Sub getting swallowed up

Hello, I recently purchased the polk A9's , A3's and the CSI A6 center. Pushed by an NAD 275BEE and NAD T278. The problem lies with the sub, a MartinLogan Dynamo 700W cant seem to keep up. I like my sub on all the time, 2ch etc. The A9's dont really have the lows I was fully expecting and at lower volumes the sub is ok I guess but at higher volumes it gets totally swallowed up. The bass response, for lack of a better term, is sloppy and unorganized and easily noticeable thats its trying to fit in with the cool kids but cant quite pull it off. Is there an alternative that can stay in the race with the other speakers? I changed placement, made adjustments all over the place and the results the same. The room is about 15x20. Any ideas or thoughts? Thanks in advance.


  • Welcome to the forum
    How large is your listening room?
    Have you considered using more than one sub?
  • I see you edited your post.
    You should definitely consider using multiple subs in a room that size.
  • Overall Im not impressed with the MartinLogan Dynamo 700W in general. Would you suggest another one of the same or 2 different ones. What if anything do I need to run an additional sub off my existing set up? Thank you
  • codycatalist
    codycatalist Posts: 2,661
    SVS is encouraged around here a lot.
    Just a dude doing dude-ly things

    "Temptation is the manifestation of desire which equals necessity." - Mikey081057
    " I have always had a champange taste with a beer budget" - Rick88
    "Just because the thread is getting views don't mean much .. I like a good train wreck doesn't mean i want to be in one..." - pitdogg2
    "Those that don't know, don't know that they don't know." - heiney9
    "Audiophiles are the male equivalent of cat ladies." - Audiokarma Member
  • You can change brands or get another of the same and put them in opposing corners of the room. Two subs (*or more*) can work in tandem to more evenly spread the low bass frequencies around and better deal with the standing waves in the room.
    ALL rooms have standing waves which result from the very long wavelengths of low bass frequencies (*measured in feet*) interacting with the three physical dimensions of the room. In some places they can augment the bass at certain frequencies. In some they can reduce it and it others they can completely destroy it. Every room is different.
    All you would need is a Y adapter if you only have one sub out.
  • Nightfall
    Nightfall Posts: 9,500
    SVS, HSU, and Rel.
    afterburnt wrote: »
    They didn't speak a word of English, they were from South Carolina.

    Village Idiot of Club Polk
  • hendon1971
    hendon1971 Posts: 11
    edited August 2016
    Make total sense. Thanks for the advice. another sub may be what I need. SVS appears to be a monster. WOW.. May give it a try. Really dont have the room for 2. Was gonna try and make room but with the SVS it looks like 1 will do. Thanks again
  • @hendon1971 I have set up systems and currently have two in which two smaller subs do a far better job of getting the bass out into the room more evenly and with greater overall output than one large sub. ESPECIALLY in the lowest octave (*40hz and down*)
    Again it's them dang standing waves in your room!!! :D
  • After fooling with that dang sub for what seems like hours again last night I just cant put my finger on the issue. The bass is sounding horrible not smooth and clear. Distorted and unorganized and no matter the setting or where I place it. I can pick out exactly where its at. Sounds bad at all levels and settings. I've read and heard all great reviews on it but I dont see it. I wont talk bad about any brand because im sure it has its place in certain systems. Unless im overlooking something it def does not work with the system I have. My other sub from by box system was in all the same places and sounded perfect. SVS mat be in the very near future.
  • msg
    msg Posts: 6,600
    What kind of volume are we talking about here? (either vol number or dial position) This sub does seem on the small side for the rest of the system/room. If you're pushing it too hard, it's going to be less controlled, and won't be able to keep up, and it will perform and sound just like you're describing.

    I've read of some small subs packing a wallop, but they're usually of very high power and single main driver and one or two passive bass radiator designs. Mostly though, like the other guys have said, SVS, HSU, etc. I use one large HSU VTF-15 for a large-ish room, and it does well, though even with that, I can see where adding another sub would be beneficial. However, placement, space, and cost are factors, so we make concessions where necessary.

    To be sure, we could use a little more info on the system settings
    1. Where are your speaker and sub levels set, and on what scale?
    2. Which AVR/Preamp are you using? I can't find any info on an NAD T278?
    3. Does it offer bass management?
    4. What do you have the crossover set on? (80Hz or 70Hz for starters; in your case, probably less)
    5. What is the system volume when things start to deteriorate?
    6. What are the physical settings on your sub (photo of the amp plate would be beneficial)

    My guess is that the sub is too small for the room and A9's, and is being pushed too hard, especially if you're crossing at 80Hz.

    When I was first shopping systems a few years ago, I heard both the 10" and 12" ML Dynamo models at a local Best Buy. It was my first experience with subs, and I thought the 10 sounded great in the demo room. Until they switched to the 12. Even just 10 to 12 was night and day - the 12 had obviously greater output, impact, went deeper, offered sustain where called for, and sounded more relaxed. As HSU says, you can never have too much sub. As the other guys have offered, go bigger here.

    For now though, you should still be able to find a reasonably comfortable setup with what you have. It's easy to lose yourself in troubleshooting so maybe take a step back, come back in after a break, and zero everything.
    • Start from scratch with just the two mains and the sub.
    • Try crossing to the sub at 50Hz or 60Hz and see if the sub cleans up. With your amp, the A9's should be able to manage 50Hz - 60Hz no problem, but don't go too crazy on the volume knob.
    • I'd say -20dB to -15dB max with your current amp to keep it comfy and safe without having more info on what kind of current that amp is pushing.
    • RTi/A speakers, especially the 9's, can suck all the power and current you can give them, and can be authoritative and impactful, but blanket convention on these speakers is 200wpc with a high current amp for starters, so watch your volume with lower power/current so you don't toast anything. If you actually hear obvious distortion, you've gone too far, so back it down and accept your limits, or add more power.
    I disabled signatures.
  • hendon1971
    hendon1971 Posts: 11
    edited August 2016
    NAD T-758 and NAD C 275BEE. Sorry for the typo. The sub really dont fit in at any volume level. Kinda does its own thing all the time. The room is really not that big. I'm going to take your advice and stand back and start over from scratch. Im frustrated at this point anyway. I really appreciate all the thought that went in to your response everything makes total sense. Thats ALOT more incite than I had before. I guess thats the reason I came to the experts. THANKS!! I'll post of any changes. Round 2..
  • msg
    msg Posts: 6,600
    Ah, okay, that makes sense. nice AVR.

    Yeah, so take a run through the stuff above if you feel inclined, and play with it without the system calibration and see if you can get it decent with some basic and minimal configuration as detailed above and see what you think.
    I disabled signatures.
  • After many hours of fooling with settings and different placement I've concluded that this sub is def not the one for my system. Im taking the advice here and going with an SVS sub. I know there are ALOT of variables in play here. The room size is closer to 15x18 and I have the room for one or 2 subs. I'm not sure if I should go with 1 or 2. i do like alot of good clean hard hitting bass throughout. Sorry if I'm not as informative as a lot of the experts on here, Im a Budget is around $1200. Any ideas or advice?
  • SVS makes excellent subs. Otherwise they wouldn't have so many fans here on the forum. Again two smaller subs can do a better job than one larger sub. I've even seen information and reviews in the audio rags recently for up to four!
  • msg
    msg Posts: 6,600
    Hehe, yeah, you didn't really answer any of the questions for anyone to get a proper sense of how your system is set up, so there's no telling what's going on aside from a small sub.

    A larger sub or two will definitely make a difference, but for the best results you're probably going to have to dig in and learn how to set up your system, in general. Or you can just wing it and hope for the best.
    I disabled signatures.
  • K_M
    K_M Posts: 1,602
    Most subs are run too loud. At low volumes they sound kinda okay, but as the overall level is increased it become boom and annoying.

    Its hard to diagnose a room online, without hearing it.
    Lsi15, Lsi9, LsiC,Rta11t,M5jr+,M4, SDA SRS 2.3TL, Rti6....Still listing stuff, a work in progress.
    Electro Voice EV-SIX
    Advent-Now gone
    Yamaha A-S801
    Yamaha RX-V377
    Yamaha RX-A860
    Yamaha RX-A3060
    Harman Kardon Hk-350i
    Harman Kardon Hk-........
    Harman Kardon PM-665
    Harman Kardon HK-775
    Pioneer.......Stereo Receiver

  • mikeyb128
    mikeyb128 Posts: 2,886
    Buy the biggest baddest sub you can afford. Then later on down the road get another one. Forget buying two lesser subs as they will not outperform 1 big nice sub if integrated into your system properly. 2 small ones will smooth frequency response across a larger seating area, and help to avoid nulls and humps. But I would take one bada$$ sub over two lesser ones any day of the week.
    2 channel:
    Bryston 4B3, Bryston BDA3, Cary SLP05, Shanling CDT1000SE with parts conneXion level 2 mods, Nottingham analogue ace space 294, soundsmith Carmen MKii, Zu DL103 MKii, Ortofon MC 20 MKii, Dynavector XX2 MKii, Rogue Audio Ares, Core power technologies balanced power conditioner, Akiko Corelli power conditioner with Akiko Audio HQ power cable, Nordost heimdall 2, Frey 2, interconnects, speaker and power cables, Focal Electra 1028 BE 2, Auralic Aries Femto, Black diamond racing cones, ingress audio level 1 roller blocks, JL Audio E110 with Auralic subdude, Primacoustics room treatments.
    Focal Aria 926,905,CC900, SVS PB ultra x2. Pioneer Elite SC85, Oppo BDP93, Panamax M5400PM, Minix neox6, Nordost Blue heaven LS power cables.

  • @mikeyb128
    You just made my point for me ;)
    Large subs have great output and all,but have much lower WAF (*Wife Acceptance Factor*) and can be harder to place properly. I have absolutely nothing against large subs (if ONLY I could get my greasy grabbers on a JL Audio!) but they don't always work in everyone's rooms/living situations.

    No one said anything about using two "lesser" subs.
    Just two smaller ones.
    There are MANY smaller subs out there on the market capable of amazing output. Thank Bob Carver for this..........
  • SCompRacer
    SCompRacer Posts: 7,220
    Don't forget about bass traps.
    Make yourself necessary to someone. Ralph Waldo Emerson

    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ & Pro 11+ * Signature Series Sonore Music Server w/Deux PS* Twisted Pear Buffalo IIISE Pro ES9038 DAC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *

  • Just pulled the trigger on 2 SVS PC-12 Pluses . Mainly to space limitations. Many thanks to all for the expertise. We'll see what these rascals can do. Update in due time.