Just won this guy in an auction for $270. It will be the first sub I've used since I had a Sony SA-WM250 a while ago (which I soon realized was CRAP and was quick to get rid of it when I upgraded mains).

I was looking for the most solid and musical sub for my small 10.5'x12'x8' room (under $500) and found and bid on the M&K rather spontaneously. I was also interested in the Hsu VTF-1, Martin Logan Dynamo, and some Velodyne's. Then I heard some M&K subs at a showroom. Well, not at first because they integrated so well I didn't even think about the fact there was a sub playing until someone told me.

The MX-70 is apparently their smallest push-pull with two 8" woofers and seems like it will work well in my room. Anyone heard it? Are there any better options around its (used) price?

Thanks

The difference compared to the Sony should be night and day. M&K subs are legendary and used in pro recording studios. I’ve not heard the MX-70, but I’ve heard other M&K subs and they have made me drool, I wish the company was still in business. Sony subs are imo the worst subs on the market, I’m willing to bet that the MX-70 will destroy the Sony in terms of performance, You should be very pleased.

As per other sub options, I have an eD A3-250 ($350) that performs flawlessly, Great for music and killer for movies.

Jeff-


Jeff-

The difference compared to the Sony should be night and day. M&K subs are legendary and used in pro recording studios. I’ve not heard the MX-70, but I’ve heard other M&K subs and they have made me drool, I wish the company was still in business. Jeff-
Ascend should be out with a sub in the near future and the owner having been a long time M&K engineer, I'd expect nothing less than at least comparable SQ at a ID price.

David

I owned the MX-70b. Very musical but lacking in the extension department. If this is used for pure music you will be pleased.

Oh it CAME! This thing is quite hefty for it's small stature. It feels like a solid hunk of wood. I've just got it set-up right now in between my mains, in front of my equipment rack. I set the crossover to around 45Hz (my C-9s are rated to just above 30Hz), turned the volume to half way, and played the second track off of the new Chemical Brothers album "We Are The Night". This song starts off with a distorted frequency sweep that goes REALLY low. In fact, I never realized how low until just now. I've got the grill off the MX-70 so I can see when the woofer starts doing it's thing, and it gets to the point where all I can hear is a low rumbling, and I can feel the pressure in the room. The woofer is going mad at this point, so I'm thinking I'm getting good output at least into the low 20s.

The best thing is it doesn't even sound like a sub is playing. This thing is solid solid SOLID.

I'm going to listen to some nice acoustic stuff to see how well it integrates under strict conditions. My guess is, quite well.

I'm so very pleased. $300 well spent.

Congrats. The M&K dual push pull subs are very articulate.

Oh my god. I'm playing Shadow of the Colossus on my PS2. No words...

Well, I can't seem to find any fault with this guy. It's fantastic. I moved it into the back corner of my room, behind the right speaker. The output increased DRAMATICALLY, and I had to turn the volume from half way, to about a quarter to not mess up the balance (too much ;) ). I seem to have lost just a smidgen of solidity due to room loading, but it's still really good and integrates seamlessly. Localization is not a factor at all with the cutoff set under 50Hz.

There's only one thing that I want to deal with. When it's plugged in, regardless of whether it's getting a signal or not, and regardless of the volume I set on it, there's a low humming I can hear. It was next to inaudible when it was near the center of my room, but having it in the corner has amplified the sound a lot and I find it annoying. Thing is, the humming will suddenly get quieter, and then louder again a bit later. These are immediate changes. It will also switch pitch, up a bit, then down a bit, randomly. It's AC plug only has two prongs (ungrounded). Could there be a grounding issue?

I plugged it into my pre-amp, into one of the switched outlets, so at least when I turn that off, the sub will stop humming.

Any advice on how to fix this?

edit: Ok, tested something very simple. I turned the pre-amp on (so sub would turn on), and there was humming. I then unplugged the sub cable from the back of the MX-70. Humming stopped...

Could the reason be that I'm using some cheap Monster Cable stereo IC (I just have the left channel cable going from the mono pre-out of my pre-amp to the left channel (mono) in on the sub)? Do I need to get a special "subwoofer" cable? What's the difference between those and normal stereo ICs?

Ok, just bought a Monster MSB1000SW subwoofer cable. Yeah, Monster... it was cheap though. No way I'd spend the retail for that thing. Hopefully that will help, if not fix things.

The new cable hasn't come yet, but I've done some more experimenting and have lessened the problem in the mean time. The sub was plugged into the wall, so I tried plugging it into my Monster power center thingy and the humming was lessened a little bit. I then just messed with the positioning of the IC until the the sound was less and less audible. If I unplugged the IC from my preamp and lifted it up, I could hear some radio station quite clearly through the sub. It makes the least noise when low to the ground, but up away from power cables. The humming is now just audible from the listening position (improved from very audible and annoying). I'm hoping the better shielding on the new cable will take care of things.

I've got an old M&K MX-90 that I use in a dedicated audio setup. I have had it for 16 years now, and I plan on having it for a lot longer. I love the sound and build quality. I've dragged the thing to about 4 states in various moves.

I haven't had any issues with humming. I have always thought that humming in audio gear was related to some sort of grounding issue. Take that with a grain of salt, as I certainly am not an electrician/electrical engineer type.

Well, keep in mind I'm just using a cheap stereo IC right now. It probably has for **** shielding. I noticed that my pre-amp also has just a two prong plug. Is this an issue? I think it's just the cable because I get humming as well as radio even if it's not plugged into the pre-amp (which increases greatly if I'm holding the cable).

First, many if not most receivers have 2-prong plugs.

You will notice the MK sub has only a 2-prong sub -- this means you CANNOT get a "ground loop" with it.

But you CAN certainly reproduce hum if there is already hum coming down the cable; also you will get hum if the cable is broken, damaged, or has dubious shielding.

In tricky situations, you must determine what you REALLY mean by "hum". Is it 60 Hz hum? Is it 120 Hz hum? Is it an odd buzzing which cyclically repeats every 14 seconds? That's 59.94 video beating against the 60 Hz powerline, caused by a groun voltage differential between your CABLE COMPANY "ground" and your "building" ground.

You might try disconnecting the cble TV type-F connector and hear what happens.

The real reason I commented is to ask what color the amp plate is. Is it red? you might have one of the last production "kind of special" 70's, and you might also look to see just what the dust cover on the drivers say - they might say nothing, Discover Deep Bass, or SuperFast Deep Bass. Also some of the newest drivers escaped the factory without the screened dustcaps so anything is possible. All that really matters is that you enjoy it !

Barry

The real reason I commented is to ask what color the amp plate is. Is it red? you might have one of the last production "kind of special" 70's, and you might also look to see just what the dust cover on the drivers say - they might say nothing, Discover Deep Bass, or SuperFast Deep Bass. Also some of the newest drivers escaped the factory without the screened dustcaps so anything is possible. All that really matters is that you enjoy it

The amp plate is black. The dust cap says "Discover Deep Bass". Is this good or bad...

I can say that I am definitely enjoying it though! I'm finding it difficult to integrate with my C-9s though. Not that that really matters as I got the sub because I'm going to replace the C-9s with bookshelves. I think the C-9s have too much bass presence already, so with the sub 30Hz is quite loud, 40Hz and 50Hz are REALLY loud, and then depending on whether I've got the crossover at 40Hz, 60Hz sounds recessed, or if I up the crossover to 60Hz, 80Hz sounds recessed. I think integration with bookshelves that only go down to 50Hz or so will be easier.

Well, that nice cable came today and I hooked it up. Aaaaaaand... no difference. :mad:

It actually seemed to make the humming worse at first. See, while I've had my sub hooked up for a few days, it's sounded like the humming had lessened and lessened. Right before I unplugged the cheap cable, I could almost not hear anything at all. Nothing has changed back there in those few days. Weird.

Anyway, as soon as I unplugged it I was surprised because I was hearing a LOT of noise all of a sudden. What the hell? Another strange anomaly I discovered is that if I place my hand fully on the top of the sub (just the wood), the humming reduces BUT I hear radio much clearer. If I place both hands on it, there's basically no humming at all and I can hear radio even better. :confused:

When I plugged the new cable in, the humming died down but was still quite audible. I actually messed with the sub's power cord a bunch, moving it around and noting the differences. When holding the cord, humming increased. If the cord was lifted above the sub, humming increased a lot. I finally laid it down in such a way that the humming was almost not audible. I then messed with the positioning of the new IC until the humming was lessened even further. I noticed the new cord was better in that humming didn't get worse when I was holding it vs. it just laying on the ground. So better shielding, yes.

Another thing that helped actually was putting the sub's grill back on. Now I only really hear hum if I put my face directly in front of the sub.

Of course, I'm thinking "Why do I have to do this?! I should be able to just plug this sub in and connect an IC and not have any hum."

So, this isn't normal right? Should a sub be able to get audible hum and radio JUST being plugged into the wall? If there's something wrong with mine, any idea what it might be?

See if you can determine (with the aid of a portable radio) what station you are getting. Is it AM, FM or a TV station?

What city are you in?

The black plate/discover deep bass is the original model. While the bass is nice and clean, that unit is quite tame compared to many of the killer subs of today, although with some other speakers and not very harsh demands, it shoudl be quite lovely. In other words, do not expect it to show off when playing sci fi movies of planets blowing up; it was intended as a "fill" for modest consumer satellite systems in small apartments or rooms.

It was replaced by the MX700, then the SuperFastDeepBass model of the 700, then thre was a reissue of the 70B with the SuperFastDeepBass higher output drivers.

Now as to your C9's, I'm sorry I am not sure what that is. Are they ported?

Barry

Now as to your C9's, I'm sorry I am not sure what that is. Are they ported?


What what is? You mean not integrating well? I think it's mostly because they are large and have a slightly bolstered response under 200Hz which just gets further amplified in my small room. So, while the 70 does go deeper whist being more solid, there's a lot of overlap, even at the lowest crossover setting. This is really a moot point because I got the sub to use with small bookshelves (which will probably be the Energy RC-10s as I can get them for super cheap and have actually heard them, and liked them a lot).

I'm also trying to score a Rotel RSP-976 or similar older model with bass management so I can high-pass the mains to integrate better. I like the 976 because it has digital in and I don't have a good DAC (or any DAC for that matter) at the moment, especially one that can decode and mix down surround from DVDs. It would also give me the opportunity to go surround in the future.

And I noticed this sub isn't a monster, but it can give some impressive output in my room. And more importantly, it sounds great while doing so. I threw some test tones at it and it can handle down to 30Hz with authority, but when I did 20Hz, I hardly heard (or felt) much before I then heard the distinct thudding of the driver bottoming out. I watched the excursion, and it isn't that much. It's okay though. My living arrangements will probably not facilitate the realistic reproduction of full rocket engines for quite some time.

edit: Oh, and yes the C-9s are ported, both front and back. They're almost 1.5' from the back wall, but I know I'm hearing some boom from them. I don't have port plugs for them (got them used) but again, doesn't concern me as hopefully someone will be kind enough to take them off my hands (to help fund the bookshelves).

edit2: Also, the humming has lessened even more... just since re-setting things up this afternoon. I can't hear it at all now (especially with my computer on and fans making noise) unless I stick my head right up next to it. And I live in Bend, Oregon. Small town. But I do live on a hill which has a bunch of broadcasting towers on it. I think they're cell phone though... I wonder why I'm only getting this problem with the sub and haven't with any speakers I've used before (including my old crappy sony sub I used to have).

My point was, plug the ports. You CANNOT integrate ported speakers with a sub.
What brand are C9's?