Multi-Channel Amplifiers

[Auto]

Do any of you have a comment/experience with Multi-Channel Amps?

I'm looking at these two:

Infinity Reference 5760a
6-channel car amplifier: 56 watts RMS x 4 + 107 watts RMS x 2 at 4 ohms
(CEA-2006 Compliant)

Alpine MRV-F450
50 watts RMS x 4 + 200 watts RMS x 1 at 4 ohms

The idea would be to purchase one of these Amps. Then upgrade my
speakers and I'd have expansion for a Sub(s) later, if required.

The Infinity is about $300.00 while the Alpine is near $500.00. So the
Infinity looks better regarding price.

[[email protected]]

I have used a PPI 5 channel and am using a Hifonics Z8000 5 channel
now. The Hifonics has plenty of kick. Mine is 50x4 200x1 at 4 ohms and
100x4 300x1 at 2 ohms. The new version is 55x4 200x1 at 4 ohms and so
on. Great amp. I have been pushing it hard for about 18 months and
never had a problem.

[MOSFET]

"Auto" > wrote in message
ups.com...
> Do any of you have a comment/experience with Multi-Channel Amps?

8 years ago I used a single Soundstream Reference 705 (5 channel amp) in my
'97 Nissan Maxima. The install was show-quality and I competed many times
in local shows and took home a few trophies including a Novice 2nd place at
an IASCA Key Event in Portland, OR.

It was a great amp (it was subsequently stolen), but I would never buy an
amp like this again. Multi-channel amps, though often handy, REDUCE YOUR
FLEXIBILITY. It's a classic dilemma in car audio: On one hand, buying
multichannel amps often provide cost savings realized by enclosing
everything in one chassis, as well as making installations easier by taking
up less space as two comparable two-channel amps, and requiring only one set
of power/ground wires.

However, on the other hand, you have more flexibility by choosing each
stereo amp for the specific job it is to perform (150 watts per channel amp
for fronts and a 50 watt per channel amp for rear-fill, for instance).
Multichannel amps usually will give you X watts times 4 so you are stuck
with X watts for ALL your speakers.

The only thing that always remains the same about all my systems, is that
they all change from time to time. I think this goes for many of us.
Simple two channel amps give you much more flexibility if you decide to
change anything about your system in the future. What sometimes happens
with single amp solutions is that you may want to change just one part of
the installation. For instance, if I wanted to upgrade my sub amp to a
class D in my Maxima system (a very common upgrade), I would find that after
installing the Class D amp, I would then only be using four channels of the
five channels possible in the SS 705, thereby wasting resource. This does
not happen when all of your amps are two channel (you can simply sell your
old sub amp).

MOSFET

[Scott Gardner]

On Tue, 8 Mar 2005 19:33:50 -0800, "MOSFET" >
wrote:

>
>"Auto" > wrote in message
ups.com...
>> Do any of you have a comment/experience with Multi-Channel Amps?
>
>8 years ago I used a single Soundstream Reference 705 (5 channel amp) in my
>'97 Nissan Maxima. The install was show-quality and I competed many times
>in local shows and took home a few trophies including a Novice 2nd place at
>an IASCA Key Event in Portland, OR.
>
>It was a great amp (it was subsequently stolen), but I would never buy an
>amp like this again. Multi-channel amps, though often handy, REDUCE YOUR
>FLEXIBILITY. It's a classic dilemma in car audio: On one hand, buying
>multichannel amps often provide cost savings realized by enclosing
>everything in one chassis, as well as making installations easier by taking
>up less space as two comparable two-channel amps, and requiring only one set
>of power/ground wires.
>
>However, on the other hand, you have more flexibility by choosing each
>stereo amp for the specific job it is to perform (150 watts per channel amp
>for fronts and a 50 watt per channel amp for rear-fill, for instance).
>Multichannel amps usually will give you X watts times 4 so you are stuck
>with X watts for ALL your speakers.
>
>The only thing that always remains the same about all my systems, is that
>they all change from time to time. I think this goes for many of us.
>Simple two channel amps give you much more flexibility if you decide to
>change anything about your system in the future. What sometimes happens
>with single amp solutions is that you may want to change just one part of
>the installation. For instance, if I wanted to upgrade my sub amp to a
>class D in my Maxima system (a very common upgrade), I would find that after
>installing the Class D amp, I would then only be using four channels of the
>five channels possible in the SS 705, thereby wasting resource. This does
>not happen when all of your amps are two channel (you can simply sell your
>old sub amp).
>
>MOSFET
>

A bunch of good points there. I put a five-channel PPI amp in my
wife's car a few years ago. With her car, I went the multi-channel
route because space was seriously limited, and I knew that once I got
it installed, she wasn't likely to want to upgrade the components very
often.

For my own systems, I've always wanted the maximum flexibility, and I
like it when each component only does one thing. For instance, I like
my amplifiers to amplify, and that's it. If I want crossovers, bass
boost, filters, equalizers, etcetera, I use separate dedicated
components.

There's one component out there that might change my mind - the
AudioControl DQX. It's essentially a pair of digital 30-band
1/3-octave equalizers, a two-band parametric equalizer, and a 3-way
crossover in one small chassis. For anyone that remembers the old
30-band EQT equalizer and 4XS crossovers, this one box replaces two
EQTs and a 4XS, plus gives you a parametric equalizer.

When it comes to amplifiers, the best of all possible worlds would be
a completely "modular" amplifier. You would buy a skeleton chassis
that has a single power, ground, and turn-on connection. Then, you
add "modules" to expand the amp. You might want two 75-watt modules
for your front components, two 50-watt modules for your rear speakers,
and a 200-watt module for your sub. You could mix, match, and replace
individual amplifier modules, and they'd all receive their power from
the skeleton chassis. Likewise, you could plug crossover modules or
filter modules into the chassis as well.

This would have the benefits of a multi-channel amp (reduced space
requirements and less interconnecting wiring), and also the benefits
of separate components (flexiblity and upgradabililty). The biggest
drawback is that the wiring in the skeleton chassis would have to be
big enough to handle the most powerful amplifier modules, even if you
only have smaller modules installed. Also, this would be an
enthusiast-only type of product, so the market will be pretty limited,
driving up the costs.

In the meantime, I'll stick with several two-channel amps and outboard
signal processors to maximize the flexibility.





--
Scott Gardner

"No man's life, liberty, or property is safe while the legislature is in session." (Judge Gideon J. Tucker, 1866.)"

[Auto]

Great Stuff. Thanks.

Let me expand a little.

I bought the CDA-9833 which is CEA-2006 Compliant. Alpine states the HU
is 25 Watts per channel X 4.

The speakers I have in my car are the stock speakers. The Watt Rating
is unknown at this time.

The Volume knob on the Alpine goes to 35. I can only turn the volume
up to 18 or 20 before the speakers begin to sound distorted.

I will replace my speakers within the next few days. I'm thinking of
buying the Alpine SPR-694A (6"x9") for the Rears; the SPR-174A (6
=BD") for the front doors. These Alpines sounded the best to me.

The rears are rated to be 8-50 watts RMS.

The fronts are rated to be 8-40 watts RMS.

Theoretically, after replacing the stock speakers with the new
speakers, I should be able to turn the volume knob to its' max - 35.
The speakers should not sound distorted. The Circuit City Guy
concurred.

(The Circuit City Guy also said that if I add a 50-Watt Per Channel
Amp, I could turn the volume knob all the way up without distortion.
Which really doesn't make sense considering I'd be exceeding the
RMS for the 6 =BD"'s.)

The wattage of the HU is 25-Watts Per Channel. I'm concerned that
with only 4 speakers, I may later want to add a Sub for a better
overall sound.

If I add a Sub, it'll need an Amp. If I add a sub-amp, my watts will
be out of whack. That is for example, 200 Watts going to the Sub while
only 25 can go to each speaker.

My idea is to get the Multi-Channel amp. It should be engineered to
provide a "Balanced" sound. That is, X Watts per channel
compensated for the Sub Volume. However, if I get the Amp, I may have
to reconsider the speakers because of the RMS. I'd prefer to
understand this stuff a little more before dropping the cash on the new
speakers, only to have to replace them later in the year.


Any of this making sense? Oh, I just want loud, clear audio. I don't
necessarily want to rattle windows when I drive by.

[Auto]

Great Stuff. Thanks.

Let me expand a little.

I bought the CDA-9833 which is CEA-2006 Compliant. Alpine states the HU
is 25 Watts per channel X 4.

The speakers I have in my car are the stock speakers. The Watt Rating
is unknown at this time.

The Volume knob on the Alpine goes to 35. I can only turn the volume
up to 18 or 20 before the speakers begin to sound distorted.

I will replace my speakers within the next few days. I'm thinking of
buying the Alpine SPR-694A (6"x9") for the Rears; the SPR-174A (6
=BD") for the front doors. These Alpines sounded the best to me.

The rears are rated to be 8-50 watts RMS.

The fronts are rated to be 8-40 watts RMS.

Theoretically, after replacing the stock speakers with the new
speakers, I should be able to turn the volume knob to its' max - 35.
The speakers should not sound distorted. The Circuit City Guy
concurred.

(The Circuit City Guy also said that if I add a 50-Watt Per Channel
Amp, I could turn the volume knob all the way up without distortion.
Which really doesn't make sense considering I'd be exceeding the
RMS for the 6 =BD"'s.)

The wattage of the HU is 25-Watts Per Channel. I'm concerned that
with only 4 speakers, I may later want to add a Sub for a better
overall sound.

If I add a Sub, it'll need an Amp. If I add a sub-amp, my watts will
be out of whack. That is for example, 200 Watts going to the Sub while
only 25 can go to each speaker.

My idea is to get the Multi-Channel amp. It should be engineered to
provide a "Balanced" sound. However, if I get the Amp, I may have
to reconsider the speakers because of the RMS. I'd prefer to
understand this stuff a little more before dropping the cash on the new
speakers, only to have to replace them later.


Any of this making sense?

[MZ]

The Circuit City guy is incorrect. The speakers will distort if the output
of the head unit is clipping. This typically occurs well before you reach
max for most types of music.

"Auto" > wrote in message
oups.com...
Great Stuff. Thanks.

Let me expand a little.

I bought the CDA-9833 which is CEA-2006 Compliant. Alpine states the HU
is 25 Watts per channel X 4.

The speakers I have in my car are the stock speakers. The Watt Rating
is unknown at this time.

The Volume knob on the Alpine goes to 35. I can only turn the volume
up to 18 or 20 before the speakers begin to sound distorted.

I will replace my speakers within the next few days. I'm thinking of
buying the Alpine SPR-694A (6"x9") for the Rears; the SPR-174A (6
½") for the front doors. These Alpines sounded the best to me.

The rears are rated to be 8-50 watts RMS.

The fronts are rated to be 8-40 watts RMS.

Theoretically, after replacing the stock speakers with the new
speakers, I should be able to turn the volume knob to its' max - 35.
The speakers should not sound distorted. The Circuit City Guy
concurred.

(The Circuit City Guy also said that if I add a 50-Watt Per Channel
Amp, I could turn the volume knob all the way up without distortion.
Which really doesn't make sense considering I'd be exceeding the
RMS for the 6 ½"'s.)

The wattage of the HU is 25-Watts Per Channel. I'm concerned that
with only 4 speakers, I may later want to add a Sub for a better
overall sound.

If I add a Sub, it'll need an Amp. If I add a sub-amp, my watts will
be out of whack. That is for example, 200 Watts going to the Sub while
only 25 can go to each speaker.

My idea is to get the Multi-Channel amp. It should be engineered to
provide a "Balanced" sound. That is, X Watts per channel
compensated for the Sub Volume. However, if I get the Amp, I may have
to reconsider the speakers because of the RMS. I'd prefer to
understand this stuff a little more before dropping the cash on the new
speakers, only to have to replace them later in the year.


Any of this making sense? Oh, I just want loud, clear audio. I don't
necessarily want to rattle windows when I drive by.

[MOSFET]

You seem to be confused about a few things. First, the volume indicator
(0-35) on your Alpine has really nothing to do with anything. When you turn
it up past 30 or so, the HEAD UNIT will start producing distortion, not your
speakers.

Just because you are getting a sub and sub amp doesn't necessarily mean you
have to get an amp for your other speakers. The amp in your HU is the same
one in mine (a 7863) and it puts out 27 watts per channel RMS. In my last
car, I had this HU driving a pair of Boston 6 X 9's for my rear-fill and
they REALLY cranked! Depending on the efficiency of your new Alpine
speakers and how you have them crossed over (you will need a high-pass
crossover for those speakers once you have a sub installed because they will
no longer need to reproduce low bass), you may find that the Alpine has all
the power you need. Remember, it is bass that requires most power and that
will be handled by the sub.

That being said, an amp is ALWAYS a good idea, however, because even at
lower volumes, amps tend to make speakers sound better (clearer, more
dynamic).

MOSFET



"Auto" > wrote in message
oups.com...
Great Stuff. Thanks.

Let me expand a little.

I bought the CDA-9833 which is CEA-2006 Compliant. Alpine states the HU
is 25 Watts per channel X 4.

The speakers I have in my car are the stock speakers. The Watt Rating
is unknown at this time.

The Volume knob on the Alpine goes to 35. I can only turn the volume
up to 18 or 20 before the speakers begin to sound distorted.

I will replace my speakers within the next few days. I'm thinking of
buying the Alpine SPR-694A (6"x9") for the Rears; the SPR-174A (6
½") for the front doors. These Alpines sounded the best to me.

The rears are rated to be 8-50 watts RMS.

The fronts are rated to be 8-40 watts RMS.

Theoretically, after replacing the stock speakers with the new
speakers, I should be able to turn the volume knob to its' max - 35.
The speakers should not sound distorted. The Circuit City Guy
concurred.

(The Circuit City Guy also said that if I add a 50-Watt Per Channel
Amp, I could turn the volume knob all the way up without distortion.
Which really doesn't make sense considering I'd be exceeding the
RMS for the 6 ½"'s.)

The wattage of the HU is 25-Watts Per Channel. I'm concerned that
with only 4 speakers, I may later want to add a Sub for a better
overall sound.

If I add a Sub, it'll need an Amp. If I add a sub-amp, my watts will
be out of whack. That is for example, 200 Watts going to the Sub while
only 25 can go to each speaker.

My idea is to get the Multi-Channel amp. It should be engineered to
provide a "Balanced" sound. However, if I get the Amp, I may have
to reconsider the speakers because of the RMS. I'd prefer to
understand this stuff a little more before dropping the cash on the new
speakers, only to have to replace them later.


Any of this making sense?

[Auto]

MOSFET wrote:
> You seem to be confused about a few things.

Oh no, I'm not confused at all. I've got a HU that according to the
manufacturer puts out 26 Watts per channel, according to you puts out
27 Watts per channel, yet sounds distorted when I turn it up above 20
on the Volume Scale that maxs at 35.

So the HU starts Clipping at 57% of volume - great.

I'll buy upgraded speakers, one set that can only handle a rated 8-40
watts RMS, only to require an amp later because the HU will still clip
at 20. I'll then over-power the replacment speakers that will then
have to be upgraded a second time.

Pulling teeth out

Thanks.

[[email protected]]

If you want loud get an amp. Forget about how much the hu puts out. Get
a amp thats 75-150 watts per channel. With that you will be able to run
your speakers louder before they distort.

[MZ]

>> You seem to be confused about a few things.
>
> Oh no, I'm not confused at all. I've got a HU that according to the
> manufacturer puts out 26 Watts per channel, according to you puts out
> 27 Watts per channel, yet sounds distorted when I turn it up above 20
> on the Volume Scale that maxs at 35.
>
> So the HU starts Clipping at 57% of volume - great.

There's nothing wrong with this. In fact, this is a good thing. This is
how it's supposed to be. When you listen to quieter tracks, you need to be
able to achieve max output with these tracks. If your head unit was set so
that it achieved max volume when your volume knob was all the way up with,
say, a -3dB track, you couldn't get max output if you listened to a -6dB
recording. That's why they do it this way. You'll still get your "27
watts" out.

> I'll buy upgraded speakers, one set that can only handle a rated 8-40
> watts RMS, only to require an amp later because the HU will still clip
> at 20. I'll then over-power the replacment speakers that will then
> have to be upgraded a second time.

Frankly, 27 watts isn't that much. That's your problem, not the volume
knob.

[Auto]

MZ wrote:
>
>
> Frankly, 27 watts isn't that much. That's your problem, not the
volume
> knob.


Good point on the DB's.

OK. All posts point to an Amp.

How many Watts should an Amp be capable of producing Vs. Max Speaker
RMS? Is there a formula?

Also, If I get an Amp, then the Amp will be what powers the speakers.
At that point, the HU is only going to be used for Sound Adjustments.

Do Amps have a particular sound? For example, my house stereo is a
Kenwood. It has a different distinct sound Vs. a Yamaha or Sony (all
in their respective "Flat" Positions).

Also, if the speakers are rated 8-40 Watts RMS, will the stereo have to
be turned up loud before the speakers will drive? OR can low-moderate
volumes be produced with a nudge of the volume knob.

Thanks a lot fellas.

[[email protected]]

A watt is a watt is a watt.