A

anurse

Audiophyte
<font color='#000000'>I plan to purchase a replacement for the largest speaker (8 inch) in a beautiful Bolivar Model 18 speaker. I purchased a set about 1978. It started making a gross sound when the kids cranked it up. I need to know what to purchase.

The back of the speaker notes: &quot;System Impedance 4 ohms&quot;

I use a Pioneer receiver SX 550 purchased in about 1978. It is in great shape. The back of the receiver notes: &quot;A/C 120 volts 60 Hz 80 watts.&quot;

Then it (the receiver) notes:
Caution Speaker impedance
A,B----------4 ohms More/Speaker
A+B---------8 ohms More/Speaker

I don't know what any of these letters mean.

Questions: Please recommend an 8 inch replacement. Do I have to use a 4 ohm? I have 4 slots for speakers, but only use two. Does the info above mean if I use 2 speakers, I could/should use 8 ohm? Do I have to replace both 8 inch speakers, if the other one is OK? Could I use a woofer?

These questions in themselves likely reveal an element of my ignorance in the field.
My main question...What speaker do I replace with? The current speaker does not provide a clue.

Thanks for your help.</font>
 
J

Jack N

Audioholic
<font color='#000000'>&quot;System Impedance 4 ohms&quot;  The speaker manufacturer is telling you how much electrical &quot;resistance&quot; to energy flow that this particular model speaker has.  The lower the number, the smaller the resistance, which means more power output from the amplifier. However there is a direct trade-off here.  Not only does a lower number mean more power output from the amplifier section, it also means increased musical distortion (and a lot of other things that I won't get into). There isn't a right or wrong answer, it's just what you prefer - louder sound, or cleaner sound.

The back of the receiver notes: &quot;A/C 120 volts 60 Hz 80 watts.&quot;  This is simply how much current your receiver draws from the electical socket in the wall.  It would be safe to assume that the amplifier section of your receiver is probably rated at somewhere around 40 watts per channel.

&quot;I don't know what any of these letters mean.&quot;  The A / B designations are for pairs of speakers being used. The first pair of speakers would be speaker pair &quot;A&quot;. If you're using 2 pairs of speakers, the second pair would be designated as &quot;B&quot;. So if you were using only 1 pair of speakers at a time, you could use speakers with any Ohm rating down to 4. However if you were going to be using both pair of speakers at the same time, each speaker used must have an Ohm rating of 8 or more (this is part of Ohm's law, which I won't get into here). It sounds like you are using a single pair of speakers, so your 4 ohm speakers aren't doing any damage to your amplifier.

&quot;Do I have to use a 4 ohm?&quot;  No. If you're going to stay with a single pair of speakers, any ohm rating of 4 or more will work fine. If there's a possibility that you'll be adding another pair of speakers at some point down the road, you'll want to use speakers with an ohm rating of 8 or more.

&quot;Do I have to replace both 8 inch speakers, if the other one is OK?&quot; You don't have to but it's highly recommended because each speaker cabinet has it's own &quot;accoustic signature&quot; (called Timber). In other words, one speaker would sound noticeably different than the other one, and it would be next to impossible for you to get the tone that you like using your bass &amp; treble controls. For all practical purposes, replace both speakers.

&quot;Could I use a woofer?&quot;  I'm not sure what you're asking. If you're asking if it would be ok to replace just the one defective driver, I wouldn't recommend it for 2 reasons.  1) The odds of finding an exact replacement for that vintage speaker is next to zero. If you use something other than an exact replacement, we're back at the Timber thing again.  2) There's no guarantee that the driver is what's causing the problem. It could easily be another component(s) inside the speaker. And even if it is the driver, with a speaker that's that old, the other components in the speaker probably are about on the verge of failing also.

There's a possibility that the speaker isn't the culprit here. Your receiver may be at fault. Turn the receiver off and mark each wire on the back of each speaker so you know which one is &quot;+&quot; and which one is &quot;-&quot;. Now disconnect the speaker wires from each speaker and switch the speakers to the opposite sides (right side to left side, and left side to right side) and hook them up again making sure that the &quot;+&quot; gets hooked to the &quot;+&quot;, and so on. Turn the receiver back on. If the bad sound is now coming from the other channel, the speaker is bad (IE: If the bad sound was originally in the left channel and is now in the right channel). If the bad sound is still coming out of the same channel, the receiver is bad (IE: The bad sound stayed in the left channel). If the receiver is bad, it's not worth fixing. Buy a new receiver.

If the speaker is bad, don't get hung up on driver sizes. Buy what sounds good to you. That's all that matters. Tell the sales person that you need speakers that will handle 40 watts per channel (don't forget to tell him/her what ohm rating you're interested in also) and listen to many different brands and models.</font>
 
Z

zumbo

Audioholic Spartan
<font color='#000000'>Very, Very good advice. I would like to add that IF you do keep your receiver, and choose to ONLY replace the speakers, be sure NOT to buy speakers that are rated to handle high power, I would look more at db per watt. This is the loudness the speaker will produce with each watt. If you buy high power speakers, you will find yourself cranking the volume up too high, and in most cases, toasting the tweets. Make sure when shopping to have salesman use a receiver rated around 40 or 50 watts, otherwise they will use the best one they have, and when you get the speakers home, you will want to know why they don't sound like they did in the store. Lower power speakers sound WAY better than &quot;high end&quot; speakers on low power receivers. If you do only want to use two speakers, a 4ohm speaker will get more power out of your amp, but as mentioned above, you can ONLY use two. Four will put too much of a strain on your amp. I went with 4ohm speakers on my system to get more out of my amp, it works great!</font>
 
A

anurse

Audiophyte
<font color='#000000'>Thanks for the info zumbo and Jack N.

I looked closely at the speaker making the noise. There was a torn area along the edge in the flexible foam. Having nothing to lose, I heated up my spouse's hot glue gun and placed a bead on the torn area. Results- no noxious noise (for now).

I expect this is only a temporary fix. The tweeter and mid (I hope these are the correct terms) appear ok. The other entire speaker seems ok.

When the speaker starts to act up again I do plan to replace the woofers (I think this is the term for the largest speaker in the box) with two 8 inch 4 ohm speakers (or is the term woofer appropriate here?) that will handle 40 watts. Does this sound correct?

Thanks again for your help.</font>
 
Z

zumbo

Audioholic Spartan
<font color='#000000'>Yes, &amp; in the future, a permanent fix for a tear is clear fingernail polish. This is the best fix also!
I replaced a woofer in my old Cerwin Vegas due to the fact that the foam surround was 14 years old and tore all the way around. I replaced it with a 15 dollar 12&quot; woofer from Radio Shack. &nbsp;
I have you know that bad boy sounded pretty darn good. I am not sure if they would have a 8&quot; 4ohm woofer, but it can't hurt to look. If it doesn't sound good, just take it back &amp; tell 'em it wouldn't fit!
</font>
 
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G

Guest

Guest
<font color='#000000'>You can also replace foam surrounds yourself. &nbsp;It is not hard at all. &nbsp;I have fixed a pair of Mission 707's and an old Inifinity sub and they came out sounding fine. &nbsp;You will need to scrape off the old surround with a razor, and remove the dustcap to shim the voicecoil. Then you can glue on the new surround. After the glue is set, you can remove the shims, and then replace the dustcap.

Go to: www.winstonorgan.com &nbsp;

They have all types of kits to repair foam surrounds. &nbsp;You can give them a set of measurements, and they will hand pick the surrounds for you. &nbsp;If you don't want to do it yourself, you can always take the speaker to a reputable shop and they an do it for you. &nbsp;Hope this helps.</font>
 
S

simplman63

Enthusiast
<font color='#000000'>Hey, that's what I was gonna say...
</font>
 
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Z

zumbo

Audioholic Spartan
<font color='#000000'>I needed that. I might try to replace that old Cerwin surround now. Hope it sounds as good as the Realistic!
</font>
 
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P

phillyguy

Enthusiast
<font color='#000000'>IMO, refoaming is a easy way to breathe in new life into an old set of speakers. With older speakers, it is difficult to find exact replacement drivers, unless you have a very popular speaker, like the old Large Advents. &nbsp;It is even more difficult to find a suitable alternate driver. &nbsp;(I had no choice of replacing the driver on my old Infinity RS sub. It was an unusual 2 ohm, high sensitivy woofer, that even Infinity could not recommend a replacement for, nor provide enough specs for that I could even attenmpt to replace it. &nbsp;It was either refoam or throw it out.) &nbsp;

As long as your speakers were not abused, you will be pleasantly surprised how they come out. &nbsp;My old sub buzzed like crazy because of the torn surround. Once fixed, the bass is nice and tight again. &nbsp;It is not hard to do, you just need to take your time and be careful. &nbsp;Removing the old surround takes time, mostly because you are removing old glue. &nbsp;I was dealing with speakers with polypropylene cones, so scraping them wasn't to difficult. &nbsp;I have not done speakers with paper cones, which I imagine would be a bit harder. &nbsp;I did not use any solvents (such as Goo Gone) to remove the glue, beacuse I was worried about affecting the adhesion of the new glue. &nbsp;

Be careful with the new glue, because it is very sticky, and if you use too much, you will have a hard time keeping the new surround clean, since you will pick up glue on your fingers as you work your way around the cone, pressing the surround into place. &nbsp;Even after refoaming 3 speakers, I still get glue on the surrounds. Argh! Luckily, I don't listen to my speakers with the grills off. &nbsp;Also, don't worry if you have an odd size driver that they cannot find an exact replacement for. &nbsp;I had to cut a surround and overlap an edge on my sub, and it sounds and has held up fine.

As far as cost, figure around $30 to $40 for a kit which includes a pair of replacement surrounds, shims and replacement dustcaps and glue. I liked &nbsp;the people at Winston Organ because they took the time to find the best fit surround for my speakers, and were very helpful on the phone. &nbsp;Where ever you choose to buy from, at least make sure they are selecting the surround based on a set of dimensions you provide, not just by saying &quot;it is just a 10&quot; driver&quot;. &nbsp;All &quot;10&quot; drivers&quot; are not the same size. &nbsp;The 10&quot; driver on my sub was actually 10-3/4&quot; (to edge of frame). &nbsp;The other important measurement is the actual diameter of the cone. The difference between those two dimensions is the distance the surround must span. &nbsp;As you can see there are a lot of variables for finding the right surround. &nbsp;

Sorry this got a bit long, but I hope you find it useful.</font>
 
A

anurse

Audiophyte
<font color='#000000'>Thanks much for the info.</font>
 
W

Wouldcarver

Audiophyte
Subs

Total newbie here, but glad I found the site.

Thanks, Phillyguy, for the Inf RS Sub info. I have one, with a blown cone, (foam) and I'm trying to decide if I should pitch it, or try to repair...is the new Sub technology that much better? If so...who? (limited budget, of course)

Thanks for any response.

Wouldcarver
 

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