Monitor 7 tweeter problem ??

xenonsky

Hi All,
I have a pair of vintage Monitor 7 Series 2 speakers which I believe the tweeters on it are SL2000 (with foam surrounding the tweeter). Recently I find one of the tweeter do sound a lot less bright then the other one and it seems to play lower in volume than the other side. This one problem side also seems to play less loud overall than the other side of the two speakers.

Does this sounds like I have a blown tweeter?
Or I may have problem with the cross-over?
Would replacing aging cross over help with overall sounds quality?

Thanks,

xenonsky

F1nut

You have SL2500 tweeters.

Take the "bad" tweeter out and swap it with the good tweeter. If the problem follows, you have a bad tweeter. If the problem stays with the original speaker, you probably have a bad polyswitch on the crossover board.

xenonsky

Thanks for the suggestion, I'll give that a try.

I do have a pair of Monitor 5jr+ with SL2000 tweeters, if the tweeters on my Monitor 7 is bad and I take the ones from my Monitor 5jr+ and please them Monitor 7. Would there any problem?

Similarly, if i have a have bad polyswitch on the Monitor 7 cross-over and I swap my Monitor 5jr+ crossovers to Monitor 7, will that cause any problem?
I assume the crossover points are the same given the speakers in them are pretty much the same except for the passive radiator size.

Thanks.

comfortablycurt

The SL2000's and SL2500's used different crossover circuits for the high frequencies, so the two drivers(or XO's) aren't interchangeable.

xenonsky

I didn't realize that, I suppose if I can't locate either a replacement tweeter or crossover for my Monitor 7 (or if cost too high). If I swap out everything (tweeters, mid-bass, terminal post plate with crossover) from my Monitor 5jr+ to Monitor 7 except the box and passive radiator, would that work fine and essential making it sounds like a 5jr+ with more bass? Any problem you can see do doing such swap?

comfortablycurt

xenonsky wrote: »

I didn't realize that, I suppose if I can't locate either a replacement tweeter or crossover for my Monitor 7 (or if cost too high). If I swap out everything (tweeters, mid-bass, terminal post plate with crossover) from my Monitor 5jr+ to Monitor 7 except the box and passive radiator, would that work fine and essential making it sounds like a 5jr+ with more bass? Any problem you can see do doing such swap?

Polk has replacement tweeters available. They're a big upgrade over the stock tweeters as well. You can contact them at the number at the top of this screen. Mention that you're a Club Polk member for a discount.

IIRC, they cost about $48 each. They're worth every penny too.




I'm not sure about that swap. The 5Jr+'s and the M7 SII's probably used different mid-woofers, and probably wouldn't work well with different sized cabinets/PR's.

xenonsky

Thanks, I'll see how much they would cost to get them here in Hong Kong,
maybe I need to check with the local Polk distributor here and see.

I just picked up this vintage pair of Monitor 7 for $70 USD, and after much listening I found one of the tweeter sounded weak. I'm just trying to avoid putting too much money into it so that I maybe better off getting a pair of new RTi A5 or something similar.

comfortablycurt

NOOOOO!!!!


Those Monitor 7's are some awesome speakers...the A5's won't be an improvement over them in my humble opinion(not to down on the A5's though, as they are some excellent speakers).


What are your main uses with these M7's? Do you use them for 2 channel music listening or home theater? If you're using them for 2 channel listening...the M7's are some incredibly musical sounding speakers. You'd be hard pressed to find anything new for a similar price that's going to sound better. They'd sound MUCH better with the upgraded tweeters too.;)

I own a pair of Monitor 7A's, with Peerless tweeters, and I used to own a pair of RTi8's(older version of RTiA5). The M7's smoked them up and down for music listening. For home theater use, the RTi8's might have had a slight edge...but that's partially due to the fact that I was using a CSi5 center channel, which is timbre matched to the 8's, and not the M7's. As a multi-tasking HT/2 channel speaker...I'd definitely take the M7's.



For $70, you got a pretty good deal on those. Search the board for crossover modifications, and you'll be able to see what level you can take them to with a little love. My M7's are getting some XO mods this year.:)

xenonsky

I only listen to 2 channel music and occasionally watch movie with just two speakers. I love the sounds of my 5jr+ and that's I went for this pair of vintage M7 when I stumble across it, hoping for more room filling sounds and more bass in my living room about 15'x20' in size.

I'm wondering if my M7 is 7C or newer? how would I tell?

Does the crossover in the M7 age well, would they require replacement?

On thing I saw is the M7 black panel seem to have slight gaps at corners and some of bottom edges after years in humid weather here. At 1st I was worry about the cabinet would have leak due to this, but they sounded pretty good, except the right one seem a bit less loud overall and right tweeter sounded even less bright. However I love the lower end sound and rich room filling round from there M7 then 5jr+.

comfortablycurt

Yours have the SL2500 tweeters, which means that they're Monitor 7 Series II's. They were produced in the early 90's IIRC.

The M7's have surprisingly good bass, considering their size and design. They don't have as much bass output as my SDA 2A's, but the 7's do VERY well on their own. They should be a nice upgrade from your 5Jr+'s in that area.


Crossover components always wear out over time...and the XO's in those 7's are pushing 20 years old.

Part of how Polk kept the cost of the Monitor series down, was the fact that they used cheaper/lower quality components in the crossovers. Many people have upgraded their XO's with higher quality caps and resistors and had great results. I'm planning on upgrading the XO's in my Monitor 7A's this year.

xenonsky

When you say:

===
Polk has replacement tweeters available. They're a big upgrade over the stock tweeters as well. You can contact them at the number at the top of this screen. Mention that you're a Club Polk member for a discount.
===

Do you mean replacement tweeter of the same SL2500 tweeter, except newer? or better tweeter that can go into M7 with different newer model?

I assume I would need to replace both tweeters and can't just replace one as to make them sound even?

kcoc321

Xenon,
Polk CS sells an upgraded replacement for the SL2500. It is called the RD0-198. They are smoother sounding (so I have read) And yes you would want to replace both of them.
Be sure that you tell them you are a Forum member.

comfortablycurt

xenonsky wrote: »

When you say:

===
Polk has replacement tweeters available. They're a big upgrade over the stock tweeters as well. You can contact them at the number at the top of this screen. Mention that you're a Club Polk member for a discount.
===

Do you mean replacement tweeter of the same SL2500 tweeter, except newer? or better tweeter that can go into M7 with different newer model?

I assume I would need to replace both tweeters and can't just replace one as to make them sound even?

Whoops...I forgot to mention the model number.

kcoc321 wrote: »

Xenon,
Polk CS sells an upgraded replacement for the SL2500. It is called the RD0-198. They are smoother sounding (so I have read) And yes you would want to replace both of them.
Be sure that you tell them you are a Forum member.

^^^That^^^

xenonsky

Thanks everyone great comment and help with my questions.
I just swapped the tweeters on the Monitor 7 and the problem followed the tweeter to the other side. So now it's the other side that sounded less loud overall all. I suppose the tweeter create a very important overall imaging or sound perception.

I just called the Polk Audio distributor here in Hong Kong and they told me this is a problem likely due to the fluid in the tweeter dissipated over time which seems to be a common problem. Still waiting for a call back on price and replacement availability. And they told me probably won't be able to get me any replacement tweeter that didn't come originally with my M7 due to crossover difference.

Based on what they're saying , any problem with the Monitor 7 crossover with newer RD0-198?

By the way I saw on the back on my SL2500 tweeters with stampe QC passed on 1991.

F1nut

And they told me probably won't be able to get me any replacement tweeter that didn't come originally with my M7 due to crossover difference.

Based on what they're saying , any problem with the Monitor 7 crossover with newer RD0-198?

The only tweeter they will be able get is the RD0198-1 as the SL2500 hasn't been made in many years. You will have no problem with the new tweeters and the crossovers.

BTW, the new tweeters will take about 48 hours to break in, so don't judge them right away.

xenonsky

Thanks for the info. I originally had hope to be able to take the SL2000 tweeters from my 5jr+ and put in the M7s, but look I'll have to get the new RD0198-1.

But if I do try to drop in the SL2000 tweeters into the M7s, would it damage or cause problem for the crossover or tweeter?

kcoc321

No, probally not...just sound like CACA.

If it a $$ issue, you could watch for a SL2500 here, but you would be better off saving for the RDO's.
The SL2500's still go for $25-30, even used, when they do come up here...

here is a SL2500 on eBay for $35 BIN plus $14 shipping so that's the same cost as a RDO-198 from Polk, with the club discount.

http://cgi.ebay.com/One-Polk-Audio-5jr-SL2500-Sl-2500-Tweeter-Speaker_W0QQitemZ390160654640QQcmdZViewItemQQptZSpeakers_Subwoofers?hash=item5ad7632130

HB27

While you're at it...I'd replace the Polyswitches in the crossovers. Just pennies, easy install IF you have a basic familiarity with the soldering iron, and protect the tweeters and help with sound quality also.
Harry

xenonsky

I suppose the one with copper wiring from this is the polyswitch then?

http://cgi.ebay.com/Polk-Audio-Monitor-7-10-Crossover-Input-Panel_W0QQitemZ110497301017QQcmdZViewItemQQptZSpeakers_Subwoofers?hash=item19ba270219

xenonsky

actually I just took a few pictures of my monitor 7 crossover here and it looks exactly like the diagram of this:
http://www.polkaudio.com/forums/attachment.php?attachmentid=18774&d=1155784729

I appears that I don't have a polyswitch it seems, just 3 caps, 1 resistor, and the coil on the PCB. I guess I can replace them all except the coil on pcb.

kcoc321

Actually the black one is the small inductor for the tweeter circuit, which most ppl don't bother replacing either.

F1nut

I appears that I don't have a polyswitch it seems, just 3 caps, 1 resistor, and the coil on the PCB. I guess I can replace them all except the coil on pcb.

You got it.

xenonsky

I just called Polk customer service and was told that the replace tweeter RD0198-1 is the part number for SL2500 tweeters. I was under the impression that they're different tweeters.

The local Polk distributer here told me they have two SL2500 tweeters in stock for about $60 USD and I just wanna make sure I'm buying new tweeters rather than ones that've been sitting in back warehouse for years (or would tweeter have shelf life that's affected by temperatures or humidity ?)

anton.chigurh

Go for the RDOs.

kcoc321

xenonsky wrote: »

I just called Polk customer service and was told that the replace tweeter RD0198-1 is the part number for SL2500 tweeters. I was under the impression that they're different tweeters.

The local Polk distributer here told me they have two SL2500 tweeters in stock for about $60 USD and I just wanna make sure I'm buying new tweeters rather than ones that've been sitting in back warehouse for years (or would tweeter have shelf life that's affected by temperatures or humidity ?)

That is the "retail pricing" did you tell him you are a emember of Club Polk Forum? They are usually $48 inc shipping, unless Canada doesn' do that.

xenonsky

I guess I just wanted to make sure RD0198-1 = SL2500 tweeters (as mention by Polk CS on the phone) and it's the same tweeter and not different tweeters then?

The Polk distributor here in Hong Kong wanted $60 USD for each, I'll see if they'll give me any discount being a member of Club Polk Forum.

kcoc321

Yes, the RDO-198 is the direct replacement for the SL2500. And sorry, for some reason I thought you were in Canada. I don't know about HK distributors matching the US discount. Hope so, Good luck

xenonsky

I put the SL2000 from my 5jr+ into the M7 and they sounded great. I guess I'm used to the sound of the SL2000 from listening years with my 5jr+ as it doesn't sound too bright to my ears.

Thanks for all the comments, I'll see about replacing the caps on the crossover in coming months.