XR6 Isoplanar Loudspeakers on the way

Gregory

Soundco Kid

Introduction

After 7 weeks the seller and I have finally agreed on a price for his XR6 speakers which are in FINE shape (except for the drivers.) He's the original owner and has the MQ104 and all the manuals still in plastic sleeves. Can hardly wait to pick them up. It will be a month or two before they're ready for regular service. This could be the answer to the strident Thiels...which are very accurate but bright and analytical.

It's so exciting that I've already changed the Sig file below!!

In the recent C33 discussion, the Owners Manual PDF doc shows a MR80 connected to the preamp, which is connected through a MQ104 to 2255/2205/2200 type amps with pairs of XR3/XR5/XR6/XR7/XR14 series speakers. This is like re-living my college years!! They fall right in that late 70s and early 80s period.


-Greg
 
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congrats with the new speakers.

I have the XR5 they are nice, so i can only imagine the XR6 is nice :)
how much did you pay for the XR6 ?
 
congrats with the new speakers. I have the XR5 they are nice, so i can only imagine the XR6 is nice :) how much did you pay for the XR6 ?

I'd rather not post the amount, but was able to negotiate the price some 20% lower, and he also threw in the MQ104 Equalizer. Was sure the capacitor kit came with the EQ but yesterday he says that he didn't have it. I'm mostly interested in the BASS contour section. Will probably run them straight through after playing around with the MQ104. We'll see.

The XR6s are still in the trunk of the car out in the garage. The neighbor isn't home to help unload. You can imagine I'm chomping at the bit to get them up in the listening room!!


-Gregory
 
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Of course, you knew this was coming.....................

:worthless

Inquiring minds want to see the grill hinges in action.

This is like re-living my college years!!
kewl.gif

-Gregory
Did not realize the MCD7007 was that old.:D
 
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Of course, you knew this was coming.....................

:worthless

Speakers STILL in trunk – need help unloading!

The neighbor hasn't come home for the weekend yet. Want to come over and help unload them? :D

XR6_trunk_1.jpg


XR6_trunk_2.jpg

The lady of the house says..."you have no patience!!" Can you believe that? :no:


-Greg
 
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Well.........I do like to visit DC, but 150 miles is a bit of a drive to help you unload speakers. We'll likely be down next month if you can wait. Then we can have dinner at Bistrot Du Coin.

On the other hand, I unloaded my 80-odd pound speakers and moved them into my basement living space by myself. Just go slow and easy and figure out how to do it moving one end at a time. For instance, rather than picking them up to move, lay one of them on that cardboard and slide along. Same with going up or down stairs. Use cardboard as a 'slider'. Has worked well for me for moving not only heavy speakers, but getting items as large as an MC602 (ugh - what a beast) down and then up the stairs. One step at a time.
 
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well I just got some xr7's whick cost $370 after refoaming. They are great, I love them, using a 2105 till my 2205 comes back. Greg I think you will find the bad rap Mcspeakers get is TOTALLY unwarranted. I am running an MQ101 with mine. Seems the XR was meant to be used with 2205 amp judging by production dates.
 
Well...I do like to visit DC, but 150 miles is a bit of a drive to help you unload speakers. We'll likely be down next month if you can wait. Then we can have dinner at Bistrot Du Coin.

The XR6s are finally up in the listening room!!

Some pics are posted below. They are beautiful and practically NEW looking even after 29-3/4 years (Aug 1980).

XR6_008.jpg


Now compare to the size of the Thiel 3.5 which is 6-1/2" taller but the XR6s are 35% wider.

XR6_014.jpg


If you look carefully at the woofer surround, you'll see that it's a bit yellow and crisp, so the 12" drivers must be refoamed. The Upper Mid domes need to be rebuilt as well. The seller already refoamed the 8" drivers.

XR6_019.jpg


Slight damage in transit

Unfortunately we had some difficulty loading. The XR6s just barely fit into the trunk sideways. One of the quilts didn't get wrapped around the aft speaker (closest to the trunk latch) as it was being used to cover the trunk ledge. So about 1" of the rear-to-side edge (near the top) took some compression damage where it was riding on the uneven trunk floor.

The back-side veneer is protruding past the edge. It's very minor and maybe someone in the DIY forum can advise on using a wood clamp to `press´the area back in slightly. No cuts or anything...just crushed a bit and the edge is no longer straight.


-Greg
 
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Very nice. You must drive a Buick to fit those in the trunk end-to-end.

Who does rebuilding of those dome mids? That is what has always held me back on owning a pair of the XR'x' line of speakers. Where to get service on the dome mids.
 
well I just got some xr7's which cost $370 after refoaming. They are great, I love them, using a 2105 till my 2205 comes back. Greg I think you will find the bad rap Mcspeakers get is TOTALLY unwarranted. I am running an MQ101 with mine. Seems the XR was meant to be used with 2205 amp judging by production dates.

Mcspeakers? Please! we're not talking fast food here. :no: Lol

The sound must at least be comparable to my 3-way, 12" H.H. Scott S-71s which I played for many many years, including before and well into the McIntosh amplifier days. The design of the XR6s is incredible, but we'll have to see about the quality.

The main reason for seeking out these speakers was to get a warmer and more robust sound...not as strident and tight as the Thiels. My aging and damaged ear cannot take much more of that.


-Greg
 
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Very nice. You must drive a Buick to fit those in the trunk end-to-end. Who does rebuilding of those dome mids? That is what has always held me back on owning a pair of the XR'x' line of speakers. Where to get service on the dome mids.

These XRs have BIG and beautiful cabinets, they're more like furniture! Should post a side view later. The upper-mid domes are bing sent back to McIntosh under an RMA to have them rebuilt. I'd say one would have high confidence the job would be done correctly.

How did you know it was a Buick? :idea:


-Greg
 
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These XRs are BIG and beautiful cabinets...they're more like furniture! Should post a side view later. The upper-mid domes are sent back to McIntosh under an RMA and they have them rebuilt. I'd say one would have high confidence the job would be done correctly. How did you know it was a Buick? :scratch2: -Gregory
You are talking to someone with a few 100K miles in a couple of Roadmasters. Wonderful, luxurious land yachts. 28mpg on the highway with the last one. And lots of hauling room in the trunk. But, am downsizing everything so now drive a Malibu that averages 28mpg and has more room in the back when the seats are laid flat.

What is the cost from McIntosh to have the domed mids rebuilt?
 

Cabinet side view


Here's a side view of the cabinets that show what extraordinary condition they're in. The seller had a beautiful air-conditioned home with the XR6s up at chest level on custom wall-to-wall, built in shelving where the speaker cabinets were totally protected. There are only the most minor blemishes in the finish and grills, and they're surprisingly free of dust and film.

XR6_side_back.jpg

Just beyond the second cabinet you'll see a blue-yellow cover. That's the 2205 on a test stand in front of the rack which had POWER OUTPUT tests run recently. In the far room (the kitchen) you can barely see a 2505 amplifier on the bench (kitchen island). It's about to get a `cap job.´


MQ104 Re-cap

The MQ 104 has several electrolytic caps in the signal path and power supply. I'll be using this device for BASS contours. It's a high-quality unit with a definite McIntosh look and feel. More on the MQ 104 later.

MQ104_006.jpg


There are now 21 separate McIntosh servicing/upgrade/rebuild projects on the TO DO list. Last night was XR6 inspection and note-taking/sketching with call-outs. Also completed was `inventory electrolytic caps on hand.´

Everything gets new stainless steel screws in either bright or black oxide!


-Greg
 
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Mcspeakers? Please! we're not talking fast food here. :nono: lol

The sound must at least be comparable to my 3-way, 12" H.H. Scott S-71s which I played for many many years, including before and well into the McIntosh amplifier days. The quality of the XR6s is incredible. The main reason for seeking out these speakers was to get a warmer and more robust sound...not as strident and tight as the Thiels. My aging and damaged ear cannot take much more of that.


-Gregory

alright greg, no fast food reference in this post! :D. The bass is well defined as I hear it, some many say they "lack bass" but I find there is plenty of bass you can really hear the notes that are being played, its not the 'heaviest" bass, but its more musical. these speakers are more balanced across the spectrum I think. Some may say the EQ isnt needed, and to that I say, it depends on what you like, but the EQ helps alot. Throw in the fact that you and I have c33's with the EQ on that as well, which most people who originally boought the XR/MQ101 combos were not running at the time, you have a VERY ajustable range, almost too much! you can do alot. spend a few weeks, you might not look for speakers for a while......unless you find a good deal on XR7's! try and get another pair of XR'6 at least and hook'em together, the cabinets can fit together like legos and you have the poor mans XR290! :)
 
The bass is well defined as I hear it, some many say they "lack bass" but I find there is plenty of bass you can really hear the notes that are being played, its not the 'heaviest" bass, but its more musical. these speakers are more balanced across the spectrum I think. Some may say the EQ isn't needed, and to that I say, it depends on what you like, but the EQ helps alot.

Throw in the fact that you and I have c33's with the EQ on that as well, which most people who originally bought the XR/MQ101 combos were not running at the time, you have a VERY adjustable range, almost too much! you can do alot. spend a few weeks, you might not look for speakers for a while......unless you find a good deal on XR7's! try and get another pair of XR'6 at least and hook'em together, the cabinets can fit together like legos and you have the poor mans XR290! :)

The Owner's Manual clearly states the woofers begin to roll off at 140 Hz by design, and are down 18 dB at 20 Hz. With the MQ101/102/104 Low Freq COMP section switched to position 5, the overall response is extended flat to 20 Hz.

According to the manual, the response also depends on where in the room the speakers are placed, i.e. corner or in mid-room. There's a trade-off in cone motion and distortion, so if you're cranking at HIGH power levels, there's the option to reduce the LF boost.

I'd not recommend hooking together two pair of speakers as you suggest. Already there are amplitude dips with 600 Hz CW tone when moving around in AZ and EL.

I hope the image is going to be stable.


-Greg
 
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keep us informed when you listen to them.
Ok, will do.

Inspection

Tuesday night was inspection...making sketches and note of items that need attention. There are only three of the most minor flaws in both cabinets combined, and you must be up really close to even detect them. Here is a photo of the XR6 (built in 1977 or 1979) standing next to the Thiel CS3.5 (built in 1988).

XR6_005.jpg


The Thiel is a tall 10" system and the XR6 a 12" system. Knocking on the Thiel cabinet with knuckles... it seemed more dense but it's tapered and slender. The McIntosh cabinets have the look and feel of high quality.. like fine furniture!!


Functional checks

Wednesday (last night) was functional checks with Audio Generator. CW tones were fed to each speaker in mono mode at the midband point of each driver, the crossover frequencies and several bass frequencies. There were no surprises as everything worked including the BASS Comp section of the MQ 104. Here is a photo of one XR6 with power being fed to it.

XR6_006.jpg


Bad drivers

As already discovered at the sellers home, one of the upper mids (UM) was dead. It measured as an open circuit with a DVM on the bench when disconnected. Below is a photo of the cabinet with the UM dome removed. The cabinets are truly in great shape!

When exercising the woofers at 20 Hz using MQ104 BASS boost settings, and due to the deteriorated surrounds, the RIGHT woofer started to make an awful whop-whop sound like a UH-1 chopper in Vietnam. It had that familiar cyclic `whop-whop-whop´ and I figured it should be shut down immediately before any damage occurred.

XR6_033.jpg


Here is the UM dome on the scale. It weights in at 1.6 lbs. Figure a total of 4 lbs for shipping. :yes:

XR6_029.jpg


Dissimilar screws

A strange discovery.. the UM screws holding the GOOD upper-mid were undersized (6-32) with flat washers. They weren't tight at all, as the holes are for 8-32 screws, so there WAS a surprise!! No matter because ALL driver screws will be replaced with NEW black oxide coated stainless steel ones. Some of the Phillips heads are `lunched up´ and others are starting to rust slightly.

XR6_038.jpg


McIntosh Matrix

One last point of interest. Today at lunch hour I threw together a time line of the components here, with a few extras for comparison. See table below:

Mc_matrix.png


This might be a good point to start a XR6 Love webpage. Maybe post here or host it on Comcast. It will be a fun project. These are NICE speakers and the hope is they will sound as good as they look!!


-Greg
 
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Bill Legal at millersound in PA will do them for 25-30 each and his turn around time is one week.
 
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