SDA-1C Right Channel No SDA Effect

pitdogg2

The passive should come right off no need for sharp tools or corners. Unless the gasket was torn by the last owner you'll be fine.

F1nut

Gaskets are paper thin, supposed to be that way. Unless torn reuse what you have. Amazing how some make mountains out of mole hills about it.

PolksTillIDie

Thanks for the gasket update.

Its funny, I don't see volume level listed with %THD specs and that seems to make all the difference in my measurements. I'll keep looking around for better references.

As for the microphone, I ended up using the built-in mic in my Dell laptop. I originally used a no-name cardoid mic I found on Amazon. Its claim to fame was it was sensitive from 20Hz to 20kHz, and it was, but it soon developed harmonics of its own and I found that the built-in mic could record the same freq range without any problems. I read somewhere that a mic you use for this kind of basic audio analysis doesn't have to be that advanced, just cover the 20Hz-20kHz range. That's why manufacturers of modern receivers and amps include those little cheap ones for auto-EQ that seem to work ... eh, somewhat.

Know anyone that has inside 1C pics?

Gardenstater

pitdogg2 wrote: »

The passive should come right off no need for sharp tools or corners. Unless the gasket was torn by the last owner you'll be fine.

He was concerned about it. In my experience they sometimes stick a little bit, to the baffle. No harm in using a tool to release the grip by getting underneath the edge and levering up (not to cut into the gasket!). The 5 in 1 tool has a thick blade with a bevel on it. Anything with a bevel on it would work, so as not to damage the gasket. If they don't stick they can just be lifted off with the fingertips.....goes without sayin'.

PolksTillIDie

Yeah, you tell 'em Gardenstater. If you'd had as much trouble as I've had just trying to get some sort of advice on what to do about the gasket from speaker repair shops, you might be concerned too, F1.

Actually, like I said the present ones were/are warped, with parts of it folded over on itself. All in the same places, in just the same way. I figured it was from the factory. I put them back on, but it wasn't optimal.

Now, if anyone had some pics, I could get started ...

Tony M

Clunking sound from inside your speaker is 1,000,000 times more important than a gasket or something for now.
That's my opinion after reading all this chart analysis's and gasket stuff.

Don't you own a Philips head screw driver? What, 6 screws to unscrew?

Why are you seeming to avoid looking behind that passive woofer? Show us a picture of what made those sounds. Please.

That would be my FIRST curious question/anomaly to investigate now that you heard it. Who knows what it is...I don't recall anybody having a loose anything in a SDA-1C before.

It might be some old owners secret $$$$ stash he/she put in a box years ago. Maybe gold coins!

pitdogg2

PolksTillIDie wrote: »

Yeah, you tell 'em Gardenstater. If you'd had as much trouble as I've had just trying to get some sort of advice on what to do about the gasket from speaker repair shops, you might be concerned too, F1.

Actually, like I said the present ones were/are warped, with parts of it folded over on itself. All in the same places, in just the same way. I figured it was from the factory. I put them back on, but it wasn't optimal.

Now, if anyone had some pics, I could get started ...

Sorry man but as timid as you seem to be in removing screws and needing pictures before you do so....

You're doomed....

Gardenstater

PolksTillIDie don't be dissuaded. I've been here a little over a year and there are a lot of fine people here. But you really do need to carefully begin that surgery on your SDA 1C. Everyting gonna be alright as Bob Marley says

[Deleted User]

Easy gentlemen...

PolksTillIDie

Hmmm. Looks like the last posts between F1 and me have been removed. So be it. From now on, I'll expect an emoji if you're kidding.

So back to the problems at hand.

No, I'm not squeamish about opening up my speakers. This discussion started about the SDA issue and morphed into tweeters and gaskets, and now back to the SDA issue. I didn't want to paint myself into a corner by taking out a driver/radiator in a way that needed another gasket that I couldn't get. Between two speaker repair shops I checked with, one didn't have any gaskets and the other had never heard of gaskets on speaker components. So much for commercial expertise. Its not like the speakers are inoperable now, they sound great, just no right-channel SDA.

So give me a bit and I'll get into that speaker, if for no other reason than to get your blood pressures under control. Just one more song ....

Jstas

Geebus, get over it already!

https://www.parts-express.com/Search.aspx?keyword=speaker gasket&sitesearch=true

PolksTillIDie

OK. Some obvious problems with some obvious solutions. Here ya go:



And a closer shot:



So two free wires both black, and two unused terminals, one sort of "clipped". A free-floating circuit board, pretty light for a "clunk", but everything else is fixed in position. Looks like the board had clips to secure it to the ah ... round thing with all the copper wire wrapped around it. Say, someone want to orient me to these parts?

On the circuit board, one wire is labelled "P" and the other "R". So which goes to which? Or can I get away with experimenting?

PolksTillIDie

Oh, and ah ... no gasket. Just pushed on one side and lifted other up with a thumbnail. I see clips that might hold the board onto the coil. Is that its normal place?

Gardenstater

That's the 16mH, 18awg inductor that the circuit board came unclipped from. Those clips may or may not be broken. I'm not sure. P goes to the negative binding post and one end of the jumper and the 20uF capacitor and the negative terminal of one of the stereo MW6511 drivers. R goes to the 40uF capacitor and the negative terminals of the MW6510 dimensional drivers and to the #2 terminal of the IC socket (the round pin). It's actually good that you discovered something wrong and that it seems like it is easy to fix!

Faustin

I have been following this thread for a couple of days and I can't believe it took this long for the op to pull the passive to see what the real problem is. Something clunking around inside a speaker is a huge red flag as to problems. Glad to see that you are on the right track.

PolksTillIDie

Uhhhh...okay.

So Faustin, you are excused. I didn't know you existed, much less were caused so much pain at my slowness.

So Gardenstater, thanks for the schematic. I'm a little confused. I have two loose black wires, which are labelled P and R on the crossover circuit board. I have nothing connected to the coil. It has 2 unused terminals, they don't go there? There are no terminals that fit those loose wires on the negative binding post, but they do fit the terminals of the coil. In the schematic, I see a P and R connected to the coil. Forgive my ignorance, electronics is not my thing...

michaeljhsda2

Someone removed the bolt from the rear of the speaker that holds the inductor (which the xover is attached to) in place and it crash landed at the bottom of the speaker. The 2 black wires from the crossover connect to the tabs on the inductor (doesn't matter which wire goes on each post). Change that....now that I look at it closer, the standoffs broke and the xover fell off. The inductor is where it should be, at least from what I can tell. Can you move the inductor or is it secure? If it moves look at the rear of the speaker, should be a hex head bolt there that secures the inductor to the back of the speaker.

PolksTillIDie

Thanks michaeljhsda2.

The inductor/coil is fixed/screwed to the rear wall of the enclosure. There are screw heads on the outside of the enclosures near the bottom of the enclosures. Probably an example of Polk manufacturing modifications on the fly. But, yeah, the wires going to the coil seems like the obvious answer. I was about to ask about the polarity of the connection, but you answered that. Here goes ...

pitdogg2

PolksTillIDie wrote: »

Oh, and ah ... no gasket. Just pushed on one side and lifted other up with a thumbnail. I see clips that might hold the board onto the coil. Is that its normal place?

Yes those stand offs should have a locking tab to clip into the holes on the board. The wires go on the spade tabs as @michaeljhsda2 stated. The bolt is still there and glued as it should be. You need to carefully look to see it the quick connect tabs on the inductor are able to be straightened without breaking. otherwise I don't think you'll be able to get the board to click back on to the standoffs check the standoffs to make sure all of the standoffs have the little locking tab still in place. to the best of my ability from what I can see in the picture it appears that they are. you should be able to see the holes in the board that those tabs go through pretty easily it doesn't matter which way the board sits on there as long as all the holes line up to the tabs. you definitely need some gasket on the passive or else it's going to leak it's a sealed enclosure it has to be sealed completely or you will not get bass out of it. once again I will recommend the armacell tape it's what I've used on passives before it's easy to work with you'll need to cut it down to the width of the passive flange flat back adhesive side of the tape to the passive not the box. if you ever need to take it off it will come right off even though the sticky part is on it don't worry about that chances are you'll never need to take it off. Last tip if you use in the armacell tape do not make a straight cut go all the way around the passive overlap a little bit onto the new side cut at a diagonal so therefore you don't have a hole so air can get through. Hope all this makes sense to you.

Have a great day.

pitdogg2

Let me just restate something here. If that big inductor is moving around then yes the bolt has been removed I seen the nut. I personally have never seen any of the inductors attached with screws. Maybe take a picture of the back of the box showing these screws. if the screws got into the wire and knock the coating off that could be a bigger problem as in it could Short circuit the inductor.
I don't think Polk did that simply because they would never have hot melted the nut in place to seal it up if they use the screws.
It does seem to me that do you have an open hole in the back of the cabinet if that's not using the bolt you need to make sure that's not there or that's one reason you get no bass.

PolksTillIDie

Updates and clarifications:

1) Still no right-channel SDA effect.
2) I misspoke, there was a thin adherent gasket on the passive radiator.
3) A bolt/screw holding the coil on was stock apparently, I found a pics of two online, both above and below (like mine) the binding posts.




4) The inductor/coil is fastened tight to the enclosure back.
5) I get amazing bass, strong down to 20 Hz, and weaker down to 10 Hz (unless that's some weird aliasing by Yamaha).
6) Doesn't seem there would have been enough force to pull off both wires. The wires still attached allow the board to rest on the bottom of the enclosure, so why were they off?

So, of course disappointed connecting the disconnected wires didn't change anything. What is the purpose of the coil anyway?

Any chance its a bad IC cord? Is it possible that a bad one could still produce one side SDA?

I'll try some more tests ...

pitdogg2

What is the purpose of the coil anyway?

Sub bass inductor. Allows bass to be reproduced by all four speakers in each cabinet.

Any chance its a bad IC cord? Is it possible that a bad one could still produce one side SDA?

No not in my experience

PolksTillIDie

Well, that's interesting. So at a given bass frequency, say 30 Hz, all the midwoofers should be active/playing?

Just checked. With a 30 Hz test tone:
Right channel, all mw play except right upper (dimensional)
Left channel, NO mw plays except lower right/inner (stereo)

Funny, I thought I had plenty of bass, and the Yamaha YPAO is always trying to turn down the volume of the right side. But it at least partially explains why no sda effect on right: no dimensional mw firing on left.

So the plot thickens. Gotta get some other stuff done tonight. My neighbors are probably plotting my death after loud playing all those test tones...

I'll check back in tomorrow.

Thanks.

txcoastal1

Get off the test tones and receiver calibration at this time
Use pure direct or 2 channel mode...Definition pends on receiver

SDA effects resides alone and you need to get these set up, repaired, etc correctly

Rooms will create their own anomalies of their own

PolksTillIDie

I used the test tones to be sure of a standard bass signal and feel if the mw were firing. The rest was commentary. See my earlier post on my assymetrical room acoustics. Yes, the SDA effect is exactly what I'm talking about here.

PolksTillIDie

So just to be clear, all the midwoofers (both stereo and dimensional, right and left channel) should be firing with that low bass tone (30 Hz)? The second stereo/dimensional mw doesn't kick in at a certain volume, for instance?

pitdogg2

All MW should be working IIRC @125hz and down with or without cable.

Agree get on with straight 2ch only.

PolksTillIDie

Yeah, the Yammy receiver I only use in straight 2 ch mode. Looks like I outta look inside the right speaker I guess.

What's an easy way I can discern whether its a given mw not working versus a problem with its wiring?

Thanks.

Tony M

Sorry there wasn't a box of $$$$ in there.

Is the balance knob on your receiver back to center now?

Gardenstater

PolksTillIDie wrote: »

What's an easy way I can discern whether its a given mw not working versus a problem with its wiring?

Thanks.

If you remove the wires for a given MW driver you can put a ohmmeter on it and measure its DC resistance and compare to specs or known good ones. Then if it passes that test you can take a 9V battery and momentarily touch it to the terminals and make sure that there is movement of the cone. This can test for proper polarity as well (usually there is a red dot near the positive terminal). That doesn't prove that there is absolutely nothing wrong but it will pinpoint a lot of failed drivers that don't just have a problem with voicecoil scraping, for example.

As far as the wiring goes, if it is a proven good driver and there is no sound coming from the speaker when it is wired to the crossover, then it pretty much indicates a problem with the crossover/wiring.