Ar9 lower mid pop needs help

[Guest Pacer]

I have a refurbished pair of AR9 with new capacitors and surrounds but have a popping sound in one lower mid at moderate volume. I do not want to damage the lower mid as it appears to look good. Perhaps the previous owner did not correctly replace the capacitor for this speaker. Asking for troubleshooting help to diagnose and fix this. I have read 100's of posts here and recently joined as a member. Have a pair of AR Holographic Imaging M 4.5 speakers and an AR cd-06 player also. Thanks for any responses. Pacer

[Carlspeak]

Have you tried stroking the mid by hand to see if it bottoms agains the back plate? If so, it may be suffering form spider sag putting the back of the VC closer to the back plate than normal.

[Guest Pacer]

I have a refurbished pair of AR9 with new capacitors and surrounds but have a popping sound in one lower mid at moderate volume. I do not want to damage the lower mid as it appears to look good. Perhaps the previous owner did not correctly replace the capacitor for this speaker. Asking for troubleshooting help to diagnose and fix this. I have read 100's of posts here and recently joined as a member. Have a pair of AR Holographic Imaging M 4.5 speakers and an AR cd-06 player also. Thanks for any responses. Pacer

Thanks for the reply. When I removed and examined the speaker a 1 inch place on the surround had come unglued and was (open air). I understand this to be a killer in a sealed box suspension system and have re glued it and will test it when the glue dries. Spider appears fine with no cone bottoming upon examination by hand with speaker removed. I think I will also add an additional layer of "rope caulk" to ensure the seal. Pacer

[soundminded]

I have a refurbished pair of AR9 with new capacitors and surrounds but have a popping sound in one lower mid at moderate volume. I do not want to damage the lower mid as it appears to look good. Perhaps the previous owner did not correctly replace the capacitor for this speaker. Asking for troubleshooting help to diagnose and fix this. I have read 100's of posts here and recently joined as a member. Have a pair of AR Holographic Imaging M 4.5 speakers and an AR cd-06 player also. Thanks for any responses. Pacer

Assuming that you have isolated the problem to the loudspeaker and it is not an amplifier or other problem IMO the most likely cause is that one of the new replacement capacitors is defective. What is most likely happening is that when the voltage across the defective capacitor reaches a certain point, the dielectric is breaking down and it is shorting internally. This will not likely show up on most capacitor checkers because the checker does not charge the capacitor to a high enough voltage to cause this to happen. If the problem is in the 80 microfarad series capacitor, when it breaks down the speaker will see the full low frequency output of the amplifier and could be damaged if overdriven. If it is the 30 microfarad shunt capacitor, the output of the amplifier will be loaded across the 263 milihenry choke and will be momentarily shorted. Either problem should be fixed immediately to avoid damage to the driver or amplifier.

I also have a slight opening in one of the 8" lower midrange surrounds on one of my AR9s. It will eventually have to be repaired with a new surround but appears now to have no effect on the sound. The back of the drivers on the front of the speaker do not affect the air tight woofer subenclosure. That is an entirely separate cabinet.

In my experience a popping sound is not characteristic of a damaged driver. Damaged drivers usually exhibit distorted sound to one degree or another or don't operate at all. Good luck.

[Guest Pacer]

Thanks Soundminded for the reply. Upon examination and re glue of the surround it seems your comments regarding the capacitors are accurate,because the speaker still pops. Perhaps the previous owner missed a capacitor during replacement or installed a defective one as you suggested. I will read up on capacitor suppliers to buy from and installation tips and report back to this forum. In the meantime, these AR9's are not being driven hard. The AR community needs all the working woofers to stay working! Pacer

[Guest Pacer]

Well, The Lower mid has been disconnected for protection purposes and now the upper mid has a pop also at moderate volume and when the bass thumps. The capacitors have been replaced and the crossovers look like spaghetti. The Ar9 schematic does not help me here and it looks like many of the replacement capacitors have been coupled together. I tried amping the upper speakers and not the lower and the pop went away. But it comes back when the bass speakers are powered; even bi amped. Considering going to a local speaker shop for expert repairs. Hope they are experts! When fixed I plan a post on bi amping. Pacer.

[bitbandit]

You might find that to get the exact capacitor values needed, multiple capacitors have been added in parallel and series which may make it look more complicated than the schematic.

Soundminded is most likely correct in the diagnosis, but if it were me I think the cheapest option with the most likely chance of success would be to obtain all new capacitors as per the schematic, then remove all the old ones and rewire the crossover as per the schematic. I am assuming you are ok with working on the crossover, if not then obviously seek help with it, but if you do it yourself you know it is done correctly and you will have as near as possible original performance. From the tests you have done it sounds like the drivers themselves are ok.

If you do have to resort to paying for a repair, I'd take a printout of the schematic and ask for the speakers to be wired as per the schematic.

[soundminded]

You might find that to get the exact capacitor values needed, multiple capacitors have been added in parallel and series which may make it look more complicated than the schematic.

Soundminded is most likely correct in the diagnosis, but if it were me I think the cheapest option with the most likely chance of success would be to obtain all new capacitors as per the schematic, then remove all the old ones and rewire the crossover as per the schematic. I am assuming you are ok with working on the crossover, if not then obviously seek help with it, but if you do it yourself you know it is done correctly and you will have as near as possible original performance. From the tests you have done it sounds like the drivers themselves are ok.

If you do have to resort to paying for a repair, I'd take a printout of the schematic and ask for the speakers to be wired as per the schematic.

bitbandit, at this point I have no idea what is causing this to happen. The fact that the midrange pops when the speakers are bi-amplified but doesn't when the woofers are disconnected rules out just about any plausible explanation I can think of. The only possibility remaining is that somehow there is an intermittent short circuit associated with the binding post connectors on the back of the cabint themselves, possibly between the woofer terminals. Other than that, I'm stumped.

[ar_pro]

Occam's Razor - the crossover has been "rebuilt", and it seems most likely to be the culprit, here.

You're going to need to go over the wiring & crossover components with the schematic in hand, and account for every connection.

Also, have there been any modifications that would involve the level control switches? Do they function properly? An intermittant switch might contibute to a "popping" noise.

Without being confident about the crossover, you can't be certain that the upper range drivers are not in danger.

[kkantor]

I guaranty, (Or your money back!), this is a clipping problem with your amplifier or preamplifier. Also, a bad crossover can cause the amp to clip. Try swapping the left and right speakers to the opposite amp outputs, and see if the problem follows the channel.

-k

Well, The Lower mid has been disconnected for protection purposes and now the upper mid has a pop also at moderate volume and when the bass thumps. The capacitors have been replaced and the crossovers look like spaghetti. The Ar9 schematic does not help me here and it looks like many of the replacement capacitors have been coupled together. I tried amping the upper speakers and not the lower and the pop went away. But it comes back when the bass speakers are powered; even bi amped. Considering going to a local speaker shop for expert repairs. Hope they are experts! When fixed I plan a post on bi amping. Pacer.

[bitbandit]

bitbandit, at this point I have no idea what is causing this to happen. The fact that the midrange pops when the speakers are bi-amplified but doesn't when the woofers are disconnected rules out just about any plausible explanation I can think of. The only possibility remaining is that somehow there is an intermittent short circuit associated with the binding post connectors on the back of the cabint themselves, possibly between the woofer terminals. Other than that, I'm stumped.

Yes, I agree. That's why I was suggesting getting back to a known point with the crossovers rebuilt and wired to the schematic. At the moment we have no idea what the crossover contains, or how it may be mis-wired. Even though it is thought to be bi-amped, a mis-wire may still have the the 2 circuits connected together in some way that would explain the problem, but we can't determine that without examing the wiring.

Ken's point is a good one - I had assumed, perhaps wrongly that the problem had been isolated to the one speaker.

[Guest Pacer]

I have switched the speakers as recommended and the pop is gone, even at loud volumes. However I can detect a little distortion in the upper mids on the problem channel. I cannot explain it. I am running a Tripath class T amplifier good for 325 WPC into 4 ohms. It is supposed to be more efficient than traditional class AB amps and yet the AR9's would consistently throw the circuit protection switch before I changed the speaker placement and now the amp is not being thrown off by the AR9's at loud volume. My thinking now is that another powerful amp is needed to correctly drive the 9's in bi amp mode. I read on Classic Speaker Pages that 400 WPC for the top and 400 for the bottom is optimal. Thanks so much for the helpful advice.

[ar_pro]

Ken was right, it's your amp.

The AR-9 separates the men from the boys, amplifier-wise, and it's not just about wattage ratings.

Owners posting on this forum have recommended Adcom, Crown, McIntosh and Yamaha, among others.

Big amplifiers with robust, stable power supplies.

[Robert_S]

If a "325 WPC into 4 ohms" Class-T Amplifier was operating correctly (and featured an appropriately highly-specified power supply unit), I would be confident in its ability to drive the AR-9 to significant output levels, without issue. (I'd guess you are using perhaps the TK2350, TA0105A or TA3020 [Truepath] chipset?)

I've been enjoying Tripath based amplifiers for years and had excellent results with low-power flavours, albeit at 'relatively' modest society-friendly volumes. For a while I used an EB-TA2022 (2x100W into 4 ohm) with some AR-90 but downsized to a TA2021B because I preferred the sound (and had no desire for day-to-day shake'n'quake-the-hood levels of bass!). Mostly when I'm listening to music, it's through AR-915, driven by the miniscule TA2024 or TA2020 (Charlize), and even these 'flea-powered' amps 'make some noise': they actually sound amazingly good. The energy efficiency of Class-T amplification is also a very attractive aspect. I digress.

If possible, try using a different (known to be working correctly) amplifier to firmly establish if the problem lies with the amp or the speaker. At present it sounds like your amp may be faulty—but this does not discount the use of (correctly operating) well designed and carefully constructed high-power Class-T amplification!

Robert_S

[kkantor]

I have switched the speakers as recommended and the pop is gone, even at loud volumes. However I can detect a little distortion in the upper mids on the problem channel. I cannot explain it. I am running a Tripath class T amplifier good for 325 WPC into 4 ohms. It is supposed to be more efficient than traditional class AB amps and yet the AR9's would consistently throw the circuit protection switch before I changed the speaker placement and now the amp is not being thrown off by the AR9's at loud volume. My thinking now is that another powerful amp is needed to correctly drive the 9's in bi amp mode. I read on Classic Speaker Pages that 400 WPC for the top and 400 for the bottom is optimal. Thanks so much for the helpful advice.

Great! You know, I've used the Tripath chips in a few commercial designs.... if they are used correctly, they can work extremely well. However, because of the high frequencies at which they operate, and because of their somewhat complex power supply requirements, they are a little bit fussy about their exact operating conditions. It might be worthwhile borrowing a different amp just to try, to see if your distortion problem goes away. (If not, there could be a residual problem in the speaker, or damage from the misbehaving amp.) For the test, you won't need anything near 400W. I recommend just using a friend's amp for a day, or borrowing one from a local music or hifi store. Once you have isolated the problem, then you will know where to put your $$$.

-k

[Guest Pacer]

Great! You know, I've used the Tripath chips in a few commercial designs.... if they are used correctly, they can work extremely well. However, because of the high frequencies at which they operate, and because of their somewhat complex power supply requirements, they are a little bit fussy about their exact operating conditions. It might be worthwhile borrowing a different amp just to try, to see if your distortion problem goes away. (If not, there could be a residual problem in the speaker, or damage from the misbehaving amp.) For the test, you won't need anything near 400W. I recommend just using a friend's amp for a day, or borrowing one from a local music or hifi store. Once you have isolated the problem, then you will know where to put your $$$.

-k

[Guest Pacer]

I have now bi amped the AR9's with a tri path amp at 325 watts (4 ohms) for the top and a old fashioned class A amp (400 watts at 4 ohms) for the bottom with success. This type of amping for these speakers has been recommended before on this site and I will verify the power needs of these speakers. The pop I initially wrote about was probably caused by lack of adequate power. Good luck to all. Pacer