My Volvo Speaker says 4 ohm, why does everyone say 8 ohm?

[PDLarson]

I know some people are tired of speaker threads and I ended up posting a question in another thread but I didn't want to hijack it even though my Q was somewhat related. My twist is that I have 4 ohm OEM Volvo speakers but I keep reading that Volvo uses 8 ohm speakers.

I am working on door panels, noticed that one of the stock speakers was bad, went to the JY to get the only locally available replacement and it was worse than my bad speaker. My door panels were supposed to be done and I wanted to get something (yes rushing things, 1st mistake) so I went to the local stereo shop (2nd mistake?), talked to a guy who has been there forever and who I do actually trust. We did not discuss the intricacies of Volvo systems, just identified + and - on my OEM speaker. Anyway, found a nice pair of Alpine 6.5 inch component speakers SPS-610C, disassembled my OEM speakers / mounting standoffs and installed the new speakers. The fit is fine but now I'm not so sure that the sound is right.

I referred back to several forum posts and everything seems to indicate that Volvo used 8 ohm speakers wired in pairs so that the radio sees 4 ohms as most car head units, OEM or not, seem to expect. I think I follow that reasoning so I started second guessing myself and began shopping for 8 ohm 6.5 inch speakers. I do want to figure out frequency response of the OEM speakers to help identify the correct aftermarket 8 ohm 6.5 inch speaker. But then I looked again at one of the front door speakers I pulled:



So what the heck?! I thought Volvo speakers were 8 ohm? Not the pair I pulled from my front doors! So now I think ok, if I had 4 ohm speakers and installed 4 ohm speakers I'm golden right? Well something still doesn't seem quite right. It sounds too tinny, almost like the bass is disconnected from the rest of the audio, just not right. There is still bass coming from the back doors but those by themselves do not make enough bass to sound correct in the front seats. And I don't mean I am trying to get everyone around me to hear that I am rockin' the Volvo. Regardless of the type of music, at anything above really low volumes, it seems clear that there is not enough bass.

Possibilities:
1) I have replacement speakers with a wildly different frequency response range
2) Maybe the crossover on the new speaker should be removed. I don't think so and I hope not, I don't think it can be without destroying the speaker. From Crutchfield: "The Alpine SPS-610C features low-pass crossovers attached to each woofer's input terminal and high-pass crossovers in-line with the tweeters' speaker wires." My thinking here is that perhaps the HU is only putting out the frequencies that should be going to that speaker (internal crossover in the HU basically so the speaker doesn't need a crossover)
3) The Alpines came in a set of two pairs, two 6.5 inch speakers and two tweeters. The tweeters are designed to hang off of the 6.5s, not wired directly to the radio. When I bought them I figured the 6.5s are basically what I am replacing and I just will not use the tweeters. Well if the box says the speakers are 4 ohm (doesn't clearly say each), maybe they are 4 ohms when wired as a pair. In other words, maybe the Alpine 6.5s alone are not 4 ohm.

Here is what I plan to do for now:
Try to research if the Alpine 6.5 inch speakers are 4 ohm by themselves or only when wired with the tweeters
Try to find out if having two crossovers messes things up (if the radio has this function built in alongside a speaker mounted crossover)
Try to identify the frequency response of the OEM speaker
See if I can figure out how to test for myself with a multimeter, what the ohm ratings of speakers are. I know they may not be exact but maybe they should be approximate.

But my single main question, why is this speaker clearly labeled 4 ohm when everyone says Volvo speakers are 8 ohm?

This thread has more pictures

[quahog pearl]

Consider the possibility that someone replaced both front speakers with JY units from an older Volvo before you bought it. Note that "94" is stamped on your 4 ohm speaker - many OEM parts have a date stamped or cast into it. Sounds like you are carefully considering many variables to get things right. Other folks would say "it fits into the hole and it says Volvo-done"

I purchased a 95 GLT earlier this year and have a way to go before the "hacks of yesteryear" are expunged from this car. A better way to describe them would be "rape" . But the car runs well, and I like it. All I'm saying is don't assume that all repairs were made properly.

[PDLarson]

Thanks for the quick response. I do know that the door panels had been off before. I "ASSumed" to repair the black brackets that come unglued over time as they were clearly re-glued. Maybe those were re-glued because they popped off when removing the panels to get to the speakers. Interesting possibility. I have a total of three OEM speakers, two that came with the car and one I pulled from a '99 S70. Yes, I actually saved the messed up speakers that I separated from the mounting standoff bracket / known bad one from a JY. I did notice the 94, another one has 88 stamped on it but I didn't really think much of it. The three speakers are mixed up and I don't know what the third says but I'll check. I also just remembered a '99 V70 AWD that should still be complete in one of the lesser visited JYs. maybe I need to pay it a visit.

[fazool]

Apologies for the terse response - I am at lunch and only have a minute:

The head unit (radio/stereo) is built to connect to 4-ohm channels, as are all standard automotive systems.

So, you could connect a single 4-ohm speaker in to each channel and be fine. Or, you could combine TWO 8 ohm speakers in parallel (creating 4 ohm impedance) and be fine. Or you could connect FOUR 16 ohm speakers in parallel (creating 4 ohm impedance) and be fine.

So, you see, it depends no how many speakers are connected.

If you only have a single speaker (such as a door) then it would typically be a 4 ohm speaker.

If you two speakers (such as door and dash) then they would likely be 8 ohm speakers.

[MoVolvos]

Apologies for the terse response - I am at lunch and only have a minute:

The head unit (radio/stereo) is built to connect to 4-ohm channels, as are all standard automotive systems.

So, you could connect a single 4-ohm speaker in to each channel and be fine. Or, you could combine TWO 8 ohm speakers in parallel (creating 4 ohm impedance) and be fine. Or you could connect FOUR 16 ohm speakers in parallel (creating 4 ohm impedance) and be fine.

So, you see, it depends no how many speakers are connected.

If you only have a single speaker (such as a door) then it would typically be a 4 ohm speaker.

If you two speakers (such as door and dash) then they would likely be 8 ohm speakers.

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+1 - Be sure to understand what fazool is saying in terms of hooking up your speakers in parallel or series in order to match the Impedance of the Head Unit. Not matching Impedance can either give you poor sound or worst burn up your Amp.

Meditations on Speaker Impedance ("OHMmmmmmmmm")
http://www.prestonelectronics.com/audio/Impedance.htm

Blessings,
BKM
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[MoVolvos]

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Hi PDLarson,

Separate Frequency Response, Cross Overs and Impedance!

FR tells you what range of sound from Low (Bass - Woofers) to High (Treble - Tweeter) can a speaker or combination of speakers can reproduce. Bass requires air movement so the size of the Woofer (in simple terms) make a difference how boomy a speaker can produce. The Tweeter is self explanatory.

A Typical Two Way Speaker can have a Woofer which is not filtered and pass all frequency ranges of Low, Mid and High Frequencies and the Tweeter get a Capacitor to filter out the Low and Mid Range Freq. If the Capacitor do not filter out the Low and Mid Freq. the poor little Tweet will try to move like the Woofer and get cooked.

A Cross Over is a combination of filters to restrict High Freq to the Woofer and Low Freq to Tweeter. The designer is trying not to filter any sound out through out the entire Freq range (Very Difficult) so there is no gap in the sound: Lacking Midrange Sound so it sounds too Boomy and to Tinny. So the Cross Over is trying to bridge that gap or crossover the mid bass enough to the Tweeter without damage and vice versa filtering out the Mid-highs to the Woofer so it just reproduces mostly Bass. If you have 3 speakers in one or 3 Way Speaker the entire range (Freq) of sound the speaker is capable of producing is divided by the Crossover to each of the speaker so no gap is missing in the reproduction of music. Low, Mid and High Frequency to each perspective speaker and no gap in between. Very difficult to get great bass from a 6 1/2" speakers due to size of speaker, enclosure, magnet size to AMP capabilities.

Whatever you do follow manufacturer wiring diagrams to match the Impedance of the Head Unit and do not remove or modify Filters or Capacitor to make adjustments to Impedance!!

Blessings,
BKM
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[PDLarson]

"Meditations on Speaker Impedance ("OHMmmmmmmmm")," I like it and no apologies needed fazool, I appreciate the replies. After a little more research, here is what I found. All of these pictured speakers are from 1999 MY 70 series cars. The one from the S70, I'm not sure if it had dash speakers or not, I assume it did but I didn't notice. Were there any without the little dash speakers, I have no idea. The other two are from my V70XC and it does have working OEM little dash speakers and front door speakers and rear door speakers and the little ones in the rear cargo area pillars, 8 speakers in all, four pairs if you like.




So the stamped dates don't mean anything unless the one stamped 12 is 100 years old or brand new. I suspect the code on the right of the label is a date code, they are 98W36 (from the S70) 99W16 and 99W15 from my car. I suspect this is the year and week of the year that they were made. Notice also, these are the correct part numbers for this car so I don't think they are from the wrong car. Also, I was able to figure out after looking at all three which one was from the S70, the paper cone is faded much differently from what was originally in my door.

We have all heard that these cars need 8 ohm speakers but mine with the 8 speaker system has 4 ohm speakers. Or am I missing something?

Now electrically, I do understand series and parallel but I am just showing what came out of my car with an eight speaker system. I don't know how it is wired. I mean, I just want to disconnect one and reconnect another. I don't know what the wiring harness(s) / HU do behind the scenes. I am just wanting to do a simple speaker swap. Should it be 4 or 8 ohm? And why 8 ohm if the one that came out is labeled as 4 ohm? Are we just assuming that the HU / amp expects 4 ohms per channel? Four pairs of 8 ohm speakers in parallel makes perfect sense so that the HU "sees" four 4 ohm channles so that must be what Alpine / Volvo did and everyone repeats it but is that correct? I'm not so sure. Maybe it sees eight 4 ohm channels?

Now I have to go find the wiring diagram for the radio connectors. If it is wired for eight channels I say the 8 ohm theory is bogus. And I am not trying to get a short tone with anyone, I just want to figure out what is really going on and maybe stop spreading the 8 ohm info if it is not correct. What does your P1 V70 have?

Series Connections:
If both of the speakers have an impedance of 4 ohms, the total impedance will be 8 ohms
If both of the speakers have an impedance of 8 ohms, the total impedance will be 16 ohms

Parallel Connections:
If you have two 4 ohm speakers connected in parallel, the total impedance is 4/2 or 2 ohms
If you have two 8 ohm speakers connected in parallel, the total impedance is 8/2 or 4 ohms

From: http://www.swedishautoparts.com/S70/vol ... parts.html
SPEAKERS AND SPEAKER GRILLES Volvo S70
APPLICATION PART #
S70 1998-2000 Speaker Driver Side Front Door OES 3533620
S70 1998-2000 Speaker for Rear Door fits either side OES 3533622
S70 1998-2000 Speaker Passenger Side Front Door OES 3533621

Maybe that was a bad example as it only says S70 but I have seen classified listings where people have parted out V70s and listed these same part numbers and other parts sites show this part as S/V70 so I am pretty confident this is the correct part number for either the S or V 70.

[MoVolvos]

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Just to kind of clear the deck for a moment if the wiring on the HU and Speakers are OE it would be safe to replace each speaker with 4 ohm speakers. The likelihood of someone replacing all eight speakers from 8 to 4 ohms is not plausible as this person would have to know so much but not enough Electronics to somehow thinks it is the right thing to do to match the Impedance of the HU or AMP.

Let us know what you find in terms of wiring diagrams as there seems to be 4 and 8 speaker systems(?) but I am assuming there will potentially be an external AMP to handle those extra speakers.

Blessings,
BKM
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[PDLarson]

All I have to say at this time is hmmmmmmmmm, very interesting. The front door has the correct P/N and is labeled 4 ohm. This rear door speaker is the correct part number for this application and is labeled 8 ohm. Here is the rear speaker:


Polarity:
Although the front speaker is not labeled, the rear is labeled and it is the same as the front; the keyed part of the connector is + and correlates to the 1 on the plug so 1 is +, 2 is -. The numbers on the plugs are hard to find.


Interesting enclosure. This speaker produces much more bass in this enclosure, than the OEM or the Alpine replacement SPS-610C in the front doors which have much less of an enclosure. Apparently this enclosure is designed to take advantage of the open space in the door.

[MoVolvos]

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The enclosure like the Bose Systems count on the acoustical enclosure to help create/enhance the sound. As for the 8 ohms in the Rear Door is it in parallel to the Rear Deck Speakers? Look to see if they are 8 ohms also.

Blessings,
BKM
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