Muffled sound

[bluecomet]

I was wondering if anyone knows why a pair of speakers would at higher volumes become muffled and lower itself in volume. Does that mean it is the speaker crossover, speaker wire not able to handle the current or a problem with the receiver. Anyone ever experience this. This has happened twice with two different systems. The only thing in common is the speaker wire being a basic store bought 18 guage wire. The one receiver I am using is the Kenwood KR-9600. If I put the volume at 12 o'clock that is when the sond begins to become muffled. If I lower the volume the sound straightens out. The speakers are SDA 2B's. Thanks.

[leroyjr1]

I wouldn't run sda's off a receiver. Could be the receiver.

[bluecomet]

What would you run it off of?

[leroyjr1]

What would you run it off of?


External power amp. Common ground. I also have the SDA 2b's and not had that issue.

[Eric W]

I'm fairly certain that speaker has polyswitches which can wear out overtime and prematurely kick in (explains the tweeter level lowering, causing a more muffled sound quality). I'll check when I'm back in the office on Monday. We can provide replacement polyswitches which you can solder in.

[bluecomet]

Thanks Eric. That would be appreciated.

[Keiko]

Service with a smile. :) You guys Ro(k Eric!

[janmike]

Service with a smile. :) You guys Ro(k Eric!

And on a day off to boot. Talk about service.

[inspiredsports]

What would you run it off of?

What model receiver are you using?

It's hard to say for sure until your model is know, but the need to dial it up to 12 o'clock could indicate it is underpowered or not a "high current" design and it's definitely clipping (saturating its output transistors beyond its design specifications). SDA 2B's are a lower impedence speaker at just under 6 ohms and prefer clean power like all of the SDA designs. New polyswitches may help, but if it's a source (amp) issue they will only postpone your problem as polyswiches degrade each time they are tripped.

[WilliamM2]

At 2x160 watts (2x200 at 4 ohms), that Kenwood should power them fine. I would replace the polyswitches as Eric suggested.

[inspiredsports]

My apologies. I don't know how I missed the receiver model description in post #1. Yes, those specs should comfortably drive SDA 2B's unless there are problems with aging caps, etc.

There's one listed on eBay right now at http://cgi.ebay.com/Refurbished-Kenwood-KR-9060-Euro-Kr-9600-Rare_W0QQitemZ150319064142QQcmdZViewItemQQptZRecei vers_Tuners?hash=item150319064142&_trksid=p3286.c0.m14&_trkparms=72%3A1234|66%3A2|65%3A12|39%3A2|240%3A13 18

[george daniel]

tubed amplification for 2B's is the ticket. Just my .02 worth:)

[F1nut]

At 12 noon, that receiver is clipping and causing the poly's to kick in. Replacing them is a good idea, but Inspired is right, "they will only postpone your problem as polyswiches degrade each time they are tripped."

[bluecomet]

I have a feeling it is the polyswitches. I think the SDA 2B's are rated up to 250 watts. It should handle the Kenwood at half power. I think the tweeteres are going out at the twelve o'clock position, as soon as you drop it to 10' o clock it comes back. I upgraded these speakers to the new RDO's. Do all SDA's have polyswitches. I have two SDA SRS 2's, would they have them also.

[F1nut]

Blue, you have a lot to learn. The 12 noon position on the volume dial is not half power. In all likelyhood it's the point at which the amp in your receiver is running out of clean power.

You're also misundertsanding the relationship between the rated power handing of a pair of speakers and the rated power supplying it. You would be much better off having an amp at 500wpc driving the 250wpc rated speakers, than the other way around.

Bottom line, even with new poly's, turn it down or get a more powerful amp.

[Face]

When it comes to watts, it's quality over quantity.

[inspiredsports]

I've noticed through the years that few amps perform well past 11 o'clock, and that 12 is 100% into clipping territory. I'm amazed those 2B's were able to absorb the 12 o'clock setting from that receiver without more that the polys complaining.

[F1nut]

I can't argue with that Mike, but that's another discussion.

[bluecomet]

You are right I do have a lot to learn but that is why I am here. I don't understand why a receiver is maxed at the noon position. If the receiver volume can go up to 10 and the receiver starts to clip at 5 what is the point of 6 thru 10 on the receiver if it can't handle it. Is it in case you use an external amp, that the receiver turns into a pre amp and the 6 to 10 volume setting can then be used. I am trying to get the hang of this please bare with me.

[inspiredsports]

I don't think volume controls are linear, but are log stepped in some fashion or another, possibly to keep the left and right channel signals balanced within a tighter db range.

[F1nut]

Is it in case you use an external amp, that the receiver turns into a pre amp and the 6 to 10 volume setting can then be used.

No. You will still be limited to the useable power range.

[bluecomet]

So basically what you are saying is that when you begin to hear distortion or degraded sound at higher volume, the receiver has hit the wall. The receiver has basically red lined on the tach in car terms, no matter where it is on the volume control. Sorry, I am into muscle cars.

[F1nut]

You got it.

[reeltrouble1]

You got it.

sounds like you spent the night at HIE.......

Welcome to our world Blue and yes you got it, now your going to get it, keep us posted on your trip into the rabbit hole.

RT1

[bluecomet]

I am getting the hang of it. I played the SDA 2's on the Kenwood 9600 and paid close attention to the power meters. I can play these speakers at around 2 and half on a scale to 10 on the volume knob. When I had turned it to 12 o'clock no wonder why the polys tripped. At two and half maybe three it is really loud.