels of this amp.
I really appreciate your advice. I was a little afraid to ask what
wattage would end up at each coil. I didn't want it to sound like I
was just in it for the big numbers. I really like a nice tight, clean,
punchy sound in my music.

There I go... starting to worry again. Must relax, must relax, must
relax.
:~)

Thanks!
bob z.

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bob zee wrote:

That is what I figured. I was really just looking for some
confirmation.
What will 8ohm do to my SQ or am I worrying for no reason?


Bob, take a deep breath. Use the force. Go to your happy place. Relax.

Cross each bridge as you come to them--don't try to get it perfect the
first time around because, well, quite frankly it sounds like this
might be your first "go" at system building and it might not sound
perfect the first time around. Even systems setup by experts typically
need tweaking and tuning to get them to sound just right...and
sometimes even that doesn't work.

Just have fun with it. Follow carefully the instructions I've given you
thus far, follow the wiring diagrams, and check everything you do two
or three times. Modern amplifiers have lots of protection circuits in
them to keep you from doing something obcenely stupid and destroying
your amplifier. That's not to say you can be careless, only that you
don't have to sweat bullets here--it's all just a matter of "putting
tab A into slot B", tightening some screws and vacuuming-up after
yourself when you're done.

Running in 8 Ohms mono is effectively the same as running in 4 Ohms
stereo. While you won't get the absolute most power out of your
amplifier, you will definitely run cooler, you'll usually have greater
dynamic headroom and the damping factor will be higher. In short, sound
quality can actually be *better* with a higher load than with a lower
load. If you find that the subs aren't quite loud enough to keep up
with the rest of your system (or with your expectations), THEN you can
fall back to using just half of your amp bridged on a 4 Ohm
load...which will be louder but *might* not sound as good--it's all
very subjective and ultimately only you are going to be able to tell if
it "sounds good" or not. We're just a bunch of talking heads and it's
not our ears in your car.

-dan

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D.Kreft wrote:


Bob, take a deep breath. Use the force. Go to your happy place. Relax.

Cross each bridge as you come to them--don't try to get it perfect the
first time around because, well, quite frankly it sounds like this
might be your first "go" at system building and it might not sound
perfect the first time around.
-dan



Definitely my first real "go" at system building. Thank you for the
positive encouragement. I'll be in the garage this weekend cuttin,
strippin, and crimpin...
:~)

Thanks so much
bob z.

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Default Noob Ohm Issue 2 vs 8

bob zee wrote:
I just recently aquired a few components -an amp and 2 subs. I am not
very interested in SPL. I am very interested in SQ.

Here is the amp that I have:
CrunchPZi 175.4 -1000 Watt (peak) 4 Channel Amplifier
and the specs for this amp:
1000W 2 / 3 / 4-Channel A/B Class Amplifier
175W x 4-Ch @ 4-Ohms or
250W x 4-Ch @ 2-Ohms or
500W x 2-Ch @ 4-Ohms Dynamic Music Watts

bob z.


You didn't list the specs for 3-Ch mode..
I'd run 3-Ch mode. If available...
I'd wire each sub for 8-Ohms
Hook both up to the bridged channel for a 4-Ohm load.
Use the 2 stereo channels for the front speakers.


FasDeth
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Default Noob Ohm Issue 2 vs 8

D.Kreft wrote:

Cross each bridge as you come to them--don't try to get it perfect the
first time around because, well, quite frankly it sounds like this
might be your first "go" at system building and it might not sound
perfect the first time around. Even systems setup by experts typically
need tweaking and tuning to get them to sound just right...and
sometimes even that doesn't work.

Just have fun with it.


What he said! No matter what you do, Bob, it should be an improvement over NO
subs, so you really can't go wrong at this point


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FasDeth wrote:


You didn't list the specs for 3-Ch mode..
I'd run 3-Ch mode. If available...
I'd wire each sub for 8-Ohms
Hook both up to the bridged channel for a 4-Ohm load.
Use the 2 stereo channels for the front speakers.


FasDeth


I can't find the specs for the 3-Channel mode. Crunch doesn't want us
to know this info!
:-(

Good idea, though. I just don't have decent speakers up front yet. My
system will be lop-sided for a little while.

bob z.

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Matt Ion wrote:


What he said! No matter what you do, Bob, it should be an improvement over NO
subs, so you really can't go wrong at this point


Heck yeah. I have a 90 minute drive to work (same back home) and my
stock stereo is beginning to clip (?) and cut-out sooner and sooner
everyday. I thought it was overheating, but it was 34° this morning.
I normally keep the volume at about 75% of full for my whole drive.
Today, I could obtain no more than 15 minutes of 75% and then it would
only 'clear up' at 50% volume.


bob z.
(2003 honda accord 2-door - stock 160w stereo)

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Default Noob Ohm Issue 2 vs 8

bob zee wrote:
Matt Ion wrote:


What he said! No matter what you do, Bob, it should be an improvement over NO
subs, so you really can't go wrong at this point



Heck yeah. I have a 90 minute drive to work (same back home) and my
stock stereo is beginning to clip (?) and cut-out sooner and sooner
everyday. I thought it was overheating, but it was 34° this morning.
I normally keep the volume at about 75% of full for my whole drive.
Today, I could obtain no more than 15 minutes of 75% and then it would
only 'clear up' at 50% volume.


You know, if your stock system has no amp, I'd DEFINITELY recommend adding
one... like I said, you could run your subs wired for two ohms off two channels
of that amp, and your other speakers off the other two channels - even if you
have four speakers, you can wire the front and rear in parallel and run them off
the two remaining channels. I have a similar setup in my car with a Kenwood
four-channel amp: two channels running the front and rear speakers parallelled,
and the other two bridged to run a single 10" JL sub.
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Default Noob Ohm Issue 2 vs 8

bob zee wrote:
FasDeth wrote:


You didn't list the specs for 3-Ch mode..
I'd run 3-Ch mode. If available...
I'd wire each sub for 8-Ohms
Hook both up to the bridged channel for a 4-Ohm load.
Use the 2 stereo channels for the front speakers.


FasDeth



I can't find the specs for the 3-Channel mode. Crunch doesn't want us
to know this info!
:-(

Good idea, though. I just don't have decent speakers up front yet. My
system will be lop-sided for a little while.


Three-channel just means one pair of channels runs bridged, the other pair
doesn't, so you'd get 500W @ 4 ohms for the bridged pair (as per your listed specs:
175W x 4-Ch @ 4-Ohms or
250W x 4-Ch @ 2-Ohms or
500W x 2-Ch @ 4-Ohms Dynamic Music Watts

Specs-wise, wiring the subs that way (500W output) wouldn't be much different
than running them as two ohm, each on its own channel (at 250W each). There MAY
be some performance differences depending on whether the amp handles two-ohm
loads or bridged loads better, but probably nothing significant.
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Default Noob Ohm Issue 2 vs 8

FasDeth wrote:

bob zee wrote:
CrunchPZi 175.4 -1000 Watt (peak) 4 Channel Amplifier
and the specs for this amp:
1000W 2 / 3 / 4-Channel A/B Class Amplifier
175W x 4-Ch @ 4-Ohms or
250W x 4-Ch @ 2-Ohms or
500W x 2-Ch @ 4-Ohms Dynamic Music Watts


You didn't list the specs for 3-Ch mode..


I'd think that the output for 3-channel mode would be easily derived
from the stats he gave, namely:

175W x 2 (@ 4 Ohm) / 500W x 1 (@ 4 Ohm)

Although I'm thinking that 175 might be a typo that should be "125"
instead. The *actual* output may vary (I'm not familiar with Crunchy
amps), but I think it's a pretty safe bet to say it'll be pretty darn
close to what I'm throwing-out here.

-dan

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