Question about speaker impedance..

[DSChamber]

Hi... I picked up a pair of Pioneer CS-J835 towers a few months ago for $20... they are in mint external condition with the exception of one of the speakers.

Each speaker has two 8" woofers, a tweeter, and a super tweeter.

One of the speakers has one of it's 8"s and it's super tweeter replaced.

The speakers seem to work fine, they are loud and clear.....

I popped out all of the speakers and had a look.

The Pioneer original 8" drivers (p/n 194492) are all 16 ohm..... but I am not sure what the impedance is of the replacement woofer. It and the super tweeter are Audiosphere. The numbers on the Audiosphere 8" is "W8-5PL5 K3J2"

Here's a couple of questions...

1. Is there any practical way to figure out what the impedance of the Audiosphere 8" driver is?

2. If the Audiospehere is say 8 ohm, will that cause me any issues with the speaker? That would mean I would have a 16 ohm and a 8 ohm woofer being driven....

3. Would there be any benefit to me if I replaced all 4 woofers with 8 ohm drivers? Or would it be better for me to simply replace the Audiosphere with a 16 ohm driver of good quality?

4. Where is a good source for 8 ohm and 16 ohm Pioneer replacement drivers?

 

[bowtie427ss]

1. Is there any practical way to figure out what the impedance of the Audiosphere 8" driver is?

Measure the driver's DC resistance, 8 ohm drivers will typically read between 4.5 and 7ohms, and 16 ohm drivers will typically measure somewhere in the 10-14 ohm range. There are of course exceptions, but the above will cover the majority of speakers.

2. If the Audiospehere is say 8 ohm, will that cause me any issues with the speaker?

Most immediately it will affect the crossover point creating an "unmatched" response compared to it's mating speaker. This may or may not occur to an undesireable or audible degree.

3. Would there be any benefit to me if I replaced all 4 woofers with 8 ohm drivers?

Again it will change the load the crossover sees and affect the crossover frequency of the woofers and possibly the midrange. To maintain the original crossover points and slopes, some component values would likely need to be changed.

4. Where is a good source for 8 ohm and 16 ohm Pioneer replacement drivers?

I'm not sure an exact replacement could be found other than from a "parted" speaker. Parts Express is a great source for may OEM equivalent replacements, but i'm not sure you'll find a wide variety of 16 ohm woofers in 8 inch................. worth a shot tho.

 

[DSChamber]

Thanks for the response Bowtie...

I measured the 3 Pioneer woofers and they all measured 16 ohms with my Multi-meter...

I measured the Audiosphere replacement and it measured 11 ohms....

Weird results? Looking at the Pioneer speakers you can definitely see a difference in the build quality... they look and feel "better" ....

So can I assume that the Audiosphere is a 16 ohm driver but with "sloppy" specs, and the Pioneer's are just a better speaker with tighter specs?

I do know that when I run the speakers hard the Pioneer's really move while the Audiosphere doesn't move as much...

Also... I looked at the label on the front of the speakers and they say that they are 8 ohm impedance.. that must mean that the 16 ohm drivers must be put in parallel...

I measured the DC resistance of the speakers by measuring across the speaker connectors on the back and the one with all Pioneer drivers measured 8.2 ohms, the one with the Audiosphere woofer and super tweeter measured 7.1 ohms...

Is this something to care about or should these speakers be fine and not hurt my Integrated Amp that will be pushing them?

Here's the speakers... anyone see these before, anyone have any spare drivers kicking around...I'd like to replace the Audiosphere drivers with original's

This one has all original Pioneer drivers...

This one has the bottom 8" replaced and the super tweeter replaced...

This is a shot of the front label...

 

[louiszimmerm]

The pure Pioneer tower is , IMHO, a very good looking speaker. If it were me, I would definitely try to match the original components not only to preserve the electronic characteristics, but also the appearance!
Parts Express has Pioneer tweeters. I haven't checked out their woofers, so I'm not so sure about that.
Part of the job of a crossover is to provide a (I'll use the word "stable", although it's certainly not true in all respects) impedance value to the amp. You are not likely to damage your integrated. My hK, while designed to run 8 ohm speakers, will happily drive values al low as two ohms (if I understand correctly, speaker impedance fluctuates naturally as the voice coil moves.)
Louis

 

[bowtie427ss]

So can I assume that the Audiosphere is a 16 ohm driver but with "sloppy" specs, and the Pioneer's are just a better speaker with tighter specs?

Yes safe to assume it's 16 ohm, but i'd not blame the difference that you see between the readings on the different woofers on anything more than different design and construction. Remember this is just DC resistance and in their working environment a speaker should never see DC. For any purpose other than establishing a baseline for a speaker's actual impedence, or designing modeling and building crossovers, that DC resistance measurement is not terribly relevant.

(if I understand correctly, speaker impedance fluctuates naturally as the voice coil moves.)

From what i understand this is absolutely true and is most relative to frequency, most woofers will have an impedence at their resonant frequency that is several times their average or nominal impedence, and even tho a speaker has a nominal rating of say 8 ohms, the impedence can and many times does dip well below this fugure, sometimes to less than half at certain frequencies.

 

[titanstats]

I could be mistaken (it's happened before! ), but isn't the supertweeter in these speakers the aluminum one? Fostex driver, used by RatShack, I believe -- either that, or a perfect clone of one (they are good drivers).

Shouldn't be too hard to find a set of replacement tweeters for these speakers that will match/best the ones that are in there. Cruising ePray for a bit might yield you a replacement woofer in time, if you don't mind waiting.

 

[DSChamber]

Here's a few pics of the tweeters/super tweeters....

This is the one out of what I think has all original drivers, super tweeter I am assuming (edit, just ran the part number 194516 through the Pioneer website and it is a super tweeter and it was found in a lot of CS models, and it's still available!) .... I measured the resistance of this one and it was in the Megs (I think somewhere like 6-7 Megaohms), so this one is shot (it doesn't make any sound either)

Here's a pic of the replacement Audiosphere super tweeter (or it could be a tweeter not sure as it doesn't look like the Pioneer one), this one works and measures 6.4 ohms... he is just the wrong shape

And here's a pic of the tweeters.... I was surprised to see Realistic stamped on the back, which makes me wonder if these are original or were they swapped out some time ago....the both measure 7 ohms and they work fine...I'm thinking they were swapped out because the wiring inside has a "big" spade and a "little" spade connector and these tweeters have two small spade connectors...

So from what I can see I need the following if I want to make them 100% original...

1. One 8" - 16 ohm Pioneer woofer replacement
2. Two Pioneer super tweeters...
3. Two Pioneer tweeters... if the Realistics were not there originally

I wonder if the tweeters/super tweeters out of my HPM-500's will work... will be awhile before I find replacement 10" woofers for those anyway.... hummmm:scratch2::scratch2:

 

[DSChamber]

Since the Realistic bullet horns are working (not sure if these are tweeters or super tweeters??) ....

Maybe I could pop these into where the super tweeters go, they are almost the same dimensions as the Pioneer super tweeter I have in there now..

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=270-100

Bah... nevermind these are 4 ohms....

 

[DSChamber]

Did some digging on the Realistic 40-1310A drivers I have... seems that these are super tweeters and not tweeters like I thought.... they also seem to have a pretty good reputation.... so I think these will stay in the cabinets..they sound really nice, very clean crisp highs that's for sure...

Now I have to figure out what I am going to put in the other two spots..the speakers below the 40-1310's have a smaller mounting hole so I am wondering what went in there originally...

Anyone have these speakers? Anyone have a user manual? I would like to know the specs on the cross over inside the cabinets....