Does the Markbass LMII use a built-in compressor/limiter?

Discussion in 'Amps and Cabs [BG]' started by on1ne, Jun 20, 2008.

  1. on1ne


    Dec 21, 2004
    Played out with my LMII/ GS 112 Aguilar rig last night. I use a foam mute and flats on my P bass to get the old school short decay thump. On some tunes I could swear I was hearing that sort of swelling sustain that I usually associate with a compressor/limiter. Was not using any effects box and there was no DI or mic thru the PA. My imagination?
  2. I assume there is an output/safety limiter on the LMII like most every SS amp. However, there is no input limiter that would result in what you are describing.

    It might have been a resonant frequency in the room that was causing certain notes to 'bloom' a little bit.
  3. dave_bass5


    May 28, 2004
    London, UK.
    I agree. Ive hear that a few times when playing on wooden stages using my UL212.

    There is a limiter between the EQ section and the power stage but that just seems to be there to stop any clipping in the power section. As ken said, there is no control for it.
  4. B String

    B String Supporting Member

    Apr 11, 2002
    Los Angeles
    A ha!!!! See Ken??
    You guys thought I was nuts, but I'm not.
    Sometimes when I'm slapping at higher volume, or when the
    input gain is a little high, I get some big time compression
    squashing on the top end. Thank you.
  5. dave_bass5


    May 28, 2004
    London, UK.
    Maybe your both nuts ;-).

    One of the only things i don't like about my MB heads is that once i go past 1 o'clock on the master i know i wont get any more volume out of my head. It just seems to get more compressed.

    I must admit i dont play at that volume much (will do tomorrow though, hope my 1212L can cope ;-)
  6. He wasn't talking about that... he was talking about 'volume bloom'... i.e., an increase in volume of some notes.

    IME, the quashing you are hearing is the small cab compressing when you really dig in. This is a classic issue with trying to push too much air out of a 112 or 210 at high volumes, and IMO and IME will become more apparant using a technique that produces strong peaks (like slapping). I've had my old 210UL almost sound like a compressor totally clamping the signal with a variety of heads:D and playing louder than I should have been with that little box. I've had less of that with my Berg 210's, I assume due to the more mid present voicing and somewhat attenuated low end versus the Epi210UL and most 112's I've used as stand alone.

    Trust me, there is ZERO compression with the LMII/F1 run at 4ohms into a large cab like a 410.
  7. B String

    B String Supporting Member

    Apr 11, 2002
    Los Angeles
    For the most part, I agree. Although, I can get that same
    effect by putting the nput gain a little too high with my
    active Fender.
  8. +1... any well designed SS head will eventually stop getting louder and compress versus totally farting out. IMO, this is good design.

    And remember, the absolute level of the master is arbitrary. Depending on the amp and your input signal strength and playing technique, various amps can reach their full usable volume at vastly different levels (9 o'clock to 3 o'clock or more!).
  9. +1 clipping the input will result in some not so very good things. The MB stuff, from what I was told, has the clip light set to come on right when things start to go bad (this is what my ear hears also). Some other heads use the clip light as an 'early warning system' and it's OK to have the clip light come on somewhat regularly.

    With the MB, the design seems to suggest finding the hardest lowest note where the clip light just comes on, and then backing off a bit.

    This is just a touch different from other designs. I don't really have an opinion on which approach is better. I again run my MB heads so that the clip light never comes on, with the gain knob just below that threshold (for my basses and technique, that is usually between noon and 1 o'clock).
  10. All of the above being said, it would not surprise me if the output limiter would also clip in when running the LMII or F1 hard at 8ohms into a small cab... it's easy to run out of headroom and also to get that 'woofer compression' thing going all at once.

    It is strange, almost sounds like a compressor/limiter set too high... things just start 'not getting louder'. That's the time where tweeters blow!

    Again, IMO if you are experiencing this regularly, time for a bigger cab!
  11. Ezbass


    Apr 3, 2008
    +1 This is exactly why I've changed from Ashdown to MB, open up the Ashdown and it farts at about 2-3 o'clock, open up the MB II and just nice and clean. If I want distortion I'll add it with my MXR M80 where I can control it.

    Interesting about the speaker compression, I guess that's the price you pay for small compact cabs.
  12. on1ne


    Dec 21, 2004
    so it may be the cab and not the head?

    I thought they would be a good match. The LMII rated at 250w/8ohm and the Agui GS112 8 ohm cab is rated to handle 300w.

    This is the first time I pushed them. I'm curious to know how and why a speaker cab itself "squashes" the signal. I would have expected it to just start farting if it's being given too big a job. Have to admit I'd rather it did squash as opposed to those nasty farts.

    If it is the head, I'm surprised since the band wasn't all that loud. I test drove both the head and cab before buying but in store testing can only tell you so much.

    I don't want to go with a bigger cab since the whole point was to downsize for getting around in NY City. I got a second Aguilar 12 which I only expected to need for bigger gigs than this one. Hopefully the 2 GS112s together will deliver enough.
  13. lefty007


    Jan 19, 2004
    Miami, FL
    I got an LMII going in a Schroeder 1212L and I get the same thing, a bit of compression when pushing it really hard. . .

    Not very musical, but expected given the size and specs of the componets in question.
  14. Now I'm confused. I thought you said you were getting an 'increase in sound' from some notes?

    Regarding a single 112, I've never been able to do anything but small gig with a single 112, since I like a full deep sound. Of course, if you like a very midrange tone, a small single cab will do just fine. If you put 1000 watts into that single 112, it wouldn't get much louder than a good, honest 300 watts. With a big cab that can handle the wattage without that thermal overload thing, a few hundred more watts can make a HUGE difference in open low end and 'non compressed' sound... not necessarily hugely louder, but just more even, less stressed, deeper cleaner lows, etc., etc.

    Two 112's is an entirely different thing... more wattage from the head, more cone area, coupling.... MUCH more volume and low end than the sum of its parts. Two GS112's and the LMII will kick! I run a 4ohm 410 with the LMII, and it just thunders.

    Regarding matching a speaker to an amp, the wattage is pretty unimportant at that level (i.e., a single small box).... 100 watts or 1000 watts, there is just so much sound that you can get out of that little box.

    I'm not an EE, so compression might not be the right term, but eventually, a high quality cabinet (112 or otherwise) will just stop getting louder. A good one won't totally fart out, but will 'compress'... by that I mean it will just stop increasing in volume. Of course, if you have huge watts going into a small cab, you can fart anything out.

    Assuming you are now talking about 'running out of volume' with the GS112/LMII, adding a second one will fix the issue for all but the loudest, largest gigs IMO.
  15. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Ya, if you're playing loud enough to make a Aguilar 12 fart out, you need another cab. Sometimes people just ask too much of their smaller equipment, and I think you're doing so.
  16. on1ne


    Dec 21, 2004

    The sound was rather like a compressor where the initial attack is somewhat softened and then there is a sustain which kind of "blooms". But the volume wouldn't exceed a certain level and cranking the level at any point in the signal didn't make much difference. If anything, cranking up further just increased the perceived swelling effect but not the overall volume. That's exactly why I thought of a limiter/compressor.

    Assuming that the LMII is not to blame, I'm still curious to know what is happening to the speaker that would cause it to act like a compressor when it's pushed as opposed to just farting out.

  17. You'll have to talk to an EE type about that. All I can tell you is that it is not the head. You will find this phenomenon when pushing any very small, high quality cab with a reasonable amount of watts to its limits. If you didn't, all of us carrying around 2 x 210's and 410's wouldn't do that... we'd all be using a little 112:)

    Edit: I'll put out a call to Alexclaber, who knows the ins and outs on this stuff.
  18. Ezbass


    Apr 3, 2008
    I think you'll find that the LMII is rated 300watts for an 8ohm load, at least that's what it says on the website
  19. on1ne


    Dec 21, 2004
    If anything that would imply an even better match between the LMII and the Aguilar GS112

    from what I read here it seems that the single GS112 wasn't up to the task of filling the room. That's OK, I have the second GS112 and I'm sure the 2 together would have covered it.

    I knew the room was possibly going to be a challenge for the rig but I expected to hear the classic distortion "farting" if the cab was being pushed too hard. I'm still curious to know more of the what and why behind this compression effect when a speaker gets pushed too it's limit. Is it some kind of built in safety mechanism or is it just the way this particular speaker reacts?

  20. I sent a PM to Alex. He's across the pond, so it will be tomorrow morning before he probably posts. He will be able to put the right terms to this (the heat versus excursion limit stuff)... or explain why what I think I'm hearing might not really be what I am hearing:D

    Billfitzmaurice would also be able to provide an explanation or clarification or correction to what I'm talking about.