Advice Required on 2 Subs

Discussion in 'Subwoofers' started by PUD the Ancient, Aug 30, 2007.

  1. PUD the Ancient

    PUD the Ancient
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    I currently have Atlantic Technology 4200 speakers with a velodyne SPL-R1200 Sub. The speakers only go to 80hz so the Sub is providing all of the low end. My room is 3.5m long by 2.9m wide and about 2.3m high. The Sub is placed in the left front corner of the room about 2.7m from my seating position. This seems to be the best place for the Sub in terms of integrating it properly with the speakers. All other locations I have tried do not seem to provide proper integration although I am somewhat limited on space.

    To me this setup sounds very good with some nice deep and detailed bass, the only problem is that because the Sub is in the left corner I find that I perceive the bass to be coming from this location so the right side feels a little lite at times. My question is would a second Sub in the left corner solve this problem? or would it just create more issues?

    I guess if the advice is that something like this would work, would I be better going for a similar Sub like possible the SPL-R1000 (due to limited space) or should I be looking at something different.

    If someone would also like to comment on the pitfalls or problems incurred by having 2 Subs I would greatly appreciate it.

    Thanks :)

    Paul
     
  2. PUD the Ancient

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    Sorry forgot to ask :rolleyes: how does one go about getting a signal to 2 Subs when my Amp only has one LFE sub out?
     
  3. Member 96948

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    When you say the sound appears to be comming from the left, is it like you can close your eyes and 'see' where the sound is comming from, or do you get a sense of one ear getting more bass than the other?

    I'd be surprised if it's the former, but if it is I'd say it's possibly a case of refing your setup a bit. With a small room like this as headroom is unlikely to be a problem, try lowering the crossover of the speakers to 60Hz.

    The latter can sound like the sound is left biased, but its quite likely that your left ear is suffering from a room resonance that the right isn't. Moving yourself will obviously move the offending ear to somewhere more comfortable, but it is also worth moving the sub too, but I have seen this same issue discussed on HTS and two subs didnt solve it.

    This is a situation that I have some sympathy with as I've tried a number of positions in my room and a number of them have resulted in the problems you have. One position was unlocatable in the aural sense, but I could just feel where the bass was comming from and another gave me the 'in one ear' effect I described above.

    In all, it's about positioning the sub and you rather than introducing another sub.
    Have look here.

    Russell
     
  4. PUD the Ancient

    PUD the Ancient
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    Thanks for the reply Russ. I would say it is as you descibe, the left ear is hearing more bass than the right. Unfortunately due to my limited space I have tried every location that is available for the Sub to sit in and the left corner is the best otherwise integration with the speakers seems almost impossible.

    I notice in your signature that you have a velodyne SMS-1, I have looked at these but I was unsure if it would help me to integrate the Sub better into my room or possibly help with the problem I am having. Any thoughts? :)

    My speakers only go down to 80hz so If I put the crossover at 60hz would that not leave a big hole?
     
  5. Member 96948

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    Duh! You did say your speakers roll off at 80Hz - So many thoughts, such a small brain to store them in. Something was bound to get lost.:rolleyes:

    EQ is definitely worth it - no question. There is a man who at this point has had EQ for only one day. See his thoughts here.

    The SMS-1 has an eight band version of the Auto EQ in your SPL-R. I used it once and realised that unless you're very lucky and the problem frequencies occur at exactly the frequencies of the filters, its not much cop. A nice sales point, but not very effective.

    The SMS-1 is a better buy than another sub in your situation and almost as expensive, but would certainly be far more effective. It is expensive, but it is quality and very, very easy to use and I obviously think it worth the money.

    Others will point toward the Behringer Feedback Destroyer which is certainly a lot cheaper and can be as effective but it is nothing like as slick and lacks the easy access to user definable preset curves, remote control, etc.

    There is an independent shootout between them here.:D

    Russell
     
  6. PUD the Ancient

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    Thanks very much for the help Russell, I really appreciate it.

    Thinking about it there is one thing I could try with the Sub placement, I could swap the Sub and left speaker around so the speaker is against the wall and the Sub would be on the inside edge of the speaker away from the wall. I had been reluctant to do this as my speakers sound spot on at the minute and I was not keen to disrupt this, but probably worth a try. There is only a couple of feet in it but do you think doing this might help?

    I think it will also be worth getting a SMS-1 on order next week. I presume when setting up the SMS-1 I would first reset my SPL-R1200 EQ to defaults and let the SMS-1 do the work?

    Thanks again for all the help.

    Regards

    Paul
     
  7. Member 96948

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    It's free to try positioning changes, so why not? You can always put things back with no harm done. Honestly, I'd expect the speaker to sound a bit 'shouty' that close to the wall, but experiment with toe in angles and see how it goes.

    EQ is there to sort out all the problems that can't be solved with positioning first. But as you will find, once you have the SMS-1s on screen display, it's a lot easier to see if your positional changes are moving in the right direction or not.

    And you're quite right, set the SPL-R back to flat. Everything it can do is repeated on the SMS-1. If you have any auto setup room EQ routines on you amp, make sure they're set to off as well.

    Give us a shout once you get the SMS-1. I have a really good idiots guide to it's use. Sorted me right out.:)

    Russell
     
  8. PUD the Ancient

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    Thanks again Russell. I also would not expect a good result from having the speaker that close to the wall. Why would I switch off the EQ on my Amp, surely that is only affecting the speakers? the only setup it does for the Sub is distance and level which usually needs to be adjusted with my SPL meter and tape measure anyway. Are you saying switch off the Amp EQ permanently or just while I setup the Sub? Sorry if these are silly questions as I am a bit new to all this Sub calibration.

    Thanks

    Paul
     
  9. Member 96948

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    What amp have you got?

    Russell
     
  10. PUD the Ancient

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    I have a Pioneer AX5i.

    Paul
     
  11. Member 96948

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    Pioneer's MCACC should perform corrections for speaker size, distance, SPL and frequency response to all channels including the sub. As it's the one channel that suffers the most from room related effects, it would be the worst one for MCACC not to EQ.

    As you've already noted the inaccuracies in distance and SPL levels, there's no reason to suspect that MCACC is getting the frequency response right either. Audyssey MultEQ XT, it ain't, but even that's far from fool proof. Like most 'automated' EQs, it requires a level of user knowledge to extract the best from it, or at least stop it from comming to the wrong conclusions.

    I find it's best to get the best EQ solution you can with the SMS-1 first and then run the auto setup. That way, you're giving MCACC the least work to do which should avoid the most cock-ups. You can always dial in extra/less EQ to get the resulting curve to suit your taste rather than Pioneers.

    BTW, with Audyssey, I've stopped altering all of the distances it comes up with. These systems measure the effective distance of the source of sound, not the actual distance. This is important because the crossover in a speaker and even the variations in each drivers impedance can cause large phase shifts which are analogous to distance. In other words each speaker has an inherant delay of it's own that needs to be taken into account.

    If you have three speakers across the front that are the same, then the apparent distance 'error' should be very similar. If it is, then that's fine. Only experience with running the setup and the results it generates, will give you a feel for what's right or wrong.

    Also worth noting is that the SMS-1 introduces a 2.5ms processing delay. This will result in an additional 60 to 90cm being added to the subs distance.

    Russell
     
  12. PUD the Ancient

    PUD the Ancient
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    When I have run the Auto setup for the speakers in the past I have always had to make some minor adjustments to the levels with my SPL meter. Although the Amp does not seem to offer any adjustments to the Sub as it does with the speakers and this is why I had assumed it was just doing a basic setup. the only setting available for the Sub seems to be 'Bass Peak'.

    So basically what you are saying is disable the Pioneers EQ, setup the Sub using the SMS-1 and then run the Pioneers EQ and make any neccessary minor adjustments? Also are you saying I should stick with the distances the Pioneers EQ decides on? I presume that when I run the setup on the Pioneer it will take into account the extra delay with the SMS-1 in the chain?

    I had a quick read through the manual for the SMS-1 earlier and I have to say it all seems it bit complicated for someone new to Phase and crossover etc, but I am sure a bit of trial and error will get it done.

    Thanks for being very patient with me.

    Regards

    Paul
     
  13. Member 96948

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    I can't see the point of EQ if it doesn't do the subwoofer. It's the channel that is guaranteed to require EQ the most. Pioneers Flash demo on there website indicates that it does the same for all channels. I suppose the proof is in what, or how many tones it runs through the subwoofer, if it's the same as the speakers, then I'd say it should do the same. Of course, there'll be an utter font of Pioneer knowledge on the Pioneer Owners Forum. I'd ask there.

    Yes. Yes but use some common sense. Yes.:thumbsup:

    It'll become a lot easier once you have the SMS-1 and are using it.

    Her Majesty has given me 17 years to be patient with. Take advantage of it.

    Russell

    PS. That last bit is obviously not true. It's 8 years with good behaviour.
     
  14. PUD the Ancient

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    Thanks Russell :thumbsup:

    I will give you a shout again when I have the SMS-1 and I am all confused :rolleyes:
     
  15. Caralfa

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    Paul, it might sound daft to some people but have you ever had your ears and hearing properly tested ? It's amazing how many people believe that they have 'perfect hearing' when in fact they don't. Even just a small amount of wax in one ear can make a huge difference to what you actually hear and that's before you start taking room acoustics and furnishings into account. Very few people have exactly the same range of frequency hearing in both ears . What can sound perfect to one person is far from perfect for someone else. :lesson:
     
  16. PUD the Ancient

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    Actually I did have a problem a while ago with wax in my ears but that has been sorted now and I follow strict advice given to me by my doctor about how to keep them clear. I am getting old now and the eyesight is going (glasses) and various other aches and pains, infact the hearing is about the only thing that does work at the moment ;).

    Thanks for the advice though :)
     
  17. Nimby

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    A quick check of your hearing is to lift the receiver then change from one ear to the other with a fixed line telephone.

    How many of you can hear exactly the same tone in both ears? :)
     
  18. Member 96948

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    I know I can't.

    Russell
     
  19. PUD the Ancient

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    Russell,

    Would getting a new Amp with Audyssey MultEQ XT be an alternative to getting the SMS-1 to help with the sub problems I am having?

    Thinking about a new Amp anyway, so just wondered.

    I also wondered about the SMS-1 running 2 subs, when you are setting up the SMS-1 with 2 subs attached obviously the bass would be coming from 2 locations so would that make the EQ process harder to get a flat response.


    Thanks

    Paul
     
  20. PUD the Ancient

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    Can anyone answer these questions?
     
  21. dts_boy

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    thats a very good question - i've been looking at the sms1 for a while now as well. have a decent processor which i dont want to change just yet but am eager to improve my bass performance, looking at new subs right now for the answer but haven't come across any with built in eq so the sms1 is nice for the money i think...
     
  22. PUD the Ancient

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    I have been moving my Sub around the room all weekend to try to get it integrated with my speakers but I just can't seem to get it right. It seems to be worse than ever now, a bit boomy and out of sync. I am not sure if I should get the SMS-1, a DD10, a new Amp or some professional help.
     
  23. Member 96948

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    It would help, but is not capable of anything like the cuts/boosts that the SMS-1 can offer plus, it doesn't offer any manual control over the resulting EQ curve. You can't actually target a problem with it - you can only run it and see what happens.

    Then again, there is the bloody marvellous Audyssey MultEQ XT Pro Sound Equaliser which Phil Hinton reviewed here. £2k may put you off.

    The SMS-1 does not know whether there are one, two, three or four subs working. It simply reads the combined output as it registers at the end of the microphone. It can't tell you if the bass is suffering from weird directionality problems or any other spacial information - It simply gives a frequency response at that point in space.

    If you're going to run two subs though, you don't need an SMS-1 as you'd just slave on DD to the other.

    Russell
     
  24. Member 96948

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    All of the SVS subs (above the NSD range) have a single band PEQ, whilst all of the Velodyne DD series pack a built in SMS-1 as standard.

    Russell
     
  25. PUD the Ancient

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    I am not quite sure what to do at the moment, I clearly have a problem which I am unable to resolve. I think its best to probably stick with one sub at the moment so not to add to my problems. I am unsure if I should get an SMS-1 or just go the whole hog and get a Velodyne DD-10.

    I guess I am just a little worried that I will spend the money on either and it will not resolve the problem.
     
  26. Member 96948

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    At this price level, that is certainly a concern.

    Can you dealer do nothing to help out with a home demo?

    Russell
     
  27. PUD the Ancient

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    I am not sure at the moment but I do not think so, I will hopefully be speaking to them again Tuesday. I begin to wonder if there is something wrong with the Amp or Sub or perhaps I just have a really nasty room. I presume it is possible I could have a room that even something like an SMS-1 could not fix? and that is what worries me.
     
  28. Member 96948

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    I really don't think it's that drastic.

    Just for the sake of experimentation, have you tried moving the sub out in front of both the front speakers? Have you tried pulling your seat forward/sideways by a foot?

    I'm not saying if it works leave it there, but if it does work you'll have learnt something about your room. Only if that doesn't provide a result should you be looking for a technological fix.

    Russell
     
  29. PUD the Ancient

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    No I have not tried that as it never really occured to me as that is just not a place the sub could permanently be (tripping over it every five minutes ;)) . At this stage anything is worth a try so I will try to it sometime this week. I am very limited on space and I have already tried moving my chair to all available locations.

    Are you saying that if moving the sub to this location works then the SMS-1 woud likely be able to help with my problem?

    Thanks Russell :thumbsup:

    Paul
     
  30. Member 96948

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    Quite possibly as you will have removed an unfavourable room node from the vicinity of the troubled ear.

    However there was someone on Home Theatre Shack who had a room that just sounded 'left'. Far greater bass minds than are collected here applied their knowledge to it. Nothing solved it and he just got used to it.

    Russell
     

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