Keep my MTMs or ?????

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AvFan

Keep my MTMs or ?????
« on: 23 Dec 2012, 07:39 pm »
Below is a photo of a MTM kit that Rick designed for me in 2009 and I finished the cabinets in 2011.  They are wonderful speakers; the best I've owned.  They have a RAAL 70-20XR tweeter and SB Acoustics 5" mids.  Originally I planned to put them in a relatively small spare bedroom with an 8' ceiling.  The MTM would have been great in that situation as it naturally minimizes floor and ceiling reflections. 



But now the speakers are in my living room with high vaulted ceilings and open to the downstairs of my house.  The advantages of an MTM configuration may now be a detriment.

1.  I'm not always seated so highs are diminished when standing.  I've had more than one guest come in and politely compliment my system but when they sit down most are speechless or just say "Wow!".
2.  I've noticed the center image (e.g. vocals) is lower than the 38" tweeter height by nearly a foot.  Sort of a "V" shape to the sound.  I recently flipped the tweeters to no effect.  This is a mystery to me and I wonder if this a function of the crossover or the MTM design itself.   :dunno:
3.  I'm currently using two small subs in stereo but I have some bass peaks in my room.  This is not an issue with the MTM as the subs don't have any EQ capability.

So I'm looking for suggestions on different speaker types better suited to my fairly large living room.  The only real limitation is I want to keep the RAAL in the mix; that thing is amazing.  I will build new cabinets and they can be floorstanders or monitors on stands.  Full range or monitors with sub below in a single cabinet would be nice too.

So what do folks suggest?

JoshK

Re: Keep my MTMs or ?????
« Reply #1 on: 23 Dec 2012, 08:12 pm »
Cheap thing to try is angle them back a bit, so put something under the front feet.  This will point the center lobe higher.   This might mildly address #1 and #2.   #3 is just a bass room integration issue, which will exist regardless of what you choose for mains.


Carl V

  • Full Member
  • Posts: 571
Re: Keep my MTMs or ?????
« Reply #2 on: 23 Dec 2012, 08:25 pm »
1st, nice work on your DIY speakers.
2nd, Josh's suggestions are good.

There is a difference in Sound stage etc. when listening to MTM VS other designs.
Preferences will come into play.  I've listened & owned a few of Ricks designs both
MTM or MT.  The Adage Horses for Courses ...comes to mind.

You might ask Rick if he could re-purpose your drivers & Enclosure for a 2.5 design
similar to his TRT.  Whereby you have an MT-.5M. Maybe these mid woofers can do double
duty or perhaps another mid-woofer could be substituted.

If you're itching to make sawdust..... a three way floor stander of Ricks design might be
what the Rx you need. Reuse the tweeter & mid-woofer perhaps and simply add a 10" woofer.

Personally not a fan of Powered subs in the base of Speakers as a general rule. Largely because
where the Speaker ought to be for mid-range, etc., is  often not the best location for Sub-woofer
freq. generation. imho. ymmv

Call Rick.

JerryLove

Re: Keep my MTMs or ?????
« Reply #3 on: 23 Dec 2012, 08:28 pm »
2.  I've noticed the center image (e.g. vocals) is lower than the 38" tweeter height by nearly a foot.  Sort of a "V" shape to the sound.  I recently flipped the tweeters to no effect.  This is a mystery to me and I wonder if this a function of the crossover or the MTM design itself.   :dunno:

I don't *know*; but from what I've read I would suspect the crossovers.

AvFan

Re: Keep my MTMs or ?????
« Reply #4 on: 23 Dec 2012, 10:02 pm »
Cheap thing to try is angle them back a bit, so put something under the front feet.  This will point the center lobe higher.   This might mildly address #1 and #2.   #3 is just a bass room integration issue, which will exist regardless of what you choose for mains.

Thanks for the suggestion!  I maxed out the front spikes and it raised the center image and it is now just a couple of inches below the tweeter level.  It sounds much better and it probably would not be noticeable to the casual listener but the speakers look kinda funky angled back that far.  They are tipped back at about 2.5 degrees or 2" back at the top of the speaker.  But, hey, it worked.

If you're itching to make sawdust..... a three way floor stander of Ricks design might be
what the Rx you need. Reuse the tweeter & mid-woofer perhaps and simply add a 10" woofer.

Sawdust and Rick's speakers are good medicine... :D


aevans

  • Jr. Member
  • Posts: 62
Re: Keep my MTMs or ?????
« Reply #5 on: 23 Dec 2012, 10:09 pm »
The dispersion pattern on the raals is a bit harsh on the vertical transition. It's extremely focused. The foam cores help smooth it out, but it also kills the sensitivity and the crossover would need to be adjusted to get the same sound levels.. I noticed that it also smashes some of the details - which defeats one of the reasons for running a raal in the first place. I think the further you can get away from them as far a seating position the better off you are to have the transition from standing to sitting work better.. of course the best fix is some 7 foot tall line arrays.

JoshK

Re: Keep my MTMs or ?????
« Reply #6 on: 23 Dec 2012, 11:07 pm »
Yeah it might look a bit funny, but its worth trying out to see if it fixes the issue since it is free and worthwhile experiment.

I'd find something like a couple books and keep tilting it back further and test the limit of the experiment a bit.   It will give you perspective on whether the center lobe is and where you want it to be at optimal listening distance.   You can always remove the lift for decor reasons and put it back for listening. 

The standing versus seated issue is more likely the tweeter's narrow vertical dispersion and likely to persists even with a different speaker.  Its just what a RAAL tweeter does, for better for worse.   The woofer/tweeter crossover does things to the center lobe which is addressed with the tilt, but then again so is the RAAL's limit addressed by the tilt. 

AvFan

Re: Keep my MTMs or ?????
« Reply #7 on: 24 Dec 2012, 12:33 am »
I certainly appreciate everyone's thoughts on what I'm hearing from my speakers.  I didn't mention it but aiming them up helped with the highs when I was standing about 12' to 14' away.  I'll fine tune how far to tip the speakers to get the center image in the right spot when seated.  I suppose I should have noticed all this before now, but I just got my full system assembled (several vintage components and the topic for another thread!) in the last couple of months and I've spent more time listening to music.  My seating distance is also further back now that the system is in my living room.  Finally, I haven't had many speakers (and nothing of Selah's caliber) to compare these MTMs to.  Thanks again!

JoshK

Re: Keep my MTMs or ?????
« Reply #8 on: 24 Dec 2012, 12:57 am »
Happy to help, if I did.   We can all get nervosis over stupid stuff, so its always good to step back and test simple/cheap things first.  That at least puts context/rationality to the issue.