Should I or Should I not?

pauldsteve · November 2016

I have owned since new a set of Polk SDA 1A's, Serial no. 1920 & 1921, that I am just starting to learn about upgrading. I just joined the forum and all the information I see is several years old. I have already purchased (4) RDO-194-1 tweeters. However, in some of the information I have read where some people suggest disconnecting the Dimensional Tweeter and leave it disconnected altogether. Others never mention it. What is the best to do? I have always liked the sound the SDA-1A's have give me as they are stock but the left channel has developed a POP at high volume so I am going to start troubleshooting and doing all the upgrading at the same time. Thank you for any feedback.

crashb4 · November 2016

Disconnected mine and haven't looked back. It's the right thing to do.

pkquat · November 2016

pauldsteve wrote: »

This whole thing started because of the popping in the left channel at extreme volumes, (i.e. Explosions and Car Wrecks in Movies).

Press the passive radiator in a little bit, and watch the other midwoofers They should take 2-3 seconds to resettle. Compare the left and the right to see how long each stay out. If the left channel channel doesn't stay out as long, you likely have an air leak somewhere. Often the gaskets around the speaker frame can leak, and even the cabinet itself can leak. Some screws may need to be snugged a little, but don't really crank on them. You can strip them from the wood, or bend the frame. Also check for any cracking or tears in the surrounds, the rubber that holds the cone the the basket. It is more likely to happen to the passive. Check the spiders on the left midwoofers as well.

http://www.simplyspeakers.com/assets/images/Diagrams/Speaker-Cross-Section.jpg

Lastly get a good subwoofer. Let the sub handle the LFE from movies. The SDA's do a good job with bass, but not the super low frequencies in some movies. Whether it is related or not, the amp is probably clipping at those volumes. You may not hear it on the bottom end, but the high end probably is. With movies it is often only a short peak, so it is harder to pick out vs. listening to music.

Nightfall · November 2016

Thanks for the actual laugh I just had there when I saw that picture, that's funny stuff.

You need to get either Larry's rings or hurricane nuts to replace the stripped screws.

F1nut · November 2016

Disconnect.

Popping noise usually means one or more of the mid-drivers is failing.

boston1450 · November 2016

Gotta ask - what you are powering them with ?

pauldsteve · November 2016

F1Nut, all of the driver's ohm out and check out visually to be good. I am going to perform the mods to the drivers that have been called out by westmassguy. I had a bad tweeter which I am about to replace. Boston1450, I am presently powering them with a 9 year old Denon AVR-2308CI. It has worked great until about 10 months ago. Crashb4, thank you for that comment on the dimensional tweeters. I am thinking I need to send two of the RDO-194-1's back and just replace the two main ones and do not use the dimensional ones at all as advised by westmassguy and you. This whole thing started because of the popping in the left channel at extreme volumes, (i.e. Explosions and Car Wrecks in Movies).

F1nut · November 2016

Mods to the drivers? If you mean adding Dynamat Xtreme, a mod I came up with, that isn't going to help with the popping.

Swap the drivers out of the left speaker one by one with the right speaker until you find the one that pops. Then replace it with a new driver.

pauldsteve · November 2016

F1nut, That is a good idea. Thank you, I think I will try that. I am going to do the Dynamat Xtreme and the glued Magnet mod with the Loctite when I start doing those things. I will probably go ahead and do the Hurricane nut and machine screw mod also. Since all of those are not that expensive. Boston1450, my AV Receiver that I have used since September of 2007 to fire these things is rated at 170W into 4 Ohms, Dynamic Power. Since I have not determined where my Pop problem is if I cannot put my finger on it I may just sell the speakers as is and buy me a newer more efficient set of Front Mains. 95% of what I do now in my old age is listen to my 7.1 Surround System.

F1nut · November 2016

pauldsteve wrote: »

F1nut, That is a good idea. Thank you, I think I will try that. I am going to do the Dynamat Xtreme and the glued Magnet mod with the Loctite when I start doing those things. I will probably go ahead and do the Hurricane nut and machine screw mod also. Since all of those are not that expensive. Boston1450, my AV Receiver that I have used since September of 2007 to fire these things is rated at 170W into 4 Ohms, Dynamic Power. Since I have not determined where my Pop problem is if I cannot put my finger on it I may just sell the speakers as is and buy me a newer more efficient set of Front Mains. 95% of what I do now in my old age is listen to my 7.1 Surround System.

Ah yes, the magnet glue ups someone started years ago with JB Weld, then WMG came up with the Loctite idea, which works a lot better.

Forget that Dynamic power rating.

WTS · November 2016

pauldsteve wrote: »

F1Nut, all of the driver's ohm out and check out visually to be good. I am going to perform the mods to the drivers that have been called out by westmassguy. I had a bad tweeter which I am about to replace. Boston1450, I am presently powering them with a 9 year old Denon AVR-2308CI. It has worked great until about 10 months ago. Crashb4, thank you for that comment on the dimensional tweeters. I am thinking I need to send two of the RDO-194-1's back and just replace the two main ones and do not use the dimensional ones at all as advised by westmassguy and you. This whole thing started because of the popping in the left channel at extreme volumes, (i.e. Explosions and Car Wrecks in Movies).

One thing to ponder: you do want to fillet the drivers, but only if the magnets are in proper position. You do not want to glue any magnet that has shifted; you want to have it repaired first if possible, or replace it if not.

Is the popping from a problem driver, or was the amp clipping, or something else?

K_M · November 2016

I would think (not owning this exact polk , but bigger and small versions with more and less woofers) there is only so much you can expect with (4) 6.5" woofers, in a large box.

Home theatre and really loud deep bass, its hard to get loud volume, And Really deep bass at the same time, with limited drivers size.

4-6.5" woofers is really about close in area to 2- 8" woofers, and asking them to play really loud and deep may be more than they can handle.

We used to own some old advent Legacy speakers with the 10" woofer and acoustic suspension, that could really take loud and deep bass, a lot better than our similar sized polks from that era could.

The polks would go a bit deeper for sure, but would hit the limits, excursion wise far easier, on certain sounds or music.

1812 overture was one.

WTS · November 2016

If you're seriously considering buying new speakers, check out the Polk website this week, the sooner the better. The LSiM speakers are on 50% off sale.

pauldsteve · November 2016

pkquat, I did the pushing on the passive radiator thing upon advice from a Polk Tech. They said it should take from 3 to 5 seconds for the drivers to recover. I held mine for 10 seconds and no appreciable movement. On either speaker. So I think I have good air seal. The Spiders I will examine with a magnifier when I pull the drivers to modify them. Thanks for the heads up. I did not mention it but I have a Vintage Velodyne ULD-18 Series II that I am running with the 400W power amp that it comes with at 70% power. The Denon AV Receiver, does not have a Right and Left Channel Subwoofer Preamp out as the Power Amp wants. The AV Receiver only has one RCA Jack Preamp output for a Subwoofer so you have to run it in LFE+Main cable setting (in the programming) with one RCA cable put in the Right Channel input on the Subwoofer Amp. It has a speaker response of 18 to 85Hz. I have thundering, picture shaking, window moving bass. That is not a problem. Right now I have the frequency Crossover as broad as it can go for the two SDA-1A mains. Do you think I need to roll that lower end of that up above or barely overlapping the 85Hz of the Subwoofer? Do you think that might help the popping?

pauldsteve · November 2016

pkquat, I thought about it and I went and reprogrammed the Receiver to have a rollover frequency of 80Hz on the Subwoofer. We will see if that helps the Popping problem tonight at movie time. Everyone has had such great suggestions and advice.

pitdogg2 · November 2016

That receiver cannot power them enough they like gobs of it. I'll bet a good penny that is a clipping sound you hear as you stated "high volume" your going to start toasting tweeters better keep the spares.

trust me I have the same SDA's

K_M · November 2016

"the left channel has developed a POP at high volume"

It did not make the sound under the same circumstances before?

Narrow down where the sound is coming from. Not sure a tweeter would make a popping sound, usually they buzz or distort, or just quit.

Does it sound like over excursion of a woofer?

F1nut · November 2016

10 seconds? You've done something wrong or have something very wrong.

leftwinger57 · November 2016

If you had no response to a ten second hold then let go then something like F-1said is Very wrong. You might have a air leak from the cabinet seams, terminal cups. i/c connector, backs not to mention those drivers. I hope you didn't push in the passive to hard. My guess it's a clipping problem and your AVR isn't enough to handle the Polks. Thinking out loud here.--Is there an instructional video on You-Tube w/ vintage Polk SDA speakers ?

pauldsteve · November 2016

Leftwinger57, trust me I am very gentle with the Passive Radiators because I have read so many horror stories about how hard they are to repair or replace. When I push the passive radiator in maybe .75 of an inch you see the (4) Drivers push out together. I can count 1000, 1001.......etc. and I can guarantee that I do not see movement in those drivers in less than it takes to get to 1009. Are all of you guys saying that is wrong? I have not timed it to see how long it would take for them to get back to normal but I believe it is in excess of 10 seconds. I was told as long as they hold for 3 to 5 I am good to go. No one said anything about if it was too much longer something is wrong. Also if I move the radiator the (4) drivers move in unison the opposite direction of the Passive Radiator. On both speakers.

F1nut · November 2016

No one said because no one has had their drivers hang out for longer than 5 seconds.

pauldsteve · November 2016

pittdog2I realize that I need to upgrade to a bigger receiver or amp now. However, they gave me ideal service with this amp since September of 2007 and did not start acting up until March of 2016. 8.5 years that AV Receiver did all I ever wanted it to do and more. It might not have been "ideal" for the SDA's or the Denon Receiver, but I could turn it up loud enough with AC/DC you had to scream to say please turn it down, I am suffering above 98db ear damage. And Surround Sound was awesome. When the Enterprise flew over between the SDA's and the Velodyne it would literally rumble your chest and seat, from one corner of the room to the opposite back corner. Then the dreaded POP started in March. Sounds like you are taking the speaker leads across a 12-volt battery. If I turn the volume down to what most people would call normal house volume, still way louder than most ladies will let you keep it, I have no problems. I think it is the receiver also. But how do you make sure when you have no other speakers to try for mains? I guess I could send the damn thing off to Denon. Suggestions?

machone · November 2016

I have 1A's, disconnected the SDA tweeters and never looked back.

pauldsteve · November 2016

Thank you so much all of you for your insights. I will keep the group filled in on what I find and the end result of this conundrum. Please go Vote.

pkquat · November 2016

pauldsteve wrote: »

The Denon AV Receiver, does not have a Right and Left Channel Subwoofer Preamp out as the Power Amp wants. The AV Receiver only has one RCA Jack Preamp output for a Subwoofer so you have to run it in LFE+Main cable setting (in the programming) with one RCA cable put in the Right Channel input on the Subwoofer Amp.

pkquat, I thought about it and I went and reprogrammed the Receiver to have a rollover frequency of 80Hz on the Subwoofer. We will see if that helps the Popping problem tonight at movie time. Everyone has had such great suggestions and advice.

I'm not sure how your system is hooked up. If you have an external amp you can use the AVR as a pre-amp, send L+R (LFE+MAIN, Large) to the Velodyne and use it as the crossover. The Velodyne will send the higher frequencies to the amp driving the mains. Otherwise, I am not 100% positive on this, but I think you can 1) send just the LFE/Sub signal from the AVR to either the right or left channel of the Velodyne amp, or 2) use a splitter from the single LFE/Sub to both the left and right channels. Then you will be using your AVR as the crossover, and either using the AVR to power the mains or L+R rca cables to the amp driving the mains.

For the latter setup , you probably need to set your mains to "Small" to have them crossover at 80Hz. I don't know that AVR specifically, but most keep the mains at full range if they are set to large. Or try leaving them "large" but send only the LFE to the sub.

There needs to be a video of the push test. Air is designed to leak / pass through the center dust cone, but at a certain rate. That is where the 2-3, 3-5 seconds comes in. The speaker(s) need to move out when the passive radiator is pressed in and then slowly return to their normal position in X seconds while the passive radiator held pressed in. Once the passive radiator is released, the speaker cones get sucked in and then slowly return to their normal position in about the same amount of time.

K_M · November 2016

leftwinger57 wrote: »

If you had no response to a ten second hold then let go then something like F-1said is Very wrong. You might have a air leak from the cabinet seams, terminal cups. i/c connector, backs not to mention those drivers. I hope you didn't push in the passive to hard. My guess it's a clipping problem and your AVR isn't enough to handle the Polks. Thinking out loud here.--Is there an instructional video on You-Tube w/ vintage Polk SDA speakers ?

I think the OP was saying the drivers do not move BACK within 10 seconds, meaning they are very well sealed, albeit, better than any in the forum have experienced.

As to the AVR, he said he used it for over 8 years with no issues, using it the same exact way, and he is using a sub for the deep bass.
Yes I suppose it could be clipping, but he said he has used it this same way for a long time in the past, with no issues.....we will get to the bottom of this eventually!

westmassguy · November 2016

I'll chime in here, since I've been involved from the start. What Paul hasn't mentioned, is that he was operating the 1As without the Interconnect. He's now planning to set them up, as designed, with the IC in place. This will substantially affect the overall impedance of the speakers, and will present a much more difficult load for the Receiver.

pitdogg2 · November 2016

westmassguy wrote: »

I'll chime in here, since I've been involved from the start. What Paul hasn't mentioned, is that he was operating the 1As without the Interconnect. He's now planning to set them up, as designed, with the IC in place. This will substantially affect the overall impedance of the speakers, and will present a much more difficult load for the Receiver.

and now we have the rest of the story. Agree once that IC is in play he will see a big difference with that receiver. My old Yamaha receiver was a very stout receiver yet it couldn't hold up the the SDA2a set let alone the SDA1A's. I wonder if the popping was the unused speaker going past max excursion during his high volume?

westmassguy · November 2016

pitdogg2 wrote: »

westmassguy wrote: »

I'll chime in here, since I've been involved from the start. What Paul hasn't mentioned, is that he was operating the 1As without the Interconnect. He's now planning to set them up, as designed, with the IC in place. This will substantially affect the overall impedance of the speakers, and will present a much more difficult load for the Receiver.

and now we have the rest of the story. Agree once that IC is in play he will see a big difference with that receiver. My old Yamaha receiver was a very stout receiver yet it couldn't hold up the the SDA2a set let alone the SDA1A's. I wonder if the popping was the unused speaker going past max excursion during his high volume?

That could be the answer. Three stereo woofers producing bass frequencies, and one dimensional woofer flapping in the breeze

pitdogg2 · November 2016

westmassguy wrote: »

pitdogg2 wrote: »

westmassguy wrote: »

I'll chime in here, since I've been involved from the start. What Paul hasn't mentioned, is that he was operating the 1As without the Interconnect. He's now planning to set them up, as designed, with the IC in place. This will substantially affect the overall impedance of the speakers, and will present a much more difficult load for the Receiver.

and now we have the rest of the story. Agree once that IC is in play he will see a big difference with that receiver. My old Yamaha receiver was a very stout receiver yet it couldn't hold up the the SDA2a set let alone the SDA1A's. I wonder if the popping was the unused speaker going past max excursion during his high volume?

That could be the answer. Three stereo woofers producing bass frequencies, and one dimensional woofer flapping in the breeze

That was my thought.

pauldsteve · November 2016

Westmasguy, pittdog2, For the rest of the story, the first 11 months of this Denon AVR 2301CI receivers life it fired a 5.1 surround system with the SDA-1A's in their standard configuration including IC cable. I lived in an Apartment Complex and I did not dare turn the thing up to the Movie Theatre levels I do now. In August 2008 I moved to the house I live in now. I mounted the SDA's on the wall and did not run the IC cable. So from August 2008 until March of 2016 that receiver ran a 7.1 sound system with more efficient Surrounds (Klipsch Reference Series) and the SDA-1A's as the Front Mains not running the Dimensional effect. They were fantastic. People were so amazed at how fine the System sounded watching movies. Now the left speaker has the loud POP and after realizing the horror I had created to purist such as everyone on this forum, by mounting the speakers on the wall horizontally and not running the IC cable I am today pulling the speakers off the wall and going to stand them back up on the floor and reconnect the IC cable. I have made the decision to replace the main tweeters with the newest tweeters RDO-194-1's and disconnect the dimensional tweeters from inside the cabinet as the very first mod. All (4) drivers ought to work now if I am understanding things right. Then we will see what misery I have created. I do notice a big difference in sound setting the Velodyne Subwoofer crossover to 80Hz on the Receiver as pkquat hinted at. That took the bass out of the SDA-1A's. More to come. It is getting to be an experiment for sure. I will keep everyone filled in. Thank you all for your insights. Please vote today.

pitdogg2 · November 2016

pauldsteve wrote: »

I mounted the SDA's on the wall horizontally

it is now time to turn in your Polk Card

those tweeters may need to be fitted unless your had the SL2000 tweeters. Do you have fuses on the back? if so just pull the fuse for the Dimensional, if not be sure to tape the ends of the quick connects.

just start checking the spiders and voice coils on the 6.5"MW drivers

Should I or Should I not?

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