My AR9's have me concerned

[smitty2k]

Noob here but still an enthusiast nonetheless.

Speakers in question: AR9 from the late 70s. 2 woofers, one low-mid, one upper-mid, one tweeter per cabinet.

I'll try to be brief. I'm in Virginia. My Dad is in Massachusetts. Dad says, "Son, I'm downsizing from a house to an apartment. You can have the AR9s but you need to ship and repair them."

I'm no fool. Not only is there significant sentimental value in these speakers but even after shipping and repair costs, they are/will be darn fine speakers at a great price.

What I've done:

-- Re-foamed all 4 woofers with surrounds I found on eBay.

-- Replaced the lower-mids with approved/blessed drivers I found on eBay. (Why replace instead of re-foam? Ummm I got lazy. Naturally I kept the old drivers.)

What they sound like:

-With the woofers unpowered, the mids and tweeters sound fine. (It seems like the crossovers are fine, but then again I wouldn't know what a marginal capacitor sounds like.)

-With the woofers powered, the bottom end sounds very rubber band like. Ugh. I tried to convince myself that this is what amazingly tight bass sounds like but they just aren't right.

--With classic rock bass they really sound like a kid plucking a rubber band "boing-oing-oing." Seemingly, you can hear the string vibrate.

--With male spoken voice dialog there's a staccato vibration in the bass notes that is "never" there in real life.

--With large orchestral organ music bass notes the woofers sound fine

--Mechanically, they "work" fine. But the sound is annoying when aiming for the true potential these speakers can deliver.

How I've diagnosed so far:

I have a $400 Yamaha AV amp with extensive pre-outs. At first I was biamping through a vintage Carver amp (thanks Dad) but the Carver seemed to be struggling (I'll skip the story there) and the woofers sounded rubber-bandy. OK, I took the Carver out and bi-amped using only the Yamaha. Still this odd twanginess sound.

OK, I don't have golden ears but I suspect anybody would hear this. Especially the spoken voice content.

Does anybody have a guess what's going on?

Thanks in advance,

Scott

[Gerry S]

I suspect the woofers. Perhaps the surrounds need closer scrutiny. I know you got them on ebay but can you identify the seller (maybe others here know the vendor)? Are the woofers seated tightly against the enclosure? Are the surrounds centered/glued tightly? Is this weird sound occuring on both channels at once? Try listening to one channel, than the other.

[xpat]

Hi Smitty 2K,

I have a pair of AR9s. I don't know what can be causing your speakers to sound that way.

I agree with Gerry S that you should take a hard look at the surrounds again. Also, are the cabinets air tight after removal / reinstallation of the drivers?

Another thought, is your Yamaha AV amp rated to drive 4 ohm loads and lower? (I believe that at certain frequencies the AR9s drop to 3.2 ohms.) Perhaps the amp is causing the issue (I've seen that many AV amps are rated only at 8 ohms - they aren't a suitable match for the AR9.)

xpat

[smitty2k]

THANKS for your replies! I'll give you some feedback as soon as I get a chance to carefully inspect and test.

BTW, the Carver amp that I tested at first with is 2 OHM stable so that may rule out the AV amp issue. But, thanks for the theory and I'll keep that in mind.

Do the big woofer caps ever go bad?

[rrcrain]

Here's an easy test to check if the cabinet is reasonably sealed. Very carefully, push in the cone on one woofer while watching the other woofer. If the cabinet is sealed, it wil move with the one you pushed. It may return to neutral...slowly.

[Mar]

Hi, just saw this topic. Not sure who the vendor was for your surrounds but you can find the exact ones you need by emailing Parts Express. They usually are very good and reasonable priced. Did you also replace the dustcap using shims. Many people that try their hands at foaming speakers watch a few of the shottier videos on Youtube where the fellow rips off the foam, scrapes it down and then slaps on the new foam without changing the dust covers. This can bring the speaker out of alignment and cause problems re: voice coil etc.

The cabinet not being air tight might also be a problem to consider. I would definately consider getting the foams and foaming the mids rather then using after market. There was/is a pair of AR9 for sale now currently which I posted some pictures on this site sent to a member by the vendor for his viewing. The individual (member here) sent them to me and I posted them for comments and concerns before purchase.

Some of the more AR savvy and knowledgeable members: (ARPro and SHOKDU - who just finished a top down restoration on his AR9 powering them with a pair of Monoblocks that you can see on his AR9 Restoration thread) made some very good concerns and comments; two of which were the non-original Midbass drivers and the woofers being foamed.

If you check into things above on this thread and still run into problems I recommend you contact the above mentioned members for their direct imput. They are VERY knowledgeable on this item.

Regards,

[SHOKDU]

When you replaced the foam, did you happen to replace the dustcaps as well?

When you replaced the foam, did you make sure the voice coil was level and not sagging downward, also not too far out as to be in "excursion"?

Have you ever heard voice coil rub before? Do you think this is a possibility?

When you pulled the drivers what did you re-seal the cabinet/speakers with?

I wouldn't start off by changing the woofer capacitors. Everything I've read and every bit of testing I've done on my old woofer capacitors points to the fact that they are very high quality, durable, and long life capacitors. Nobody has reported failures that I can find. This does not mean that they are commonly left in the speaker...seems some leave the old, and some replace with new (I replaced with new). Though some don't change the woofer capacitors, everybody that I can find has replaced the UMR/LMR/Tweeter capacitors...all with much improved results over original.

I have a feeling that your Yamaha AV receiver just doesnt have enough output for these speakers. It's more than a feeling though, I'm quite positive that you need a serious upgrade of an amplifier before you can really judge these speakers. It may be worthwhile to share the story behind why you think the Carver was struggling.

[soundminded]

First thing I'd do is make sure the woofers are sealed to the cabinet. When I had mine refoamed, I used Parts Express double sided tape specifically designed for this purpose. It seemed to work very well. I'd never use putty the way AR and others did. Then I'd remove the woofers and original LMRs and have someone who refoams drivers professionally take a good hard look at what you did. I'd verify that the replacement LMRs you used are the right drivers and that they work properly. If not, I'd chuck them. The metal can capacitors almost certainly do not need to be replaced. Replacing the other seven are a must. Failure to replace the old caps not only will distort the sound, it puts the UMR and tweeter in jeopardy of burnout, particularly the two caps wired in series. Use the correct value caps. There was a mistake in the schematic in the library. I went by the values printed on the original caps.

With a high quality 60 WPC amp my AR9s will produce very deep bass and show no distortion even when played very loud. I don't know what Carver amp you have or what receiver you're using but it takes an amplifier that is completely stable with very low impedance loads and that has a bandwidth extending to 20 hz or below to get the full potential out of these speakers. I'd bypass the A/V preamp and use a source such as a CD player with a volume control or a known good quality preamp. I'd also eliminate any clugey audiophile cables at least until you're satisfied that the speakers work properly (I had a lot of problems with a "gift" of brand M until I replaced them with some from the Dollar Store.) BTW, if the cabinets are not sealed and you overdrive the woofers, you could damage them.

Good Luck

[Gerry S]

It could be a combination of problems. You mentioned distortion on vocals. Are the replacement Lower Midrange drivers EXACT replacements electrically? If not, they may not roll off properly when coupled to the crossover network.

Sometimes, amplifiers can become unstable and go into oscillation.. "motor-boating". Like others here have mentioned, use a known "good" amp for troubleshooting. I'd go as far as having someone with the expertise and test equipment to go over your work. Something as complicated/refined as the AR9 warrants the added effort.

[djcheung]

Hi all,

I am a newbie here.

Just purchased a pair of AR9 and have some questions and wonder if anybody can help.

They are currently located in a small room.

I connected them to the small Denon AV amp AVR-1907.

On first audition, all drivers work but don't seem to be any bass.

All woofers are working and I have checked that they are air tight.

The foam surrounds were replaced by previous owner a few years ago.

They are not biwired or biamped.

I would like to know with all your experience on these speakers, what is the issue here.

I will evetually connect them to the Yamaha Z11 and hope it is just a matter of power.

By the way, I am located in th UK.

Best regards,

David.

[Gerry S]

Dear David (post #10)

If the bass is just weak and not distorted, sounds like SOMETHING is wired out of phase. I'd check wiring between left and right speakers (the easiest hook up mistake to make).

Then phasing between the two woofers of each AR9 (not likely if the internal connections are polarized).

If not a phasing issue, then speaker/listener placement and/or room properties can contribute to weak bass.

If bass lacks "whump" at loud listening levels (but ok at softer levels), then the amplifier is running out of power.

I'd check each of the above sequentially to isolate the reason.

[Steve F]

Also, the 9's are funny speakers. Because of their size and driver complement, it's natural to expect to be just overwhelmed by the bass during every listening session.

That's not going to happen. The 9's do indeed have deep bass response and handle a lot of power. But they are AR speakers, which means that they are exceedingly accurate. They will not deliver "false" bass if there is no bass in the program material to begin with.

I've had 2ax's, LST-2's, 11's, 3a's, etc. When I got my 9's and fired them up for the first time, I was......totally UNDERwhelmed.

"Where's the bass?"

It didn't seem out of the ordinary to me. I, too, wondered if something was "wrong."

But then, without warning a particular pop track came through with truly subterranean bass, bass I'd never heard or felt before, bass that seemed to shake the very structure of the house itself. Then, just as quickly, it was gone. The "normal" bass line in the song was there, nicely solid, but nothing more than what the 2ax might sound like.

So be careful of unrealistic expectations. The 2ax goes nicely to the mid-40's. The 3a/11 goes nicely to the mid-30's. The 9 goes nicely to the mid-20's. Very little program material will show up that difference, and the 9 shouldn't sound much different than the 2ax (on bass) if the program material only extends to 52 or 47 Hz.

Accuracy has its good points and its cautionary points.

Your 9"s may have an issue, so check them as Gerry recommends. But they may be performing perfectly normally. And a low-powered amp would not be absent of all bass, not at moderate levels. The 9's are more efficient than the 3a.

Steve F.

[djcheung]

Thanks Gerry and Steve,

I will go through the steps to illiminate the 'issues'.

I also have a pair of M4 and 94. I maybe wrong to compare the sound of these speakers to the 9's.

The smaller ones sound better with the same tracks than the 9's.

But saying that, it maybe the fact that there isn't enough room for the 9's to breathe properly.

If I go to a different room, I can feel/hear more bass.

After going through the steps later this evening, I will try a few films and see if there is anything different.

Best regards,

David.

[djcheung]

Hi all,

Tried connecting only the top drivers leaving the bottom woofers disconnected.

Don't seem to get much bass.

Checked all the connections and they are phasing correctly.

I have tried connecting one speaker at a time to illiminate the possibility of phasing between the speakers, but not much bass.

When I play the same tracks through my M4 and 94s, they sound much better !!!!!

It feels like that the Lower Midrange although works but doesn't seem to produce much presence.

Should they behave like this?

I will try some more with speaker placement tonight.

Best regards,

David.

[HarryM]

Have you check the box behind the LMU to see if it's still solid and air tight. I've read a few times that these can be a problem.

I don't have 9's but I do have 90's which use all the same upper drivers but have 2 10" woofers instead of the 9's 12" woofers. As far as placement goes I've found the main things are, you need at least 8ft between them and at least 3ft from any side walls. I don't have them against a back wall but I still get very good bass out of them.

[djcheung]

Hi HarryM,

I did take the LMU out to check if the wiring was inphase.

They are, and the space is well packed with sound proofing material but I didn't check if it was air tight.

I will check it again tonight.

Best regards,

David.

[Gerry S]

David. The LMR should NOT produce "bass" (it is for the "Lower Mid Range"). However, if there is leaking from the LMR into the main woofer enclosures, this could reduce "mid-bass" output from the main 12" woofers.

What I would do (if possible) is this: drive ONLY the woofer section of a SINGLE speaker system using a single track of music containing bass. When doing this, place this speaker system into a marked location. Mark the listening postioning when doing your evaluation. Remember the settings of your electronics. Evaluate and remember the amount and "quality" of bass being reproduced for this listening/speaker location combinition.

Then take the OTHER speaker and place it in the SAME location as the first. Be sure to also use the same LISTENING location as for the first speaker. Also, be sure to use the same musical track, amplifier channel and electronic settings as for the first speaker. You should get virtually identical performance results from each speaker. If a noticible audible difference exist between the two systems, then at least one speaker system has "woofer issues".

It's also possible the woofer surrounds may have seperated from the cone (if the adhesive wasn't applied properly when refoamed). Or the woofers are not seated tightly against the cabinet. Either condition will reduce bass output.

[djcheung]

Hi all,

I have eventually got rid of the huge 36" Sony Widescreen CRT.

Do you know how difficult it was to give it away ! Nobody wanted it even the charity shops

It took four of us to get it in the car.

With the old TV out of the way, I have put the AR9 in the 'proper' location and WOW, I had to double check if the subwoofer was still connected. I have relocated the B&W PV1D to somewhere else.

They sound ok but the highs are not as good as the Holographic M4's.

Reading through the forums I will now go and change the capacitors in stages.

The first ones I will do is for the tweeter and the UMR.

I will be using the Clarity ESA caps. Are they OK?

When replacing these caps, is there anything I need to be aware of, eg. in terms of additional resistors to compensate the difference between the old and the new caps?

I do not have any sophisticated measuring equipment so cannot measure.

Any ideas?

Best regards,

David.