Martin Logan 1000W Subwoofer

[Ron Texas]

This subwoofer was recently discontinued and is now on sale for $700 (plus sales tax) instead of it's $1000 list price. At full price I probably would not have looked at it.

The 1000W has a 12' down firing driver in a 14" cube shaped sealed box with a 500 watt RMS amplifier. It has wireless connectivity via a stable bluetooth connection which I am using right now. The driver appears to have a plastic cone and a large synthetic rubber surround. Connectivity is limited to line level either dual RCA, LFE or wireless. Phase has settings for 0, 90 and 180 degrees. A crossover knob is marked 35hz at 7 o'clock and 120 at 5 o'clock with no other markings. I found an online tone generator which enabled me to do an approximate calibration. I have found the volume control is extremely sensitive at the low end. Because I am using it with low sensitivity LS50's the volume setting is pretty low. Advertised frequency response is -3db @ 22 hz anechoic. In room it's around 25hz or a little higher. Without room reflections the response is likely flatter and it mighture better.

The main chore in setup is avoiding room peaks. I used the reverse crawl method, LOL. That is, I have carried the 37 lb unit around the room and checked it's response at various locations. My solution may be counterintuitive because the sub sounds best very near one of the LS50's where apparent bass is not maximized. However, the speaker locations were chosen to minimize room peaks. Getting the sub away from room peaks minimizes the one note effect and allows a higher gain setting. Wireless connectivity made moving the sub around the room a lot easier because all I have to do is move it, sometimes unplugging it. Messing with cables is a lot more work. Also, I am using the DSP built into my Crown 1502 to roll off the LS50's.

My usual SQ comments, hints of diesel electric locomotives moving slowly and excavators pulling down old houses mixed with the comfy warm feeling of a kitchen fire while drinking bourbon laced with arsenic.

 

[Fitzcaraldo215]

The sub is probably a good deal. Don't know if you have a suitable mic, but REW measurements might help better fine tune the sound.

I don't independently measure. I just use Dirac Live together with bass management in JRiver for a single JLAudio sub in my Mch system. Integration, extension, articulation, lack of boominess have never been an issue and without doing a lot of tweaking. I am quite happy with the sound and really see absolutely no need for improvement. The sound is quite cohesive with improved dynamics, yet the sub never calls attention to itself. It makes music sound much better. I like what it does very much.

 

[Olli]

Here‘s some nice advice on setting up subs that worked well for me in case you are interested:

http://www.soundoctor.com/testcd/index.htm

There is less heavy lifting in his approach

 

[Ron Texas]

Today I tried the subwoofer crawl laying the sub on my couch sideways and going around the room to find the loudest place. The result was very different at 30 hz than it was at 40 or higher frequencies. There was a spot where 30 hz was strong and 60 was reduced. I am going to use that spot for now. ML says this sub is convertible to front firing if mounted in a cabinet. However, the controls wind up on the bottom with the knobs in back in a nearly unreachable spot.

It looks like the optimum crossover frequency is 50 hz. That happens to be the frequency the port is tuned to and what SVS recommends for their 12" sealed box sub. For a ported stand mount this is probably the best place to start. Also, I used the KEF supplied port plugs. It helped and is something to try with any ported speaker.

My objective is an improvement in music. For movies it makes a difference, but the volume can be set higher.

 

[andreasmaaan]

@Ron Texas which port is tuned to 50Hz? The loudspeakers’ ports?

If that’s the case, this will be a very difficult frequency to cross over to the sub at due to non-minimum phase behaviour at the port tuning frequency, which will prevent the crossover from summing correctly. Better to go around an octave higher of possible.

EDIT: I misread your post - you're plugging the ports. Disregard my question

 

[oivavoi]

Seems like a good subwoofer! I would also say that the ideal crossover frequency is much higher, though. So the Crown 1502 has a built-in crossover? Neat. If it’s adjustable, I would have tried something as high as 100 hz, perhaps even 120 hz, if you have it placed close to the mains.

Reasons: a two-way like the LS50 will benefit from being relieved of the deep bass. 50 hz doesn’t make a big difference, there ain’t too much down there in any case. Most of the heavy hitting in the bass happens between 120 and 60 hz. Your LS50s will thank you if you let them off those frequencies. In addition, to get a smooth integration, you want the main speakers and the sub to have a more or less equal capability at the crossover frequency. If either the mains or the sub have low capability at the crossover frequency, it wont be as smooth. The 5-inch driver in the LS50 has no business at all messing around down at 50 hz. Even 100 hz is pushing it. Around 120 hz though, it’s still capable. So if you can make it work crossing it over that high, my advice would be to try it out.

 

[Ron Texas]

I tried 80 hz, but thought 50 worked better because the room has a peak at 60 and I could tame it by setting the crossover in the Crown 1502 to 71 hz. When running a sweep through the frequencies there is a slight dip in the mid 60's.

The Crown amp is adjustable and has all sorts of DSP functions.

I could give it another try at a higher frequency later today. What I can say is with the current setup large excursions of the LF driver have disappeared and the midrange is cleaner.

 

[oivavoi]

Cool, sounds like it’s already functioning rather well, then!

 

[Ron Texas]

Cool, sounds like it’s already functioning rather well, then!

It appears the peak at 60 hz has been tamed, but there is one at 95 hz which keeps me from raising the crossover frequency on the sub. The dial is not calibrated and I think the position I was using is actually 60 hz.

That said, I raised the high pass at 100 hz and will play with that for a while. The tone sweep is reasonably flat from 100 hz on down and I can now hear output at 20 hz.

 

[Ron Texas]

I pretty much have this beast tamed. Sub now set to roll off at 70 hz.

Interesting article by Robert Harley: http://www.theabsolutesound.com/articles/subwoofer-basics/?page=2

 

[HispanicPanic]

I've got the Martin Logan 700 and i find it exceeds my needs for bass. I've got the sub sitting on an ISO Acoustics isolator as i found my house's resonant frequency really ruined certain frequencies of bass for music. I do mostly music and listen to it all over the house (open floor plan) and if i stood too close to a wall my ears would be drowned out with a specific bass frequency. The isolator cleaned everything up REALLY well. I've got the sub facing my couch at a 0 deg phase. The bass is CLEAN and responsive. Paired up with Emotiva active 6s's, the filter is set also at 70 hz and i've got gorgeous clean sound for dayyysssss. I don't do bluetooth because i don't believe in it yet. Volume is set at 40-45% mark, i find that's a perfect level for my music i listen to, and when i watch movies the whole house shakes. The house 2 houses down complains they can hear my bass when i've got music going.

My neighbors hate me, and i don't care.

 

[Willem]

That is a bit antisocial I would think.

 

[HispanicPanic]

That is a bit antisocial I would think.

Well..... my neighbors are...... special. Not the good kind of neighbors, but that's beyond the scope of this forum and post.