AR10pi

[Guest Rob]

Just a quick note here. I have only recently found this site when I decided to look up a bit more about my own speakers. AR10pi serial nos A09595 and A9597. I bought them 2nd hand around 1990 for $200.

Looking at all the messages here, they suffered with the usual "rot" and I was unable to locate new bass drivers here in UK. I was about to dump them and buy a new pair of speakers when my hi fi store said repair them. So I purchased a pair of Eminence Delta 12's and fitted them. Okay I had to cut the cabinet, but once in, they worked fine.

My amp is an Onkyo Integra A8500 which I think is under powered but does okayish in my living room. I would like eventually to upgrade the amp. Does anyone out there have any good recommendations, not too stiff on the wallet. I have read Yamaha do a good amp, but none of my friends are out of the "Technics / Kenwood" era, so no help there.

One thing is, I would not part with the Ar's now I know what I have!!

Rob

[tysontom]

>Looking at all the messages here, they suffered with the usual

>"rot" and I was unable to locate new bass drivers here in UK.

>I was about to dump them and buy a new pair of speakers when

>my hi fi store said repair them. So I purchased a pair of

>Eminence Delta 12's and fitted them. Okay I had to cut the

>cabinet, but once in, they worked fine.

Bob,

I think what your hi-fi store was trying to tell you was to repair the woofers that came with the AR-10Pi; i.e., replace the surrounds, rather than putting in strange, new woofers. Changing out the woofers altogether is risky because the Eminence speakers you retrofitted into the cabinet probably do not have the same characteristics as the original AR woofers, which were designed specifically and uniquely for that size and style AR cabinet. The interior volume, the amount of fiberglass padding, the crossover points, etc., all work together to make the original woofer perform properly with very low distortion, flat and accurate response.

In the end, if you could repair the original woofers with new surrounds -- and try to get them back into the AR-10Pi cabinet -- you would probably be happier.

--Tom Tyson

[tysontom]

>my hi fi store said repair them. So I purchased a pair of

>Eminence Delta 12's and fitted them. Okay I had to cut the

>cabinet, but once in, they worked fine.

http://www.usspeaker.com/Delta-12A-1.htm

Rob, this woofer (see link above), if it is the one you fitted to your AR-10Pi's, has a 55 Hz. resonance and is also an 8-ohm speaker. More importantly, it appears to be an instrument speaker, such as a guitar speaker or such, capable of high power but not necessarily low frequency. The resonance of the AR woofer you removed from the AR-10Pi has a resonance of somewhere between 14-18 Hz. Besides, the excursion capability of the Eminence is very restrictive, and it could not produce the very low bass you would expect from the AR woofer.

--Tom Tyson

[ar_pro]

Would it still be possible to re-fit the flat-sided AR woofers if the baffle's been routed to accept the Eminence frame, Tom? I'm afraid that if it's been cut into a complete circle, that might just be the ballgame for that cabinet.

[tysontom]

>

>Would it still be possible to re-fit the flat-sided AR woofers

>if the baffle's been routed to accept the Eminence frame, Tom?

>I'm afraid that if it's been cut into a complete circle, that

>might just be the ballgame for that cabinet.

You are right. Refitting the AR flat-sided woofers in the round hole would require major woodworking. Perhaps a better idea would be to find a pair of the NHT 3.3 woofers (NHT-1259 or something, I can't remember), and install them since there is now a true round hole. There would still be problems, but the deep bass would return, and then some.

--Tom Tyson

[Guest Nigel]

>

>Would it still be possible to re-fit the flat-sided AR woofers

>if the baffle's been routed to accept the Eminence frame, Tom?

>I'm afraid that if it's been cut into a complete circle, that

>might just be the ballgame for that cabinet.

If you have access to a scroll saw (like this one {url]http://www.harborfreight.com/cpi/ctaf/Disp...temnumber=41889) or band saw (like this one http://www.harborfreight.com/cpi/ctaf/Disp...temnumber=40981" target="_blank">http://www.harborfreight.com/cpi/ctaf/Disp...temnumber=40981 it should not be a big deal to make pieces to repair your cabinet. I would use MDF, glue it in with yellow wood glue and add a couple of screws (drill holes first) parallel the front face.

Regarding amplifiers; an Adcom 545, 545 II, 5400, 555, 555 II, or 5500 work very well with classic AR speakers, the 5400 and 5500 are current production. You want an amplifier that can handle high inductive loads and very low impedance. An Onkyo M504 is another good one.

[ar_pro]

From looking at the 10pi blueprint (ar10pisystemassymk1), doesn't it seem as if enlarging the hole to make a perfect circle would do structural damage to the cabinet, or is that just a cosmetic moulding at the sides?

Adcom really appears to be a good choice for AR speakers, providing substantial power, and excellent low frequency control...wasn't C. Victor Campos involved with both companies?

[Guest Bret]

>I'm afraid that if it's been cut into a complete circle, that might just be the ballgame for that cabinet.<

Maybe not. I couldn't do the repair myself, but I just did a little measuring and it looks like there is room to get a full circle without completely destroying the cabinet. Restoring it to it's original shape would be interesting, but I'd likely leave it to a pro.

Bret

[Guest Rob]

I had to cut the cabinet to fit the Eminence drivers. However, I still have the location screw holes for 4 of the screws(top and bottom 2) and I think to refit AR Drivers I would have to make some sort of section to fit in the sides to fill the gap. Not impossible!

I have looked over here in England to find NHT drivers and there doen't look to be any sources, altough no-one has come back to me with Yes or No.

Can anyone tell me how many AR10pi's were made between '77-'79?

As moine ar #9000 were 9000+ produced?

[Guest Rob]

Hi Tom

I am looking now for replacement woofers. I cannot seem to find NHT over here in England.

What should I be looking for?

Wattage - 400?

Ohms - 8 or 4 ohms

Freq got that 20hz ish

Thanks

Rob

[Guest Nigel]

>I am looking now for replacement woofers. I cannot seem to

>find NHT over here in England.

>

Rob;

Repair the cabinet, and re-install the refoamed originals. Anything else is a compromise.

[Guest SteveG]

Rob,

The advice to repair the cabinets and reinstall the original woofers is the only way to go. Now we are getting down to some fun stuff. Carpentry.

Sounds like what you have done is to cut out some of the "lip" that the woofer frame sits against and bolts to, perhaps all the way around. With a little care, some yellow carpenter's glue and a couple c-clamps you should be able to restore this.

Assuming the woofers install in your 10pi as they do in my 11's, what I would do is determine the thickness of the "lip" that supported woofer frame, and the thickness of the "indent" in the front panel that created the lip. First cut out a piece of plywood of the thickness of the lip just the size of the overall hole you have created. Then cut a flat sided hole in this just richt to provide the original lip for the woofer. Next cut another piece of plywood the thickness of the indent to the same size as the first piece. But in this cut a larger flat sided hole to match the outside of the woofer frame. Make sure these two pieces are on the same center and alignment. The relaining work is to cut another piece of plywood with a 1" greater outer radius all around than the first piece, but the same center cutout. This piece installs from the inside of the cabinet and is glued to the back of the front panel of the enclosure, with the other pieces glued over it one on the other. I would glue these all up at the same time with plenty od clampimng and overnight to dry. Note that the side to side width of the innermost piece you cut will be limited by the inner width of the cabinet so you can slip it into the exclosure theough the hole in one piece. Ill bet this will be plenty strong enough. if by chance it is not, you could install another ring that overlaps the outer face of the front panel to really overblild this, but that would detract from appearance, and possibly dispersion. I am guessing that the small amoutt of interior volume that will be filled by the inner most ring of plywood will not seriously affect volume and the operation of the woofer, but Tom or Ken can probably speak to that.

Too gbad we are an ocean apart, or I'd tell you to bring em over and we could glue em up together. Sure beats trying to rewind a tweeter (which I understand from Tom IS impossible).

Good luck

SteveG

[Guest Rob]

Hi Steve

Thanks for your good advice

The biggest problem I am having is finding a pair of woofers over here.

I have looked for the NHT1259 and AR woofers - no luck.

AR doesn't exist over here and any audio store says no way and cannot help.

I emailed Layne and they said couldn't help.

Only one place over here offered to help and they came up with a 12" woofer by Peerless - 831857, which they say they use for all the AR speakers they come across.

Specs as follows:

831857 polymer cone Bass(Reference #peer16)

89dB ~ 8 ohm ~ 315mm o/dia ~ 115mm deep ~ 39mm vc ~ 220w power ~

24Hz Fs ~ 20-1000Hz range

Keep up the good fight.

[tysontom]

>Hi Tom

>

>I am looking now for replacement woofers. I cannot seem to

>find NHT over here in England.

>

>What should I be looking for?

>Wattage - 400?

>Ohms - 8 or 4 ohms

>

>Freq got that 20hz ish

>

>Thanks

>Rob

Rob,

First of all, I agree with others here that the best and safest thing to do would be to put the original AR woofers, once repaired, back in the AR-10 cabinets.

Here are some questions for your re-worked AR-10Pis:

(1) Do you still have the original AR flat-side 12-inch woofers?

(2) Do the woofer cut-out holes still have the original T-Nuts?

(3) Did you enlarge the speaker hole other than the flat sides?

(4) Did you drill any holes for the new Eminence installation?

It occurs to me that if you only cut out a part of the speaker cabinet where the flat-side portion is, you should be able to put the original AR woofers back in place (once they are repaired), and there would be no air leaks. If you still have the original T-Nuts and gaskets and such, you should be able to get the woofers back in place. If you have enlarged the cutout or drilled other holes for the speaker screws, etc., then some cabinetry work will have to be done.

The next hurdle would be to take on the refoaming. You can easily get the refoaming kits from America, and have them air-mailed to you for probably $8-10.00 or so. Refoaming is really not difficult, and you don't have to change the dust cap or use shims or anything like that on the AR 12-inch woofer if the cone and voice-coil assembly are otherwise okay.

Good luck, and keep us posted. Get those AR woofers fixed and back in the cabinets where they belong.

--Tom Tyson

[roundhome]

Hello

try this for AR speakers and parts over there.

got were there is a U.S. military base check out the secound hand shops in the area and if you have them pawn shops around the base. Theer were a lot of ARs sold on the bases. I got my AR9s in Italy

Good luck And get some real woofers back in them.

Jim

[tysontom]

>From looking at the 10pi blueprint (ar10pisystemassymk1),

>doesn't it seem as if enlarging the hole to make a perfect

>circle would do structural damage to the cabinet, or is that

>just a cosmetic moulding at the sides?

>

>Adcom really appears to be a good choice for AR speakers,

>providing substantial power, and excellent low frequency

>control...wasn't C. Victor Campos involved with both

>companies?

I agree that Adcom is a good choice for AR speakers, primarily because they are compatible with low impedances and inductive-reactive loads. The bigger Adcoms seem to be very reliable, too, which is reassuring.

C Victor Campos was with AR in the early 1960s (he was in customer services), then left for KLH, but returned to AR in the mid-1970s. He was very involved with the development of the ADD products such as the AR-10Pi, and he orchestrated for AR the AR-10Pi live-vs.-recorded demonstration with drummer Neil Grover. He was also very involved with the development and refinement of the 1978 AR-9, one of AR's finest products. After AR he worked for NAD, whose amplifiers also seem well suited to low-sensitivity, low-Z AR speakers.

--Tom Tyson

[Guest SteveG]

Tom, Rob seems to have indicated that he might have cut more than just the flat parts out. he said the cabinet only retaing 4 of the 8 tnuts. I assume that there was some more extensive cut out therefore. Still repairable and very well worth doing for 10pi.

Rob---really hope you so still have the orig woofers. If not, they come up used on ebay all the time. Problem is shipping from the States would be steep. But this might still be a good option if local used stores don't come through!!

SteveG

[Guest Bret]

Rob,

Have you got a digital camera so we can see what you have left?

Bret

[tysontom]

>I have looked for the NHT1259 and AR woofers - no luck.

>AR doesn't exist over here and any audio store says no way and

>cannot help.

>Only one place over here offered to help and they came up with

>a 12" woofer by Peerless - 831857, which they say they use for

>all the AR speakers they come across.

>Specs as follows:

>

>831857 polymer cone Bass(Reference #peer16)

>89dB ~ 8 ohm ~ 315mm o/dia ~ 115mm deep ~ 39mm vc ~ 220w power

>~

>24Hz Fs ~ 20-1000Hz range

Rob, I forgot to mention earlier that the Peerless woofer you mention is also inappropriate for the 10Pi. It is 8 ohms, and the free-air resonance (fs) is too high at 24 Hz. It's not as rugged with its smallish voice coil. Mounted in the AR-10Pi cabinet it would sound thin in the bass, plus being 3-dB less sensitive than the rest of the drivers. The AR woofer is 4 ohms, and the fs is 14-18 Hz, for a mounted resonance (fc) of 41-43 Hz.

Once again the AR woofers would be best for the AR-10Pi, but we have not heard from you if you still have them. The NHT 1259 would also work well, but these superb woofers are at least $150 USD each, and apparently not readily available in the UK. The 1259 has about the same resonance as the AR woofer, but it has greater excursion and power-handling capability. The trade off is that the 1259 was not designed to work as well at the higher crossover frequencies.

--Tom Tyson

[Guest Rob]

Hi

Sorry for the delay. It took me a while to get camera going.

I have attached pics. Looking at the speakers ther are 8 screw holes left and I still have the screws to fit, so if I can get some replacement drivers I should be able to fill in the sides.

//

Rob

[tysontom]

>Hi

>Sorry for the delay. It took me a while to get camera going.

>

>I have attached pics. Looking at the speakers ther are 8 screw

>holes left and I still have the screws to fit, so if I can get

>some replacement drivers I should be able to fill in the

>sides.

Rob,

You did a fine job of routing out the hole for the Eminence woofer; you did no real damage to the cabinet as far as I can tell, and the T-nuts are still intact. Really all you need to do is find the AR woofers, or another set, and reinstall them with proper gaskets (or you can use Mortite) and you are back in business. You won't need to do anything to the cabinet unless you want a cosmetic improvement.

You should be able to locate the AR-10Pi drivers on eBay, probably there in the UK. You might have to get it from the US. The part numbers for the flat-side 12W woofers are listed below. These woofers are almost identical, and each has the same voice coil, magnet size, cone mass, etc., and all are compatible with your AR-10Pis.

AR#3700 (1954-1968) (This is the original Alnico cast-aluminum frame AR-1/AR-3 woofer, you could use this woofer in the AR-10Pi, but it is older and more fragile as far as glues separating, etc.)

AR#200003-0 (1969-1974)(AR-3a/LST first ceramic-ferrite woofer)

AR#1210003-2 (1975-1989 approx)(AR-3, AR-3a, AR-10Pi, AR-11, AR-LST, AR-1, AR-9, AR-9LS, AR-9LSi, AR-98LS, AR-98LSi, AR-78LS, AR-58S, AR-58B, AR-58BX and AR-58BXi).

Tonegen#12100032 (1990 or so till present) (Same as all the other) This is the Tonegen replacement woofer.

NHT#1259 (This woofer, which at $150USD/each is expensive, will now perfectly fit your cabinet since you have round holes. It was designed for the 3-cu.ft. NHT 3.3 speaker cabinet, but it has about the same resonance, impedance and so forth as the original AR woofer. There is some question as to how well it would do in the upper-bass frequencies, so it should not be your first choice unless you are an inveterate bass freak. The choke value might have to be changed as well. This woofer has significantly greater excursion capability; and with proper equilization, lots of amplifier power, you could turn your two AR-10Pis into powerful, full-range speakers with true subwoofer bass.

--Tom Tyson

[Guest Rob]

Hi Tom

I am getting my memory back now.

I did the job about 3 years ago. I cut the sides out with a small dremel tool and had to widen the whole aperture slightly to accept the Eminence woofers. I tried not to disturb the nuts in the cabinet.

Madisound have responded that they can supply a pair of NHT's Cost inc shipping is about $400 + duty.

I am going to keep looking for a pair of AR woofers and one of the previous messages about a US base is good as we have a US/RAF base about 5 miles away.

I will let you guys know how I get on.

Cheers and Thanks for your help.

Rob