Hello board,

Well this weekend I bit the bullet and finally installed a cd/radio, and speakers.

The head unit is blaupunkt heidelberg. 25 rms/ 40 peak. The speakers are alpine 5 1/4" 1329s(front doors), and alpine 1029s(4", rear doors).

It was an interesting experience getting the riveted speakers removed from the rear door. I used my dremel to destroy the rivet heads(4). The 1029s fit right into the same spot, accept I head to trim a little around the diameter, and I also had to trim so that clips for the screws would reach the screw holes. After that, no problem.

In the front, I wanted to use the same mounts that carried the " volvo speakers", but the screw hole pattern was just a little off. I was able to get two screws in. Cool, Ill use a little gorilla glue. No problem.

However, the volvo screen fit fairly good on one side, but the other side keeps popping off whenever I close the door. I really want to avoid removing the mount because its such a weird place for a speaker. Im thinking that a bit of gorrilla glue could solve this problem as well.

One other item: the head unit specs 25 rms and 40 peak. The speaker spec 20 rms and 40 peak. I was told the rms = peak divide by 2. Is that correct.

At any rate is my head unit going to limited by these speakers?

The system sounds good.

Thanks for any comments.

Well Lawrence, you just received two identical posts within an hour of each other. To me this means two things: A)There's a good chance we're both right and you should take our advice, and B) Rule #2 on this board is to read other people's replies to a post before replying yourself to avoid this situation. I hope we were of service.

Hahaha, that's awesome. For some reason, when I read the original post and started replying, your post was not on here yet. I think I took a break in the middle of writing my post, that must be why.

Greg

Sounds like what I will be doing soon. I already installed one of the front speakers. I used 5 1/4 like you. I also have a 90 240.

On my front speaker, like you said, the holes don't line up, but I just held the speaker in there and drilled new holes right thru the plastic spacer. 4 screws hold it in.

I noticed one thing about the Volvo grilles. Your car probably has grilles that say "volvo" in white at the bottom, like mine did. If you go to a junkyard, you can find grilles that don't say "volvo" and on these grilles, the metal screen domes out more, so they will provide more clearance for the speaker in there.

As for power ratings, I usually ignore the peak ratings on the amp. It is good if the power rating of the amp exceeds the power rating of the speaker. This is because most speakers are damaged by "clipping" which happens when the amp reaches it's limit. If the speakers are the limiting factor, you will start to hear the sound distort when you really crank it, but the amp will not be at it's limit, and you won't burn out your speaks.

I have never heard of a speaker being damaged because it was overpowered. When you hear it distorting, then you know not to push it any more.

Greg Wong

Sounds like you made good choices with the stereo equipment. It looks like glue is the only way you're going to get the grilles back on. Lucky you. I had no idea 5.25"s would fit in there. I've got 6"s mounted in the bottom of my doors. I had to cut and fabricate all mounting myself. I mounted the tweeters in the original 4" speaker holes behind the grilles. I had to superglue the grilles on, but it worked.

As far as the limitations inherent in a slight power mismatch between amp and speakers, don't worry about it. There are two ways to mismatch power, too powerful an amp, or too powerful speakers. In your case, the amp in the head is capable of blowing the speakers after high volume for a while, but you'd be able to hear the distortion, which is the speaker's cry for help. It shouldn't be a problem. If the amp was weaker than the speakers, then a situation can occur where you turn the volume up as high as it goes, and the amp starts sending a 'clipped' signal to the speakers, which can destroy them much more quickly than a too powerful amp.

As far as determining rms wattage by cutting peak wattage in half, it is usually the case, though there are variances depending upon brands. As far as speakers go, there are BS companies out there which will advertise a subwoofer as "500 watts" which is an overestimation of even the peak wattage, and the rms or 'continuous' wattage is really like 150. I'd watch out for that kind of stuff. In the world of speakers and amps, peak wattage is a functionally useless figure. Happy listening.