How much watts is it?

 

Technically the amp is 4x20 (or 25)watts into a four ohm load. However the factory speakers are a 1 ohm load. Theoretically this is the equivalent of adding about 6db output, which is the equivalent of doubling your output twice This would be equivalent output wise of a 4 x 80 watt (or 100) if were going to compare it to what you have at home.
In any case, what makes an amplifier perform well is its current output across the audio band. A good analogy is torque in an engine. If we had 260 hp with 232 torque from 0 - 7500 rpm, it would be a great amp. 500 hp with little torque is useless. This is much like car amps. You can buy a 200 watt amp for 39.00 or you can spend over 1000.00. Obviously there is a difference.
Sorry I am rambling but I've been doing high end car audio since 1979.

 

oops I meant great 'engine' back there...

 

BTW I am installing a 4 x 325 watt amp tomorrow , puchased in 1984 for 1600.00. More details will be available...

 

I think you might be wrong on the impedance (not sure if I spelled that right). I emailed Bose a while back and this is what they had to say:

The CL has the following content

6.5" woofer front doors (2 ohm)

2" twiddler front door (4 ohm)

6x9 speaker rear (2 ohm)

Thank you for choosing Bose Corporation.

I'm no expert or anything but I thought I would give any help that I could.

 

Info I posted was measured on 1998 3.0CL factory system using a rockford fosgate impedence meter. Using a standard ohmeter is not as accurate because it give an average impedence or resistance. The fosgate diagnostic tool and the impedence will vary with frequency. The actual impedence will jump from around 1.1 to as much as 50 ohms at some of the frequencies from 50 hz to around 22k.

 

LOL -- "2" twiddler front door" -- you got that right--and that's a fact, Jack! There's no way you could call that Blowz component a tweeter! As for the other lo-fi Bloze components, their lack of fidelity is superseded only by the inability of the anemic 2-ohm impedance Bloze power amp to deliver clean, usable power.

Do yourselves a favor--replace the speakers and the amp. (NAVI guys, keep the factory head unit!)

[ 08-13-2001: Message edited by: technoid ]

 

I think you are correct. Bose does use low impedance speakers in some model cars to be able to not have to use a "power inverter" to get the high voltage necessary to get a ton of power into a 4 or 8 ohm speaker.

In my 92 Maxima SE, they used "bridged" amps and 1-ohm speakers.

To get the power output of an amplifier, you take the RMS voltage and square it, then divide by the speaker's impedance:

Home stereo example:

V = voltage output of amp in RMS volts
R = resistance/impedance of speaker or load
W = watts delivered to load

Equation for power out:

V^2 / R = W

So a home stereo with a 60 volt power supply, not bridged:

8 ohms:
20 volts RMS ^ 2 / 8 = 50 watts

4 ohms:
400 / 4 = 100 watts

1 ohms:
400 / 1 = 400 watts


Car stereo bridged without inverter:

10 volts RMS output (typical) into 4 ohms:

10^2 / 4 = 100/4 = 25 watts (sound familiar to the output of most car units?)

2 ohms:
100 / 2 = 50 watts

1 ohms (Bose speakers in some cars like Maxima, etc):
100 / 1 = 100 watts


All of the above equations assume that there is enough current output in the amplifier to drive a low impedance load.



So, an educated guess on the current system would be that the 2-ohm mid-range through bass speakers is getting a max of 50 watts each.

The tweeters do NOT need as much power as the bass system does, so they are probably getting 25 watts.


[ 08-10-2001: Message edited by: EricL ]

 

EricL, you still have your Maxima?

 

Thanks ericL for your additions. I am glad someone understands these things.

 

Nop...

 

Ok, I have a question for you guys. I have a 5 channel amp right now thats just pushing a 10 inch sub. It's a 4 ohm amp. Can I hook up the factory speakers to it or will it mess anything up?

 

Alllllrighty then, some good audio techie talk. Probably the most important comment made in the above thread was that "all of the above equations depend on the ability of the power amplifiers to supply the current into the low impedance loads". Bingo. Most power amplifiers, unless specifically designed to operate into low impedance loads (i.e., < 4 ohms at frequencies where the input signal has a large amplitude) do not have the ability to linearly increase current into a load that is linearly decreasing. At some point, as the impedance decreases, the amplifier becomes current-limited and can deliver no more power without either tripping an internal protective relay or igniting its power supply. The max current rating of the output transitors may also limit the power output.

In reality, the RMS power rating of audio power amplifiers tells you very little about how it will perform playing real music, except as a rough basis for comparison. If you're into listening to music with a life-like dynamic range, the most important performance factor of the amplifier is its ability to deliver high currents to low impedance loads for relatively short periods of time (20 - 50 milliseconds). Unfortunately, that's not a spec you're likely to see on a spec sheet. Its RMS power rating may tell you very little about this aspect of its performance.

Another factor that was not mentioned above is the efficiency of the speakers - roughly speaking, the ratio of the audio power output of the speakers to their electrical power input. If you've got speakers that will produce 98 dB SPL at one meter with one watt input, it doesn't nake a whole hell of a lot of difference what power amplifier you're using to drive them if dynamic range is your main interest.

 

What these ultra-techie guys are trying to tell you is that it's a BAD THING to try to drive your 2-ohm Blowz speakers with a conventional power amp that provides a 4-ohm output impedance.

The actual empirical equation is:

Blowz = hi-fi / 10000 = lo-fi

Use your 5-channel amp (if it's RMS-worthy) and get rid of your Blowz speakers!

[ 08-13-2001: Message edited by: technoid ]

 

Eric L could you send me some pics of your Acura....LowFlight

darkstar@galaxyispc.com

 

Like we've always said, no highs no lows....MUST BE BOSE.
I remember the old days in the early 80's when car audio was fun.
The best imitation I can do is of our old BOSE sales rep.
(put your hand over your mouth and say, "Hi, I am your new BOSE rep" hahahahahahhaaaaaaaaaaa!!!!!!!!

 

1. If you’re talking about "most" stereos, they will tell you the spec for output at a given "impedance". (I also commented about being able to supply the current.)

2. When I setup and designed commercial studio tri-amp systems, we used 400 watts for the low-end, 200 watts for mid-range, and 100 watts for the high-end. I did this years ago for a lot of well known recording studios…

3. Yes, the efficiency of the conversion of a speaker (and its enclosure) is important. However, with that all said and done, as a rule, if you go running through a bunch of catalogs, you will generally find tweeters have much higher efficiencies than woofers.

4. Bose, at least on the 1-ohm output amps, did a good job of supplying current. I can't say the same for their choice of electrolytic capacitors -- they suck. In fact the bulk of the squealing and other problems in the 1-ohm Bose units (in a number of cars) was due to caps. that went to hell in a hurry). It seems they couldn't afford the extra few cents for some good ones...

5. Yes, your right about efficiencies and the rest, but how many people do you know that actually run a pink noise on their systems, and then equalize it properly?

At least someone can figure out a "rough" estimate of the power going to the tweeters and other two speakers. Don't expect Bose to give out the efficiencies for the speakers.

BTW -- most power amps with OUT switching power supplies are NOT current limited, but are limited by the rail voltage in the car. A good way to tell if an amp, car of otherwise has good "current" output and ability to drive a low impedance load is to see if an 2-channel amp, when bridged, will put out 4 times the power. A good shop will probably have already done the car and can recommend some good replacement speakers and amps...

 

1. If you’re talking about "most" stereos, they will tell you the spec for output at a given "impedance". (I also commented about being able to supply the current.)

Agree, usually 4 or 8 ohms...just a nominal figure that's only goof for a basis of rough comparison..

2. When I setup and designed commercial studio tri-amp systems, we used 400 watts for the low-end, 200 watts for mid-range, and 100 watts for the high-end. I did this years ago for a lot of well known recording studios…

Ok, must have been fun...

3. Yes, the efficiency of the conversion of a speaker (and its enclosure) is important. However, with that all said and done, as a rule, if you go running through a bunch of catalogs, you will generally find tweeters have much higher efficiencies than woofers.

That's because they (tweeters) have to do less work. I was primarily referring to a speaker system as a whole.

4. Bose, at least on the 1-ohm output amps, did a good job of supplying current. I can't say the same for their choice of electrolytic capacitors -- they suck. In fact the bulk of the squealing and other problems in the 1-ohm Bose units (in a number of cars) was due to caps. that went to hell in a hurry). It seems they couldn't afford the extra few cents for some good ones...

5. Yes, your right about efficiencies and the rest, but how many people do you know that actually run a pink noise on their systems, and then equalize it properly?

I was just pointing out that the original question was how much power was required to drive some certain speakers, and no one had commented on the single most important factor that would lead to an accurate answer tothe question - what is the speaker efficiency...

At least someone can figure out a "rough" estimate of the power going to the tweeters and other two speakers. Don't expect Bose to give out the efficiencies for the speakers.

Wasn't disputing any of your calulations, they're fine, but as you say, there are a lot of caveats that have to go along with them.

BTW -- most power amps with OUT switching power supplies are NOT current limited, but are limited by the rail voltage in the car. A good way to tell if an amp, car of otherwise has good "current" output and ability to drive a low impedance load is to see if an 2-channel amp, when bridged, will put out 4 times the power. A good shop will probably have already done the car and can recommend some good replacement speakers and amps...

I have to take issue with what you're saying here. Yes it is true that the power output of an amplifier is limited by the supply voltage unless it's Class H or something funky like that. However, this is only true to the extent that the amplifier is able to supply the current required by the load. If a load is difficult enough to drive, it may be that the amplifier is indeed "current limited", since it is unable to deliver the current demanded by the load. It's a simple matter of physics that conventional transformers & capacitors in the power supply have a limit on the amount of sustained current they can deliver to the output transistors. No matter what the rail voltage, if the power supply can't deliver the curent to a low impedance load, the amplifier is current-limited.

 

call me crazy. I replaced my speakers too, but I don't think the factory system is bad at all considering it's a $30k car. I've been in a lot of other cars that cost a lot more. Their systems were not even close. just a thought