4 Ohm vs. 8 Ohm Question

[Alan S]

I am new to the world of car audio and I have a few questions. The system I
am asking about is in a sailboat so energy efficiency is very important. I
have 2 deep cycle batteries and the auxiliary power (the diesel engine) will
recharge them but while I am sailing the batteries are the only source of
power for a system that is often on for several hours listening to CD's and
satellite radio.

I had originally put some Bose desktop speakers in the cabin thinking that
car systems were 8 ohm. The speakers sound really good but I have now come
to understand that I am only getting half of the power to them because the
output of the head unit is 4 ohms, not 8 ohm.

Here is the current layout:

I have a Sony Xplode head unit. I am not sure of the model but it is 52 X 4
and I think it is 17 watts RMS. This head unit is powering two 6 inch 4 ohm
speakers in the cockpit, and two 8 ohm shelf speakers in the cabin. There is
one line out from the head unit to a 220 watt amp that I am only using one
side of to power a 10 inch sub-woofer in the cabin. The amp is connected
directly to the batteries with 10 gauge wire.

My questions are:

Is there any reason that I should replace the 8 ohm shelf speakers with 4
ohm 6 X 9 speakers in sealed boxes? Would I lose sound quality?

If I continue to use the 8 ohm speakers will it be more power efficient?

Are there problems that arise from using both 4 and 8 ohm speakers wired to
a 4 ohm output head unit?

Sound quality at moderate volumes with efficient power usage is my goal.

Thanks for your time,

- A -

[mfreak]

Your setup isn't hurting anything.. No problems running 2 4 ohm and 2
8 ohm speakers. The 8 ohm speakers are drawing less power than they
would if they were 4 ohms. If you replaced the 8 ohm speakers with 4
ohm ones, then they'd draw more rms from your HU, it'd be louder, and
your boat's elec. system would have to come up with (slightly) more
current to push it.

[D.Kreft]

On Oct 30, 12:23 pm, "Alan S" > wrote:

> Is there any reason that I should replace the 8 ohm shelf speakers with 4
> ohm 6 X 9 speakers in sealed boxes? Would I lose sound quality?

I'd say you're more likely to lose SQ by swithing to 6x9's in boxes.
Six-by-nines are intended to work in a free-air situation (technically
speaking, "in an enclosure whose volume is greater than the Vas of the
loudspeaker), so you'd have to build a pretty big box to get them to
play the way they're supposed to. Even if you didn't mind doing that,
without knowing which 6x9's you're thinking of and how your current
home speakers sound, it's going to be pretty difficult to tell how much
better or worse the 6x9's would sound.

> If I continue to use the 8 ohm speakers will it be more power efficient?

The depends upon how you're out to define efficiency. The 4-Ohm
speakers may be a bit louder given that current through them would be
double that of the home speakers, but as far as true efficiency (how
much sound energy is created per watt of electrical energy), that's not
terribly straightforward to determine.

> Are there problems that arise from using both 4 and 8 ohm speakers wired to
> a 4 ohm output head unit?

No. Given two speakers that are "identical" in all respects save their
respective impedances, the 4-Ohm speaker will be 3dB SPL louder than
the 8-Ohm speaker. That's not a terribly large difference--3dB SPL is
generally considered to be the threshold of the human ear's ability to
detect loudness changes.

The only thing you have to concern yourself with is not going *below*
the rated impedance of the device to which you are attaching speakers.
If you were to put a 4-Ohm and an 8-Ohm speaker on the same channel
with both drivers wired in parallel (+ to +, - to -), *then* you'd have
an impedance of 2.66 Ohms, which is below the 4-Ohm rating of the head
unit--and that makes it likely that you'll let the "magic smoke" out of
your head unit.

> Sound quality at moderate volumes with efficient power usage is my goal.

I wouldn't worry about it. Your biggest power consumer is going to be
the amplifier powering your subwoofer. Focusing on the head unit and
the impedance of the speakers attached to it is kinda like trying to
make your car go faster by removing an un-aerodynamic hood
ornament--percentage-wise it's not even making a dent compared to your
amp.

-dan

[brianlanning]

Alan S wrote:
> I had originally put some Bose desktop speakers in the cabin thinking that
> car systems were 8 ohm. The speakers sound really good but I have now come
> to understand that I am only getting half of the power to them because the
> output of the head unit is 4 ohms, not 8 ohm.

The speakers are 4 or 8 ohms. Amplifier output (like the one in the
head unit) aren't rated in ohms. They're rated in watts, either
peek/max or RMS (an average). The ratings you find for car amplifiers
are generally rated at 4 ohm loads. If you attach an 8 ohm speaker to
one of the channels, you'll get half of the power output. The amp will
run cooler and draw less power, and probably sound better. But it
won't get as loud.


> Here is the current layout:
> I have a Sony Xplode head unit. I am not sure of the model but it is 52 X 4
> and I think it is 17 watts RMS.

52 sounds like a marketing number, 17 sounds right.

>This head unit is powering two 6 inch 4 ohm
> speakers in the cockpit, and two 8 ohm shelf speakers in the cabin. There is
> one line out from the head unit to a 220 watt amp that I am only using one
> side of to power a 10 inch sub-woofer in the cabin. The amp is connected
> directly to the batteries with 10 gauge wire.
>
> My questions are:
>
> Is there any reason that I should replace the 8 ohm shelf speakers with 4
> ohm 6 X 9 speakers in sealed boxes? Would I lose sound quality?

It depends on both sets of speakers. It's hard to say. In a car you
probably wouldn't be able to tell the difference, except that the 4 ohm
speakers would probably be noticably louder. In a quiet boat without
the engine running, you might be able to hear a sound quality
difference, or maybe not.


> If I continue to use the 8 ohm speakers will it be more power efficient?

in theory, it should draw less power making the batteries last longer.
Those two channels would be drawing half the current. But with the sub
amp, you might not notice the difference.

> Are there problems that arise from using both 4 and 8 ohm speakers wired to
> a 4 ohm output head unit?

it's ok. they're separate channels. If you wired them in series or
parallel to the same channel, you might get strange behavior depending
on the resulting load.

> Sound quality at moderate volumes with efficient power usage is my goal.

If you're happy with the sound quality, leave it alone. If you want it
to get a bit louder, but still sound ok, the 6x9s are a good way to go.
You could also adjust the fader to the back and turn up the head unit
a little more to dive the 8 ohm speakers harder and the 4 ohm speakers
less. This may affect the sound quality from the head unit though.

You might get better sound quality if you replace the head unit amp
with another outboard amp like the one you're using for the sub. You
could pick up a 15x4 or 30x4 rms or two 2 channel amps. If you do it
right, for the price of the 6x9s and the speaker boxes, you could get
an amp for the 8 ohm speakers and adjust the gain to where you want it.

brian

[Alan S]

"D.Kreft" > wrote in message
oups.com...
> On Oct 30, 12:23 pm, "Alan S" > wrote:
>
>> Is there any reason that I should replace the 8 ohm shelf speakers with 4
>> ohm 6 X 9 speakers in sealed boxes? Would I lose sound quality?
>
> I'd say you're more likely to lose SQ by swithing to 6x9's in boxes.
> Six-by-nines are intended to work in a free-air situation (technically
> speaking, "in an enclosure whose volume is greater than the Vas of the
> loudspeaker), so you'd have to build a pretty big box to get them to
> play the way they're supposed to. Even if you didn't mind doing that,
> without knowing which 6x9's you're thinking of and how your current
> home speakers sound, it's going to be pretty difficult to tell how much
> better or worse the 6x9's would sound.
>
>> If I continue to use the 8 ohm speakers will it be more power efficient?
>
> The depends upon how you're out to define efficiency. The 4-Ohm
> speakers may be a bit louder given that current through them would be
> double that of the home speakers, but as far as true efficiency (how
> much sound energy is created per watt of electrical energy), that's not
> terribly straightforward to determine.
>
>> Are there problems that arise from using both 4 and 8 ohm speakers wired
>> to
>> a 4 ohm output head unit?
>
> No. Given two speakers that are "identical" in all respects save their
> respective impedances, the 4-Ohm speaker will be 3dB SPL louder than
> the 8-Ohm speaker. That's not a terribly large difference--3dB SPL is
> generally considered to be the threshold of the human ear's ability to
> detect loudness changes.
>
> The only thing you have to concern yourself with is not going *below*
> the rated impedance of the device to which you are attaching speakers.
> If you were to put a 4-Ohm and an 8-Ohm speaker on the same channel
> with both drivers wired in parallel (+ to +, - to -), *then* you'd have
> an impedance of 2.66 Ohms, which is below the 4-Ohm rating of the head
> unit--and that makes it likely that you'll let the "magic smoke" out of
> your head unit.
>
>> Sound quality at moderate volumes with efficient power usage is my goal.
>
> I wouldn't worry about it. Your biggest power consumer is going to be
> the amplifier powering your subwoofer. Focusing on the head unit and
> the impedance of the speakers attached to it is kinda like trying to
> make your car go faster by removing an un-aerodynamic hood
> ornament--percentage-wise it's not even making a dent compared to your
> amp.
>
> -dan
>
Thank you for the information. I did not know about the 6X9's and the sealed
boxes, and I learned other things from your response as well. As it is, I
have decided to leave the 8 ohm speakers and actually get another pair of
Bose and mount them up by the ceiling for my mids/highs and run them off of
the other channel on the amp. I was talking with someone in IRC that said he
used deep cycle batteries with his system and he could run it all day with
no problems at all, and indeed, I did listen to music for several hours on
Sunday with one battery with no noticeable loss of power. I just wanted to
be sure about it.

[GregS]

In article >, "Alan S" > wrote:
>
>"D.Kreft" > wrote in message
oups.com...
>> On Oct 30, 12:23 pm, "Alan S" > wrote:
>>
>>> Is there any reason that I should replace the 8 ohm shelf speakers with 4
>>> ohm 6 X 9 speakers in sealed boxes? Would I lose sound quality?
>>
>> I'd say you're more likely to lose SQ by swithing to 6x9's in boxes.
>> Six-by-nines are intended to work in a free-air situation (technically
>> speaking, "in an enclosure whose volume is greater than the Vas of the
>> loudspeaker), so you'd have to build a pretty big box to get them to
>> play the way they're supposed to. Even if you didn't mind doing that,
>> without knowing which 6x9's you're thinking of and how your current
>> home speakers sound, it's going to be pretty difficult to tell how much
>> better or worse the 6x9's would sound.
>>
>>> If I continue to use the 8 ohm speakers will it be more power efficient?
>>
>> The depends upon how you're out to define efficiency. The 4-Ohm
>> speakers may be a bit louder given that current through them would be
>> double that of the home speakers, but as far as true efficiency (how
>> much sound energy is created per watt of electrical energy), that's not
>> terribly straightforward to determine.
>>
>>> Are there problems that arise from using both 4 and 8 ohm speakers wired
>>> to
>>> a 4 ohm output head unit?
>>
>> No. Given two speakers that are "identical" in all respects save their
>> respective impedances, the 4-Ohm speaker will be 3dB SPL louder than
>> the 8-Ohm speaker. That's not a terribly large difference--3dB SPL is
>> generally considered to be the threshold of the human ear's ability to
>> detect loudness changes.
>>
>> The only thing you have to concern yourself with is not going *below*
>> the rated impedance of the device to which you are attaching speakers.
>> If you were to put a 4-Ohm and an 8-Ohm speaker on the same channel
>> with both drivers wired in parallel (+ to +, - to -), *then* you'd have
>> an impedance of 2.66 Ohms, which is below the 4-Ohm rating of the head
>> unit--and that makes it likely that you'll let the "magic smoke" out of
>> your head unit.
>>
>>> Sound quality at moderate volumes with efficient power usage is my goal.
>>
>> I wouldn't worry about it. Your biggest power consumer is going to be
>> the amplifier powering your subwoofer. Focusing on the head unit and
>> the impedance of the speakers attached to it is kinda like trying to
>> make your car go faster by removing an un-aerodynamic hood
>> ornament--percentage-wise it's not even making a dent compared to your
>> amp.
>>
>> -dan
>>
>Thank you for the information. I did not know about the 6X9's and the sealed
>boxes, and I learned other things from your response as well. As it is, I
>have decided to leave the 8 ohm speakers and actually get another pair of
>Bose and mount them up by the ceiling for my mids/highs and run them off of
>the other channel on the amp. I was talking with someone in IRC that said he
>used deep cycle batteries with his system and he could run it all day with
>no problems at all, and indeed, I did listen to music for several hours on
>Sunday with one battery with no noticeable loss of power. I just wanted to
>be sure about it.

The only thing you will get is distortion with when the battery tuckers out.
By then, its allready damaged. Some of the life will permanately be
sucked away. There are devices which remove the battery when its
close to expiring the charge.

Bose, 6X9, Perhaps you should choose the 6X9's.

greg

[Alan S]

"brianlanning" > wrote in message
ups.com...
> Alan S wrote:
>> I had originally put some Bose desktop speakers in the cabin thinking
>> that
>> car systems were 8 ohm. The speakers sound really good but I have now
>> come
>> to understand that I am only getting half of the power to them because
>> the
>> output of the head unit is 4 ohms, not 8 ohm.
>
> The speakers are 4 or 8 ohms. Amplifier output (like the one in the
> head unit) aren't rated in ohms. They're rated in watts, either
> peek/max or RMS (an average). The ratings you find for car amplifiers
> are generally rated at 4 ohm loads. If you attach an 8 ohm speaker to
> one of the channels, you'll get half of the power output. The amp will
> run cooler and draw less power, and probably sound better. But it
> won't get as loud.
>
>
>> Here is the current layout:
>> I have a Sony Xplode head unit. I am not sure of the model but it is 52 X
>> 4
>> and I think it is 17 watts RMS.
>
> 52 sounds like a marketing number, 17 sounds right.


Do they make head units that put out a decent amount of wattage? or is it
unnecessary with an amp?


>
>>This head unit is powering two 6 inch 4 ohm
>> speakers in the cockpit, and two 8 ohm shelf speakers in the cabin. There
>> is
>> one line out from the head unit to a 220 watt amp that I am only using
>> one
>> side of to power a 10 inch sub-woofer in the cabin. The amp is connected
>> directly to the batteries with 10 gauge wire.
>>
>> My questions are:
>>
>> Is there any reason that I should replace the 8 ohm shelf speakers with 4
>> ohm 6 X 9 speakers in sealed boxes? Would I lose sound quality?
>
> It depends on both sets of speakers. It's hard to say. In a car you
> probably wouldn't be able to tell the difference, except that the 4 ohm
> speakers would probably be noticably louder. In a quiet boat without
> the engine running, you might be able to hear a sound quality
> difference, or maybe not.
>
>
>> If I continue to use the 8 ohm speakers will it be more power efficient?
>
> in theory, it should draw less power making the batteries last longer.
> Those two channels would be drawing half the current. But with the sub
> amp, you might not notice the difference.
>
>> Are there problems that arise from using both 4 and 8 ohm speakers wired
>> to
>> a 4 ohm output head unit?
>
> it's ok. they're separate channels. If you wired them in series or
> parallel to the same channel, you might get strange behavior depending
> on the resulting load.
>
>> Sound quality at moderate volumes with efficient power usage is my goal.
>
> If you're happy with the sound quality, leave it alone. If you want it
> to get a bit louder, but still sound ok, the 6x9s are a good way to go.
> You could also adjust the fader to the back and turn up the head unit
> a little more to dive the 8 ohm speakers harder and the 4 ohm speakers
> less. This may affect the sound quality from the head unit though.


I have been doing that unknowingly for the whole time it has been hooked up.
I just figured the front channel was a little off from the other one. It is
good to know why I have been doing that. The head unit actually sounds ok. I
don't like the controls on it and I replaced it with a Clarion unit thinking
that newer technology would probably sound better. It didn't. I put the Sony
back in and took the Clarion back to the store for a refund. I am keeping my
eye out for a kick ass head unit. Any recommendations?


> You might get better sound quality if you replace the head unit amp
> with another outboard amp like the one you're using for the sub. You
> could pick up a 15x4 or 30x4 rms or two 2 channel amps. If you do it
> right, for the price of the 6x9s and the speaker boxes, you could get
> an amp for the 8 ohm speakers and adjust the gain to where you want it.
>


Since I don't listen music at really loud levels much any more (been there -
done lots of it) I am mostly after sound quality. It's not like I have a
turntable on the boat or anything and where it's true that you will only get
so far with 44.1 kHZ at 16 bit, still, I want my CD's to sound as good as
possible. The amp I have the sub-woofer on has a second channel, I am going
to use that for another set of Bose speakers I can mount up by the ceiling
for my mids/highs. I am very pleased to know that this whole thing won't be
too much of a power draw. It was looking like it was just going to kill the
whole thing until I wired the amp directly to the power source, that made a
huge difference. The lights were dimming and dancing with the sound output,
that's not happening now.


> brian
>

[Alan S]

"GregS" > wrote in message
...
> In article >, "Alan S"
> > wrote:
>>
>>"D.Kreft" > wrote in message
oups.com...
>>> On Oct 30, 12:23 pm, "Alan S" > wrote:
>>>
>>>> Is there any reason that I should replace the 8 ohm shelf speakers with
>>>> 4
>>>> ohm 6 X 9 speakers in sealed boxes? Would I lose sound quality?
>>>
>>> I'd say you're more likely to lose SQ by swithing to 6x9's in boxes.
>>> Six-by-nines are intended to work in a free-air situation (technically
>>> speaking, "in an enclosure whose volume is greater than the Vas of the
>>> loudspeaker), so you'd have to build a pretty big box to get them to
>>> play the way they're supposed to. Even if you didn't mind doing that,
>>> without knowing which 6x9's you're thinking of and how your current
>>> home speakers sound, it's going to be pretty difficult to tell how much
>>> better or worse the 6x9's would sound.
>>>
>>>> If I continue to use the 8 ohm speakers will it be more power
>>>> efficient?
>>>
>>> The depends upon how you're out to define efficiency. The 4-Ohm
>>> speakers may be a bit louder given that current through them would be
>>> double that of the home speakers, but as far as true efficiency (how
>>> much sound energy is created per watt of electrical energy), that's not
>>> terribly straightforward to determine.
>>>
>>>> Are there problems that arise from using both 4 and 8 ohm speakers
>>>> wired
>>>> to
>>>> a 4 ohm output head unit?
>>>
>>> No. Given two speakers that are "identical" in all respects save their
>>> respective impedances, the 4-Ohm speaker will be 3dB SPL louder than
>>> the 8-Ohm speaker. That's not a terribly large difference--3dB SPL is
>>> generally considered to be the threshold of the human ear's ability to
>>> detect loudness changes.
>>>
>>> The only thing you have to concern yourself with is not going *below*
>>> the rated impedance of the device to which you are attaching speakers.
>>> If you were to put a 4-Ohm and an 8-Ohm speaker on the same channel
>>> with both drivers wired in parallel (+ to +, - to -), *then* you'd have
>>> an impedance of 2.66 Ohms, which is below the 4-Ohm rating of the head
>>> unit--and that makes it likely that you'll let the "magic smoke" out of
>>> your head unit.
>>>
>>>> Sound quality at moderate volumes with efficient power usage is my
>>>> goal.
>>>
>>> I wouldn't worry about it. Your biggest power consumer is going to be
>>> the amplifier powering your subwoofer. Focusing on the head unit and
>>> the impedance of the speakers attached to it is kinda like trying to
>>> make your car go faster by removing an un-aerodynamic hood
>>> ornament--percentage-wise it's not even making a dent compared to your
>>> amp.
>>>
>>> -dan
>>>
>>Thank you for the information. I did not know about the 6X9's and the
>>sealed
>>boxes, and I learned other things from your response as well. As it is, I
>>have decided to leave the 8 ohm speakers and actually get another pair of
>>Bose and mount them up by the ceiling for my mids/highs and run them off
>>of
>>the other channel on the amp. I was talking with someone in IRC that said
>>he
>>used deep cycle batteries with his system and he could run it all day with
>>no problems at all, and indeed, I did listen to music for several hours on
>>Sunday with one battery with no noticeable loss of power. I just wanted to
>>be sure about it.
>
> The only thing you will get is distortion with when the battery tuckers
> out.
> By then, its allready damaged. Some of the life will permanately be
> sucked away. There are devices which remove the battery when its
> close to expiring the charge.
>
> Bose, 6X9, Perhaps you should choose the 6X9's.

Why would you suggest that? Better sound, or maybe you are not a Bose fan?
The only issue I could see if I opted for the 6X9's is that I would have to
make some kind of mounting boxes for them. Is there a way to port the boxes
so they don't dampen the sound? The advantage to the Bose is that they are
aready enclosed and would be easier to mount. These speakers would be
mounted high so I will probably have them back in the mix anyway, which ones
you would use?

> greg
>

[GregS]

In article >, "Alan S" > wrote:
>
>"GregS" > wrote in message
...
>> In article >, "Alan S"
>> > wrote:
>>>
>>>"D.Kreft" > wrote in message
oups.com...
>>>> On Oct 30, 12:23 pm, "Alan S" > wrote:
>>>>
>>>>> Is there any reason that I should replace the 8 ohm shelf speakers with
>>>>> 4
>>>>> ohm 6 X 9 speakers in sealed boxes? Would I lose sound quality?
>>>>
>>>> I'd say you're more likely to lose SQ by swithing to 6x9's in boxes.
>>>> Six-by-nines are intended to work in a free-air situation (technically
>>>> speaking, "in an enclosure whose volume is greater than the Vas of the
>>>> loudspeaker), so you'd have to build a pretty big box to get them to
>>>> play the way they're supposed to. Even if you didn't mind doing that,
>>>> without knowing which 6x9's you're thinking of and how your current
>>>> home speakers sound, it's going to be pretty difficult to tell how much
>>>> better or worse the 6x9's would sound.
>>>>
>>>>> If I continue to use the 8 ohm speakers will it be more power
>>>>> efficient?
>>>>
>>>> The depends upon how you're out to define efficiency. The 4-Ohm
>>>> speakers may be a bit louder given that current through them would be
>>>> double that of the home speakers, but as far as true efficiency (how
>>>> much sound energy is created per watt of electrical energy), that's not
>>>> terribly straightforward to determine.
>>>>
>>>>> Are there problems that arise from using both 4 and 8 ohm speakers
>>>>> wired
>>>>> to
>>>>> a 4 ohm output head unit?
>>>>
>>>> No. Given two speakers that are "identical" in all respects save their
>>>> respective impedances, the 4-Ohm speaker will be 3dB SPL louder than
>>>> the 8-Ohm speaker. That's not a terribly large difference--3dB SPL is
>>>> generally considered to be the threshold of the human ear's ability to
>>>> detect loudness changes.
>>>>
>>>> The only thing you have to concern yourself with is not going *below*
>>>> the rated impedance of the device to which you are attaching speakers.
>>>> If you were to put a 4-Ohm and an 8-Ohm speaker on the same channel
>>>> with both drivers wired in parallel (+ to +, - to -), *then* you'd have
>>>> an impedance of 2.66 Ohms, which is below the 4-Ohm rating of the head
>>>> unit--and that makes it likely that you'll let the "magic smoke" out of
>>>> your head unit.
>>>>
>>>>> Sound quality at moderate volumes with efficient power usage is my
>>>>> goal.
>>>>
>>>> I wouldn't worry about it. Your biggest power consumer is going to be
>>>> the amplifier powering your subwoofer. Focusing on the head unit and
>>>> the impedance of the speakers attached to it is kinda like trying to
>>>> make your car go faster by removing an un-aerodynamic hood
>>>> ornament--percentage-wise it's not even making a dent compared to your
>>>> amp.
>>>>
>>>> -dan
>>>>
>>>Thank you for the information. I did not know about the 6X9's and the
>>>sealed
>>>boxes, and I learned other things from your response as well. As it is, I
>>>have decided to leave the 8 ohm speakers and actually get another pair of
>>>Bose and mount them up by the ceiling for my mids/highs and run them off
>>>of
>>>the other channel on the amp. I was talking with someone in IRC that said
>>>he
>>>used deep cycle batteries with his system and he could run it all day with
>>>no problems at all, and indeed, I did listen to music for several hours on
>>>Sunday with one battery with no noticeable loss of power. I just wanted to
>>>be sure about it.
>>
>> The only thing you will get is distortion with when the battery tuckers
>> out.
>> By then, its allready damaged. Some of the life will permanately be
>> sucked away. There are devices which remove the battery when its
>> close to expiring the charge.
>>
>> Bose, 6X9, Perhaps you should choose the 6X9's.
>
>Why would you suggest that? Better sound, or maybe you are not a Bose fan?
>The only issue I could see if I opted for the 6X9's is that I would have to
>make some kind of mounting boxes for them. Is there a way to port the boxes
>so they don't dampen the sound? The advantage to the Bose is that they are
>aready enclosed and would be easier to mount. These speakers would be
>mounted high so I will probably have them back in the mix anyway, which ones
>you would use?

I don't know what Bose speakers you have or suggest. Bose is highly criticized
here on the Internet, if you do any Google Groups looking around, you will see.
The trouble with most home boxes in the car, is their efficiency is
low. I tried using some Radio Shack Minimus's once. Just no efficiency at all.
If you like the sound of the Bose's, go for it.

greg

[brianlanning]

Alan S wrote:
> Do they make head units that put out a decent amount of wattage? or is it
> unnecessary with an amp?

The amp in your head unit is just another amp. The problem is that
it's small, cheap, and in a bad location. You want an amp to have a
good power supply and a large heat sink. Most head unit amps have a
half-hearted attempt at heat sinks on the back of the head unit or no
heat sink at all. I've heard of some wth fans. The problem is that
the air flow behind the head unit is usually terrible. There's also a
limit to how much current you can pull from the wire that powers the
factory radio. This limits head unit power output as well.

If you get a separate outboard amp for your speakers, you can just stop
using the one in the head unit. You would attach it just like the sub
amp to one of the other sets of RCA connectors.


> I have been doing that unknowingly for the whole time it has been hooked up.
> I just figured the front channel was a little off from the other one. It is
> good to know why I have been doing that. The head unit actually sounds ok. I
> don't like the controls on it and I replaced it with a Clarion unit thinking
> that newer technology would probably sound better. It didn't. I put the Sony
> back in and took the Clarion back to the store for a refund. I am keeping my
> eye out for a kick ass head unit. Any recommendations?

I'm not really up to date on that. I just bought a relatively
inexpensive apline head unit. I bought it mainly for the ipod
interface. I've had good experiences with alpine and sony. I'm sure
the clarion would have been fine also. The best thing to do is shop
based on features and the inteface rather than watts. Most of them
will sound fairly good.


> Since I don't listen music at really loud levels much any more (been there -
> done lots of it) I am mostly after sound quality. It's not like I have a
> turntable on the boat or anything and where it's true that you will only get
> so far with 44.1 kHZ at 16 bit, still, I want my CD's to sound as good as
> possible. The amp I have the sub-woofer on has a second channel, I am going
> to use that for another set of Bose speakers I can mount up by the ceiling
> for my mids/highs.

Be careful with that. If they're 8 ohm speakers, you can wire a pair
in parallel and drive them just fine on one channel. If they're 4 ohm
speakers, you'll have to make sure that your amp is 2-ohm stable with
the same setup.

Another thing, your head unit could have one, two, or three pairs of
RCA outputs. If you have a dedicated sub RCA output, then chances are
that the head unit is filtering out the high frequency component of the
signal before sending it to your amp. You could turn this off in the
head unit though. It's also possible that you're using a full
frequency RCA output for your sub amp. In that case, it's possible
that your amp is filtering out the highs before sending the signal to
the subs. And it's possible that you're sending a full range signal to
your subs (this is bad). If you hook up those extra speakers to the
other channel, make sure they're the higher frequencies, or they'll
sound wrong.

>I am very pleased to know that this whole thing won't be
> too much of a power draw. It was looking like it was just going to kill the
> whole thing until I wired the amp directly to the power source, that made a
> huge difference. The lights were dimming and dancing with the sound output,
> that's not happening now.

Make sure you put an inline fuse on any amp's power wire as close to
the battery as possible. If you don't and there's a short, you could
burn the boat down.

brian

[Alan S]

"brianlanning" > wrote in message
ups.com...
> Alan S wrote:
>> Do they make head units that put out a decent amount of wattage? or is it
>> unnecessary with an amp?
>
> The amp in your head unit is just another amp. The problem is that
> it's small, cheap, and in a bad location. You want an amp to have a
> good power supply and a large heat sink. Most head unit amps have a
> half-hearted attempt at heat sinks on the back of the head unit or no
> heat sink at all. I've heard of some wth fans. The problem is that
> the air flow behind the head unit is usually terrible. There's also a
> limit to how much current you can pull from the wire that powers the
> factory radio. This limits head unit power output as well.
>
> If you get a separate outboard amp for your speakers, you can just stop
> using the one in the head unit. You would attach it just like the sub
> amp to one of the other sets of RCA connectors.
>
>
>> I have been doing that unknowingly for the whole time it has been hooked
>> up.
>> I just figured the front channel was a little off from the other one. It
>> is
>> good to know why I have been doing that. The head unit actually sounds
>> ok. I
>> don't like the controls on it and I replaced it with a Clarion unit
>> thinking
>> that newer technology would probably sound better. It didn't. I put the
>> Sony
>> back in and took the Clarion back to the store for a refund. I am keeping
>> my
>> eye out for a kick ass head unit. Any recommendations?
>
> I'm not really up to date on that. I just bought a relatively
> inexpensive apline head unit. I bought it mainly for the ipod
> interface. I've had good experiences with alpine and sony. I'm sure
> the clarion would have been fine also. The best thing to do is shop
> based on features and the inteface rather than watts. Most of them
> will sound fairly good.
>
>
>> Since I don't listen music at really loud levels much any more (been
>> there -
>> done lots of it) I am mostly after sound quality. It's not like I have a
>> turntable on the boat or anything and where it's true that you will only
>> get
>> so far with 44.1 kHZ at 16 bit, still, I want my CD's to sound as good as
>> possible. The amp I have the sub-woofer on has a second channel, I am
>> going
>> to use that for another set of Bose speakers I can mount up by the
>> ceiling
>> for my mids/highs.
>
> Be careful with that. If they're 8 ohm speakers, you can wire a pair
> in parallel and drive them just fine on one channel. If they're 4 ohm
> speakers, you'll have to make sure that your amp is 2-ohm stable with
> the same setup.
>
> Another thing, your head unit could have one, two, or three pairs of
> RCA outputs. If you have a dedicated sub RCA output, then chances are
> that the head unit is filtering out the high frequency component of the
> signal before sending it to your amp. You could turn this off in the
> head unit though. It's also possible that you're using a full
> frequency RCA output for your sub amp. In that case, it's possible
> that your amp is filtering out the highs before sending the signal to
> the subs. And it's possible that you're sending a full range signal to
> your subs (this is bad). If you hook up those extra speakers to the
> other channel, make sure they're the higher frequencies, or they'll
> sound wrong.


Why is a full range signal to a sub a bad thing?


>>I am very pleased to know that this whole thing won't be
>> too much of a power draw. It was looking like it was just going to kill
>> the
>> whole thing until I wired the amp directly to the power source, that made
>> a
>> huge difference. The lights were dimming and dancing with the sound
>> output,
>> that's not happening now.
>
> Make sure you put an inline fuse on any amp's power wire as close to
> the battery as possible. If you don't and there's a short, you could
> burn the boat down.
>
> brian
>

[D.Kreft]

On Oct 31, 9:41 am, "Alan S" > wrote:

> Why is a full range signal to a sub a bad thing?

For several reasons:

1. Subwoofers are typically optimized for playing only low frequencies
(i.e. < 100Hz, although the optimal range varies wildly from
manufacturer to manufacturer). So playing them "full-range" without a
crossover will typically result in really "muddy"-sounding bass.

2. The higher the frequency a speaker of any size plays, the easier it
is to locate. Subwoofers are typically located either in the rear of
the vehicle or otherwise tucked into some corner somewhere out of
sight. If a sub is allowed to play "full range", it'll be easier to
locate it and thus it will drag your soundstage from the front of the
car/boat/living room to wherever it is.

3. The higher the frequency, the easier it is for the human ear to
detect distortion. If you're like 90% of the population, you try to get
the absolute most out of your bass amp, and if you're running
full-range, you lose some of that ability. Using a good electronic
crossover with a well-chosen crossover frequency will allow you to
"krunk it up" a bit more with no discernable degredation of sound
quality.

4. Asking a sub to play full range is about as silly as trying to take
a Hummer (the H1, mind you--not the puny H3) to Rome and driving on its
narrow streets, expecting not to annihilate innocent bystanders and
their vehicles--it just wasn't made for that.

-dan

[brianlanning]

D.Kreft wrote:
> On Oct 31, 9:41 am, "Alan S" > wrote:
>
> > Why is a full range signal to a sub a bad thing?
>
> For several reasons:

What he said. It won't hurt the speaker. It will just sound bad.

brian

[GregS]

In article om>, "brianlanning" > wrote:
>D.Kreft wrote:
>> On Oct 31, 9:41 am, "Alan S" > wrote:
>>
>> > Why is a full range signal to a sub a bad thing?
>>
>> For several reasons:
>
>What he said. It won't hurt the speaker. It will just sound bad.

It does create more heat dissapation. Since the usuall Z goes up
higher in frequency it limits the power, still the amount of band above the uaual 100 Hz
is quite a bit.

greg

[D.Kreft]

On Oct 31, 11:21 am, (GregS) wrote:

>What he said. It won't hurt the speaker. It will just sound bad.It does create more heat dissapation. Since the usuall Z goes up
> higher in frequency it limits the power, still the amount of band above the uaual 100 Hz
> is quite a bit.

While true, I think that all things considered this isn't really an
issue to worry about.

-dan