XR-14 stand mounting

[leosagna]

Hi everyone. So you've all ruined me and I have picked up another piece of Mc gear. A pair of XR-14s with a few cosmetic happy accidents came up locally for a price that's less than some of you pay for your monthly cellular family plan.
My current setup was a C34V, the power amp section of a MA6100 (for now...), B&W 602 s2's and a ASW600 sub.
Holy Tony Soprano's oven fresh cannoli. I did not expect these speakers to impress me this much. The woofers were reformed and while they may benefit from a MQ10X, my sub and the C34's EQ and loudness do justice smoothing out the low end.
So now to the point of this post- While I do thoroughly enjoy random sounds coming from several feet away from the sides of these speakers; I'm used to a higher "plane" of the tweeters. In a way I feel like I'm sort of "looking down". Floor standers are new to me. Can I build stands to raise them 8-10" to bring the tweeters to ear height without ruining the bass, soundstage and imaging? From what I've read on his site, Roger was very meticulous designing this line of speakers and I don't want to make stands if it takes away from the placement of sound.
I appreciate everyone's responses and particularly would like to thank @c_dk for his many posts on the XR14 that made me pull the trigger. (and help with my volume pot issue, lol).

 

[damacman]

Why not try a short angled set of stands first? Although you may get a bit of a reduction in bass output by raising them off of the floor ...

 

[sKiZo]

You should be aware that any of the isoplanar series of speakers won't perform to factory spec without the outboard EQ. Like the Bose biguns, that's considered part of the crossover network. If you have that, you can fine tune the bottom end for various placements with the LF compensation controls. There's one for each side so you're not locked into a symmetrical setup.

As far as raising the speakers, I wouldn't see a problem as long as the risers have substantial mass to allow good coupling with the floor.

 

[c_dk]

Blind listening does not support the height allusion as much as you might think but there should be no issue with raising them up. Back in the day I lobbied Gow hard for a dual 10 inch woofer speaker with a cabinet volume 25 % bigger with greater height.

This was as much for the power handling with two woofers as well as the added perceived value of a taller speaker at a greater price. RR disappointed with the xr1051, a single 10 with a passive added.

As Skizo alluded to, the Mac speakers have a designed in controlled low frequency roll off, not the haphazard roll off of most all other speaker designs. RR designed in the roll off so that a EQ could be designed to counter it as well as adapting to the various positions the speakers can be placed in the room.

I do beleve in the past I have posted some real world response curves but still have not found my notebook with hundreds of room curves collected over the years. (wherever that notebook is it should have Skizo's original curve from back in the early 80s)

I have found that replacing the Zobel electrolytic caps with bypassed new and the goofy clip speaker connectors with five way binding posts a excellent upgrade.

 

[leosagna]

Thanks for all the suggestions! I'm currently keeping an eye out for a MQ102/4 and am going to play with room placement and tilt before I build some sturdy stands. I'm hoping to restore these so I'll definitely replace the crossover lytics and change the binding posts out while I'm in there. Seems like an odd choice to just use spring clips for such a large speaker.

 

[twiiii]

If you had a MQ 102 you wouldn't need to be asking the question. With the speakers on the floor against a wall you would be using setting 2 or possibly 3. Lifted 3 or but I doubt 4. You would probably want a 7100 /754 / or MC 122 for more power. You wouldn't need subs unless you prefer a heavier balance.

 

[sKiZo]

I'm hoping to restore these so I'll definitely replace the crossover lytics and change the binding posts out while I'm in there. Seems like an odd choice to just use spring clips for such a large speaker.

Change the binding posts? Sacrilege!!

(oh, wait ... great idea!) <G>

Changed mine over to banana posts some time back when I was in there resealing the boxes.

Also, if you're looking around for an MQ104 or similar that has the additional filter loops built in, DO make sure it comes with the factory capacitors. Those can be hard to replace if they're not included with the box.

I do beleve in the past I have posted some real world response curves but still have not found my notebook with hundreds of room curves collected over the years. (wherever that notebook is it should have Skizo's original curve from back in the early 80s).

Gives me an excuse to dig thru my pile of paperwork. Maybe I can come up with it. I've since retuned for the current room setup using REW and a calibrated mike with excellent results, but it'd still be good for historical purposes.

Also, I still use the LF compensation network in the MQ104. The cap filters in that are set up to handle my analog sources along with a parametric EQ, and the digital EQ compensates for that when I'm listening to the HTPC. Best of both worlds now.

 

[leosagna]

If you had a MQ 102 you wouldn't need to be asking the question. With the speakers on the floor against a wall you would be using setting 2 or possibly 3. Lifted 3 or but I doubt 4. You would probably want a 7100 /754 / or MC 122 for more power. You wouldn't need subs unless you prefer a heavier balance.

Another vote for me to pick up an MQ! Lol. Thanks for the advice! Looking into the current market, I may as well go for the mq104 with the added room cal over the 102. They seem to going for similar prices...

Power wise, I'm saving up for something from the mc2155 to mc7270 (7200 included). I've heard them meters take the soundstage to another level . For now, the 6100 and sub should suffice for the volumes that I listen to, and I have a 140wpc Carver amp I can swap in if I'm in an eardrum rupturing mood.

 

[leosagna]

Change the binding posts? Sacrilege!!

(oh, wait ... great idea!) <G>

Changed mine over to banana posts some time back when I was in there resealing the boxes.

Also, if you're looking around for an MQ104 or similar that has the additional filter loops built in, DO make sure it comes with the factory capacitors. Those can be hard to replace if they're not included with the box.

Gives me an excuse to dig thru my pile of paperwork. Maybe I can come up with it. I've since retuned for the current room setup using REW and a calibrated mike with excellent results, but it'd still be good for historical purposes.

Also, I still use the LF compensation network in the MQ104. The cap filters in that are set up to handle my analog sources along with a parametric EQ, and the digital EQ compensates for that when I'm listening to the HTPC. Best of both worlds now.

Wow those look great! Did you repourpose the original binding post plate or make a new one? Looks seemless!

Good call on the cap kit. Looking at the values from your photos some of those would be difficult to find on digikey/mouser.

 

[c_dk]

Properly setup with the MQ104 a pair of 14s can easily go deep into the 20-25 Hz. range with a setting of 3 for the bass EQ......which if I remember correctly is about 6 dB of boost at 20 Hz.

A sub should not be necessary.....and might really screw things up.

Also as you excite the room nodes it is not uncommon to see frequency aberrations at 60, 120 and 240 Hz. in the typical U.S. home.

I should really post some room response curves....

I also wish I would have been a bit more analytical as I measured hundreds of room/speaker systems back in the 70s and 80s......I did not include a tape measure along with my colored pencils in my kit so I never saved the actual measured room dimensions.

 

[sKiZo]

What, you didn't use depth sounding and lasers?

(Oh, wait ... they didn't have those back then) <G>

I do remember a really technical process involved in setting up and executing the tests and calibration. Then I think back to a few years back and my handy dandy little test kit put together out of spare parts. Results were quite nice - maybe not perfect, but a whole lot better than before, and I did run several sweeps and average them before locking it all in ...

 

[sKiZo]

Wow those look great! Did you repourpose the original binding post plate or make a new one? Looks seemless!

Good call on the cap kit. Looking at the values from your photos some of those would be difficult to find on digikey/mouser.

Original plate - only change is I added a gasket between that and the cabinet to seal any potential air leaks. The new posts are sealed at the back as well. The caps are more of a problem getting them to fit properly as they've modified to fit the sockets in the EQ box ... I also resealed the boxes completely at the corners as that's the likely spot to have separation over the years. Keep in mind these speakers are 40 years old!

In case you're wondering, there's two caps used in each filter loop. One sets the center frequency, and the other the bandwidth. Each can be fine tuned with the VRs ...

PS ... I did pick up a set of caps for the crossovers a while back but never got around to installing them. More important was refoaming the drivers, and I was happy leaving the board rebuild for one of those "gawd I'm bored" moments down the road that never happened.

 

[c_dk]

Is that display 1/3 octave pink noise?

It would be nice if the level were more detailed and seperated apart below 500 Hz.

Of the final five peaks the first three are uncharacteristic of the XR drivers.....the last two look like a mike issue.

 

[sKiZo]

Actually, the pic is just a software test, and it ain't even the software I used. It IS 1/3 octave in a program called TrueRTA, but didn't much care for that. I ended up using Room EQ Wizard here.

Don't quote me because my notes mostly suck, but I "believe" this is an actual test on the XR16's in my environment taken at the listening position using REW at 1/6 res. It MAY also be before I figured out you're best off pointing the mike UP for proper results. Colored lines are first pass actual, and the black lines are with the suggested filters applied (including a standard "house curve" overlay, and one of three sweeps to be averaged for the final results.

** Those MAY also be before I had the drivers refoamed. I did that myself, then had a coil go open on one of the big woofs. Took them into the Circuit Shop for that, and first thing counter guy said when I plopped them on the counter was "Nice job on the foams - too bad they're the wrong ones!" Mine didn't have the correct profile and were limiting travel, which might explain the bottom end dropoff in the graph. Or not. I forget. What were we talking about?

 

[c_dk]

A inquiring mind wants to know.......what is the room difference between the Kermit (green) curve vs the Barney(purple) curve? The peak at what believe is 90 Hz, valley at 200, and then the opposite a decade higher?

Is the K curve showing the speaker closer to a corner?

 

[c_dk]

This graph is of a pair of XR6s, same driver arrangement as the 16s before and after crossover restoration and MQ104 correction. We did have to negotiate moving the LH speaker inward a foot or so from the corner, with the interior decorator.

 

[sKiZo]

A inquiring mind wants to know.......what is the room difference between the Kermit (green) curve vs the Barney(purple) curve? The peak at what believe is 90 Hz, valley at 200, and then the opposite a decade higher?

Is the K curve showing the speaker closer to a corner?

Ida know ... I hardly remember yesterday, ok. <G>

K curve?

And I believe the colored lines are just left and right channel readings on the same test.

PS ... my speakers don't move much as I'm into the "holographic" thing here. Position and toe are impossibly meticulous ... to the point that I've marked the floor for proper positioning if I have to get in back. I use the LF boost controls on the MQ104 to adjust corner response.

 

[c_dk]

My color judgement is questionable so I assigned your top curve a greenish blue symbolized by Kermit (K) the frog.....

So again what is different with the speaker surroundings L vs R?