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Do I Really Need a Sub?

MartinLogan Owners (MLO)

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Brad225

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Roebert, all 4 of mine were 1-2 years old when I purchased them from the original owners. I have had no problems other than I had to replace a fuse in one of them 4-5 years ago.
I would buy more ML subs should the need arise. Sorry to hear of the problems you have had, even from new.
 

Robert D

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Roebert, all 4 of mine were 1-2 years old when I purchased them from the original owners. I have had no problems other than I had to replace a fuse in one of them 4-5 years ago.
I would buy more ML subs should the need arise. Sorry to hear of the problems you have had, even from new.
Suppose I got a lemon.
 

ttocs

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I, like you, am using a high crossover setting for the Motif center. Yesterday I connected my small subwoofer, an old Rel R218, to my Motif center speaker. It's connected only through the high level input. This is where it got interesting, and a bit frustrating. Rel states many times how to adjust the settings when doing this, but it doesn't work for a speaker that is rated for only 73Hz, it's just not low enough. Rel says to set the XO on the sub to its minimum, 30Hz, then increase the gain until it matches the speaker, then increase the XO till it's too much and back off a little. Again, it just doesn't work. Lots of low freq comes through but nothing even close to 73Hz, so there's a gap. Lucky for me I have REW, which made it simple. It ends up that the crossover on the sub is now set to 120Hz, and the gain is set very low where it blends perfectly with the Motif at around 100Hz, which is where the frequency drops like a rock on the Motif. So this is working very well, very happy. Also, I was not aware at how much very low frequency audio comes through the center channel. I always thought it was almost exclusively for voice, it's not. Lots of low bass, music, sounds - but not LFE. So having a dedicated sub for the Center is a really good thing, the audio seems clearer and more natural. I'm hoping to even out a plateau the Motif has when it's calibrated.
Rel says not to worry.

ML says not to set the Motif as Large. At high volume damage can occur since there are very low frequencies in some movie content in the center channel. Since I don't know of a safe way to test this, gotta move on with other ideas. I watched parts of some bass heavy movies at low volume over the weekend and can definitely confirm there is very low freqs in the center channel, down into the 20Hz range. ML suggested using a sub with HPF, or use Processor to limit the low freqs with bass management.

Plan B. I've got a Behringer CX3400 XO I can use.
Processor Center channel out to Y cable.
Y cable out to sub
Y cable out to XO @44Hz out to amp to Motif.
 

BDH55

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Congrats!!
The important channels to keep isolated from all other duties for me are LCR. So you got my vote.

I used REW to tune a subwoofer for my center speaker. It was quick to do. Just made a sweep with center speaker only, then one with center and sub together and adjusted as needed for level, crossover, and phase. It only took maybe 8 sweeps to get a smooth blend.

I hope you got the sale price which just started this weekend for the T/9i.
edit: oops, I just realized that model isn't the brand I thought it was. Brain fart. sorry
Funny... I kind of busted my dealer for not telling me about the sale and after 'they looked into it' they couldn't find anything and asked where I heard this. Of course I just told them I would look into it but meanwhile they did tell me that they would 're-visit' the quotes they have out to me for both rear subs, as well as new main amps I am considering. I guess all's well that ends well...

I think I am going to have to learn tools like REW, whether I want to or not!
 

JonFo

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Plan B. I've got a Behringer CX3400 XO I can use.
Processor Center channel out to Y cable.
Y cable out to sub
Y cable out to XO @44Hz out to amp to Motif.
Scott, I recommend setting a center XO no lower than 70Hz, 80 or higher is best. For a Motif, I'd say 90 is probably ideal.
Again, assuming XO slopes are 24dB/Oct.

As a point of reference, my SL3XC center, with 6 x 7" drivers that is flat to below 50Hz (at 90dB, so very loud compared to usual metrics), I cross over at 80Hz to ensure it can hit 105dB SPL peaks with very-low distortion.
 

ttocs

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Scott, I recommend setting a center XO no lower than 70Hz, 80 or higher is best. For a Motif, I'd say 90 is probably ideal.
Again, assuming XO slopes are 24dB/Oct.

As a point of reference, my SL3XC center, with 6 x 7" drivers that is flat to below 50Hz (at 90dB, so very loud compared to usual metrics), I cross over at 80Hz to ensure it can hit 105dB SPL peaks with very-low distortion.
You know? I really should proof read better after a "copy/paste". That 44Hz is the minimum XO point on that device, not what I intend to use.

A few months back I found that setting the processor crossover for bass management at 150Hz and higher is a big improvement for the Motif. That's using just ears. FYI when I did this I had already routed LFE only to my subwoofers so all the bass management went to the 13A's set as Large in the processor. This was when I started questioning subwoofer usage in my system after such a big improvement from something so simple.

The last couple weeks I've been doing a lot of testing with subwoofers and in doing so I discovered something kind of disturbing about the Motif. Below the 450Hz crossover point to the woofers there's a 9dB jump in SPL between 100-200Hz. Really weird! At 100Hz it jumps up 9dB, stays at that level to 200Hz, then jumps down 9dB and stays at that level up to the XO of 450Hz. This is probably why I like the sound better with as high a crossover to the sub as possible. Basically, this is like saying "remove the Motif's woofers because they suck", except for the 200-450Hz range.
 

spkrdctr

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Have you had any issues with your depth i subs? Mine has had several problems and now once in awhile will emit a random period of a static scratching sound. I dont think I will buy another ML sub. Mine had issues right out of the box brand new.
Robert, if it had problems right out of the box, why did it not get returned under warranty? Just wondering......
 

Robert D

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Robert, if it had problems right out of the box, why did it not get returned under warranty? Just wondering......
I was ok with the shop I bought it from repairing it. The first problem was that it would never go into standby mode. It was on all the time, green light. They replaced the part that controls that and it was fine.

Not long later I noticed a whooshing sound with each beat. There was an air leak around the back panel I think. So they took it back and repaired that.

Years later the sub is making the scratchy static sound at random times. Something else is wrong with it now. I contacted ML and it was their opinion that it really isn't worth fixing. There is no telling whats causing the problem.

I plan on just using it until the scratching sound becomes more of a nuisance. Right now it only happens maybe one night every other month.

Thinking I may try Rythmik, REL, or JL Audio as a replacement and go dual.
 

spkrdctr

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I know my home theater system for movies, tv and music is not really appreciated here, but It was one of the reasons I said for guys buying a new sub to get a volume remote control. When jumping from FM radio to tv shows to streaming music to bluetooth it is impossible to leave the sub volume at one setting and forget about it. For me that is a must have and I don't have it on my sub so I have to constantly adjust the volume manually. Also, it can be controlled by my reciever but I have to work through a few menus. A remote would be awesome for me. So plan on how you listen if you need one. Im kind of a 5% here, the other 95% have systems that are much more alike!👍 Im an outlier!
 
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