maiku Posted April 22, 2005 Report Share Posted April 22, 2005 you could hook up 4ohm rear decks no problemjust that the rear decks won't get as much power as you'd like Link to comment Share on other sites More sharing options...
Gregg Posted April 22, 2005 Report Share Posted April 22, 2005 Also, do you happen to know if a 5x7 will be an easy fit?←Not all 5x7s will be an easy fit. When I tried Infinity Kappa 5x7s they did not fit into the regular hole in the rear deck. My friend has Diamond Audio 5x7s in his rear deck that fit in the black plastic speaker housing though. Take a look at the top in the pinned section to see what speakers have worked for other people. Link to comment Share on other sites More sharing options...
RK850 Posted April 22, 2005 Report Share Posted April 22, 2005 850 rear deck speakers are NOT 5x7. The size is more like 5.75x8.5. 5x7 will be too small. I put a pair of Boston NX97 6x9s in the OE box and they sound great. The NX97 has small magnet that clears the metal opening under the rear deck. Read my earlier post and pictures here:http://volvospeed.com/vs_forum/index.php?s...53entry204453 RK850 Link to comment Share on other sites More sharing options...
Asinine Posted April 22, 2005 Author Report Share Posted April 22, 2005 Ok, well i returned the 6x9s i bought yesterday and got some Alpine 5x7s and made them work.. or so i thought:Thats with the cover on and off - speakers in both.But when i went to put them in the car the magnet wouldn't fit in the hole in the metal part of the deck, so they are kind of awkwardly above the deck (at the front), but when the rear seats are up you can't see the gap, and even when they are down the gap isn't too much.I'm sure it's not a good idea to have the magnets resting on something metal, but the system sounds good, and finally loud enough to cruise...Audio.... Done!Seacrest.. out!? <- lame! Link to comment Share on other sites More sharing options...
RK850 Posted April 22, 2005 Report Share Posted April 22, 2005 From the picture, it seems you just mounted the speaker in the box. You should put a plate between the spkrs and the box to separate the front wave and the back wave. Plus with the gap you described, your spkrs are losing a lot of bass. To make the rear deck spkrs work and sound great, you need the rear deck and the spkr box seal properly to separate the air in the trunk and the air in the cabin. If you think they sound good now, mount them properly and they'll sound 100 times better.RK850 Link to comment Share on other sites More sharing options...
billr99 Posted April 22, 2005 Report Share Posted April 22, 2005 850 Stereo Systems DemystifiedThe rear door and rear deck speakers are all 8-ohm, wired in parallel, so that the headunit or amplifier sees a 4-ohm load. If you put new 4-ohm speakers in the rear deck, make sure that you remove the rear door speakers and this will solve the problem. Or better yet, get rid of all your rear speakers and get an amp and sub/s.←So just today I put a new pair of 4 ohm speakers in the rear doors and still have the 8 ohm ones in the rear deck. According to my calculator that should produce a load of about 2.5 ohms. The setup sounds good but am I going to hurt the stock amp at all? After all these years of screwing about with cars, I'm still clueless about car audio.Thanks, Link to comment Share on other sites More sharing options...
maiku Posted April 23, 2005 Report Share Posted April 23, 2005 actually, it should only have a load of 6 ohm per rear channel Link to comment Share on other sites More sharing options...
Gregg Posted April 23, 2005 Report Share Posted April 23, 2005 actually, it should only have a load of 6 ohm per rear channel←Actually, it is about 2.7 ohmsRt = (R1 * R2) / (R1 + R2) Looks complicated, but it's not. Some examples follow. All numbers are in ohms. Let R1 = 8, R2 = 4, then Rt = (8 * 4) / (8 + 4) = 32 / 12 = 2.7 ohmsWhat Do Speaker Impedances Mean?Wow, just found this page, and it really does a good job of explaining ohms (b/c I didn't really understand before) Link to comment Share on other sites More sharing options...
Asinine Posted April 23, 2005 Author Report Share Posted April 23, 2005 Well i'm going to be honest here and admit that i'm still pretty confused about this whole ohm thing.Based on that, right now i have the 8ohm rear door speakers unhooked, so there is just a 4ohm 'load' along that parallel, if i were to hook the door speakers back up then i would be down to a 2.7ohm load which would be bad?Or would it be bad, can the Volvo amp go that 'low'? Link to comment Share on other sites More sharing options...
Gregg Posted April 23, 2005 Report Share Posted April 23, 2005 Well i'm going to be honest here and admit that i'm still pretty confused about this whole ohm thing.Based on that, right now i have the 8ohm rear door speakers unhooked, so there is just a 4ohm 'load' along that parallel, if i were to hook the door speakers back up then i would be down to a 2.7ohm load which would be bad?Or would it be bad, can the Volvo amp go that 'low'?←Correct, right now you have a 4ohm load. Hook the rear door speakers back up and it will be 2.7ohms. I don't know if this is bad or not, so I would talk to Bing.Are you sure you have a Volvo amplifier? From what I understand (from the Volvo Owners' pages) '94 850s and 850Turbos did not come with a separate amp. All the speakers were powered by the headunit. Link to comment Share on other sites More sharing options...
Asinine Posted April 24, 2005 Author Report Share Posted April 24, 2005 Well that would be ideal - or would it?Do you know what speakers i will fry if i hook up my doors and they don't work - the doors or the decks based on this ohm calculation stuff!? Link to comment Share on other sites More sharing options...
Gregg Posted April 24, 2005 Report Share Posted April 24, 2005 Well that would be ideal - or would it?Do you know what speakers i will fry if i hook up my doors and they don't work - the doors or the decks based on this ohm calculation stuff!?←I don't think anything will fry if kept at low volume levels, but the quote below is from that link I posted.If you have two speakers in parallel, the higher impedance speaker takes less power. For example, for an 8 ohm and 4 ohm speaker in parallel, the power shared is inversely proportional to the resistance, so the 8 ohm speaker absorbs half the power of the 4 ohm speaker. You have to keep this in mind, because if the two speakers above have the same power rating (50 watts for example), one of them will hog much of the power, making the combination's power rating not 100 watts, putting one speaker at risk of failure. Link to comment Share on other sites More sharing options...
Asinine Posted April 24, 2005 Author Report Share Posted April 24, 2005 Alrighty, no door speakers it is! Link to comment Share on other sites More sharing options...
billr99 Posted April 26, 2005 Report Share Posted April 26, 2005 Darn, I knew those days I fell asleep in high school electronics would catch up to me one day. Didn't know it would be 35 years later!Since you guys are really into this and all I really want is reasonable sound, plus I'm way too old for something loud; would replacing the stock rear deck speakers with some 4 ohm speakers (along with the 4 ohm jobs I just put into the rear doors) and still keeping things wired in parallel be OK? You would still be looking at slightly above a 2 ohms deal running through the stock Volvo amp. Or would it be better to re-wire in series, ditch the whole thing and start over, ......?Anyone care to try and help the old guy out here? Guess things have changed a bit since I got rid of the 8 track.Thanks, guys Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.