QuestionCleggsan,
Thank you for your quick and very informative response! Amazing this kind of service is available free of charge, and it's much appreciated.
To follow up (I'll make it brief), I have no idea the make and model of the PA speakers, so there's no way to know what they can handle, but I'm sure the suggested amp will be sufficient (given its economic price). Also, the speakers are enclosed in your standard PA boxes. I'll have one in the trunk and the other in the backseat as there's only enough room for one in the trunk. I don't think that'll be an issue.
The only question I had related to the amp you suggested:
» 65 watts RMS x 2 at 4 ohms (100 watts RMS x 2 at 2 ohms)
» 200 watts RMS x 1 bridged output at 4 ohms (4-ohm stable in bridged mode)
If I do happen to find out that the speakers are 8 ohms, is this going to be a problem? I see nothing about 8 ohms in the above. I've read that running a system with a difference in ohms will lead to the eventual degregation of the equipment. This wrong? Or is it not a big deal?
Thanks in advance,
Dave
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Followup To
Question -
I'm a musician who just purchased a used car. I've got various equipment laying about and have decided to put a pair of somewhat cheap but decent PA speakers in my car for no particular reason. I've got one in the trunk and one on the back seat. I've got to assume they're 8 ohm, and that they can handle the average amount of power; there's no marking on them. They're probably 10 or 12" with tweeders.
The current deck is a Kenwood KDC 1011s, and 2 'normal' (but upgraded I think from factory speakers) 4-ohm speakers in the rear. 2 factory speakers in the front that aren't too audible.
Without thinking I rewired the PA speakers into the 2 rear 4-ohm speakers in series, and of course, didn't get much out of them. So I was wondering if you could make a recommendation as to what amp (or type of amp) would be best suited for my situation.
Nothing fancy, nothing hugely expensive, but I wouldn't mind using the PA speakers as sort of make-shift subs to be used for all genres of music. Can I patch in an 8 ohm amp to strictly power the PA speakers?
Answer -
Sure, it sounds like an alright thing to do.
Here is my recommendation:
ONE: Measure the dc resistance of the PA speakers with an ohmmeter. (If you don't have one, take them to an electronics shop where they have one and ask them to do it.) An 8 ohm speaker will have a dc resistance of around 6 ohms. A 4 ohm speaker will have resistance of about 3 ohms. Then, you will know the impedance of the PAs.
TWO: I checked the specifications of your unit with the Kenwood manual and you do have preouts that will drive an external amp.
THREE: If you give me the make/model of the PA speakers I can tell you what kind of power they will handle. If they are properly loaded acoustically, they should not need a big power amp to drive them.
FOUR: Are the PA speakers in their manufacturers box? Are they in any box? They should be in an appropriately designed box in order to get the full performance out of them; especially if you want to emphasize their bass output you will need them properly loaded (acoustically) so they produce what you are expecting. PA speakers work good when mounted in infinite baffle style enclosures; like in the trunk of a car in a big board that seals the trunk off as the baffle box. But, let me know and I can help you with the installation details. OR: you can find lots of advice and instructions on car boxes by doing a google search.
Hope this helps, but let me know more after you have studied my response.
Cleggsan
PS: I am sure this amplifier would be sufficient for the purposes you propose.
http://www.crutchfield.com/S-SBcYc3wiGXN/cgi-bin/ProdView.asp?g=120&I=489AP400&s
AnswerNo problem if the impedance is higher than the rating of the amps. Trouble if it is lower.
So, in your case no problem. Most PA speakers are either 8 or 16 ohms. I have never seen a 2 ohm or 4 ohm PA speaker. The reason amps are rated at 2 ohms is because many users parallel two 4 ohm speakers thus putting a 4 ohm load on the amp.
Bottom line: You should be okey.
Cleggsan
