Is it possible my room is too small for Mirage BPS-400? How do I calibrate my setup?

Discussion in 'Archived Threads 2001-2004' started by Chris PC, Jul 23, 2002.

  1. Chris PC

    Chris PC Producer

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    I have had this subwoofer for a year, but usually only use it for movies. For whatever reason, I find that using my front main speakers alone as large tends to give me the best sound for music (not comparing source direct or not, just no subwoofer no matter what with fronts large). I have tried tinkering with the subwoofer placement in order to see how I can get the sound to be better than just using the fronts, but apart from hearing more bass, the sound isn't better. The sound is muddled and just not to my liking. I will continue to test. I put the subwoofer in the corner again, but it sounds worse than where I had it 1/2 way along the wall. I have tried with the 100 hz crossover in the Marantz only. I've tried with the receiver crossover and the subwoofer crossover set at its max of 100 hz. I've tried fronts Large and Sub= Yes but that never sounds "good". I have even tried fronts Large and Sub=Yes with the subwoofer crossover set at 50 hz. I sounds different, but never better. When listening to my fronts alone, I do notice that the sound doesn't go as deep, but I can really hear articulate bass and it sounds good. After listening with the sub and then going without, it sounds really thin, but after I'm adjusted I hear things I couldn't hear with the subwoofer. With my subwoofer in the room, I don't hear much range in the bass notes. I can't find my test tone CD to tinker with placement, but without an EQ, I'm just basically changing placement. How do I set the subwoofer level for my system? I am actually happy with the way the front speakers sound alone, so I'm listening to music that way now and will continue to listen this way, but I wish I could use this subwoofer and take advantage of its potential for deep clean bass.
    Would I be better off with a "smaller" subwoofer?
    Here is my equipment:
    Marantz SR 6200
    PSB Image 6T front speakers (9C centre and 2B surrounds not used for stereo listening for the most part)
    Mirage BPS-400
    Room: 12 feet by 14 feet 4 inches and a drop ceiling of office tiles at 7 feet 1 inch. Real wood ceiling is 1 foot higher. 2 concrete walls and a concrete floor with underpad and carpet. 2 cheap panel walls that don't go up to the ceiling (only to the drop ceiling) which results in hearing bass in the other room, not just bass through a crack under the door or through a wall, but actual bass that sounds like you're in the same room.
    Room configuration:
    12 foot long wall near entrance has door at right most side (right from the viewpoint of facing into the room) and bed is along same 12 foot wall to the left of the door. opposite 12 foot wall has 32" TV on 45" wide stand and PSB 6T speakers on either side. In the right corner, there is a 32" wide dresser. This will be moved to the right side 14 foot wall which now houses my book/video stand. I will also be moving the TV stand away and using either a table or the subwoofer in its place. In place of the dresser I will put my old vertical stereo stand back into use and even prop it up on a table if need be. The end result will be that I will have lots of flexibility for subwoofer placement. I will be able to put the subwoofer in the left corner (all 3 concrete surfaces (walls and floor)), in the middle under the TV, which is between the two speakers, in the right corner (panel wall and concrete floor and concrete wall, or along the left side concrete wall. I will try to take some pics and post a link somewhere.

    __________
    S P..S..P S
    S
    S
    S
    __BED_DOOR
    Above is an attempt to show my subwoofer placement options. Possible subwoofer placement is shown by the S's and the P's are my front PSB 6T speakers. The periods are just to help format the spacing. Bed and Door are not to scale [​IMG], as the bed is more or less along the centre of the wall and the door is in the right most corner of the room. So I do have a good degree of flexibility in choosing subwoofer location, but if placed in the corner, there is very little room for adjustment. If the subwoofer is in the corner, I can't have it away from the walls more than 6 inches or so. Placing between the PSB speakers is not an option quite yet, but it will be possible soon, but right now my TV is sitting on top of my 32" wide IKEA TV cabinet. I might build a small table for my TV for now or put the TV on the subwoofer. I want to try it because I suspect it might be one of the best places. Along the centre of the wall and between my PSB 6T's might be the best location. I was planning to get an AE100, so the TV might be going anyways.... [​IMG]
    OK, so how should I attempt to calibrate this thing? Should I use my test tone CD's to check frequency response again with the subwoofer in different locations? Should I get the response of my front speakers too? Should I place the subwoofer where I sit and walk around to find potential good positions for bass first? What should I do and in what order?
    Thanks for any help and advice [​IMG]
     
  2. Chris PC

    Chris PC Producer

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    OK, another long post by me, but at least someone could start by giving me some advice as to whether the subwoofer could possibly be too large for the room size? I heard someone say it is too big for small rooms. Maybe the gain of a small room of the size and shape of mine is just not suitable for a bigger subwoofer?
     
  3. ChrisAG

    ChrisAG Supporting Actor

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    I'm definitely not an expert in bass matters, but I found that proper blending for music meant that I had to turn my sub down a bit. Maybe you have the sub turned up too high?

    Have you tried putting the sub against the front wall, behind the PSBs?

    I'm not sure putting the sub under the TV is a good idea - wouldn't the vibration affect the picture?
     
  4. Wayne A. Pflughaupt

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    First of all, Chris, until you find your test tone CD and take some readings of both the sub and the mains (to fully understand what is happening in your room), moving speakers around and guessing is about the best you can do.

    You’ve been hanging around here a while, so I’m sure by now you know that you will never get optimized performance from your sub until you equalize it with a dedicated parametric EQ. After you do this it will be much easier to blend your subs and mains.

    Actually, I would prefer too much sub to too little. You can always turn it down, roll out the low end, etc., but you can’t increase the performance of an undersized sub.

    Regards,
    Wayne A. Pflughaupt
     
  5. Chris PC

    Chris PC Producer

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    ChrisAG,
    So you're subwoofer is blended ok in your system? Do you use it for music? I recall you used your mains for music alone mostly.
    Wayne,
    I don't really believe 100% that my subwoofer is TOO BIG. Its just a possiblity I thought of because I heard people say huge subs and small rooms aren't always good. I just didn't know how to explain it. I guess with a "smaller" subwoofer, you have output that rolls off from between 30 and say 16 hz but your room makes up for that because there is room gain. I figure that small subwoofers work ok in small rooms because although their output is rolling off down there, the room compensates and you break even with decent output approaching 20 hz, depending on the subwoofer of course. My subwoofer, however, is capable of very high output right down to 18 hz, so I figured that, the combination of the gain in my small room and the subs high output down low might be causing problems.
    So I am re-arranging my room now so that I have a large number of placement options. Then I will grab my test tone CD's and go to work measuring the front speakers alone and then I will measure and calibrate the subwoofer level to match and see how I do from that.
    I guess the thing is that, I don't hear clean bass down there. Its quite muddled and won't blend well with my mains. Although my mains don't sound loud at 40 hz and below to their limits, like I said, I could hear distinct articulations. With the subwoofer on and the fronts set to small, I no longer hear those articulations, and much of the subwoofers output is muddled. I wonder if a bi-polar subwoofer isn't such a good idea in a small room. I wish I could compare it with a Servo 15 or a PSB Stratus Sub 7 or SVS subwoofer, but I can't.
    Thanks for the helpful advice. I'll keep cleaning and re-arranging/simplifying my room and get to work with the test tone CD's and my RS SPL meter [​IMG]
     
  6. ChrisAG

    ChrisAG Supporting Actor

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    I've tried using the sub for music on occasion, and it sounds quite good. I'd rather use Source Direct, but since putting my mains on the concrete slabs to improve clarity (to increase their height because of the couches that obstruct part of the woofers) I have lost some bass. I may try filling the balast chambers to see if that helps.

    BTW, this is off topic, but during the heat wave last month and the resulting power outage in Toronto, I lost my VCR. I opened it up to check the fuse but it was intact, so I assume something else inside got fried. To make sure this doesn't happen to any other component, I picked up the Monster HTS2000 power bar from Bay Bloor. Are you running any surge protector?
     
  7. Chris PC

    Chris PC Producer

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    Good idea. Nothing protects from lightening, but I should get a surge suppressor. I have my TV, receiver dvd cd and LD all on wall switches and they are all connected to a "power bar" that has a "fuse". My vcr is plugged right into the wall. We've never lost anything here due to spikes, but I should get some surge protectors. The wall switch is nice though. With all my equipment turned off AND the wall switches OFF its kinda hard to imagine them getting a surge from power. Lightening can do anything it wants, however, leaping any gap, and destroying even the very best surge protector. I guess the individual electronic device determines the current, but with lightening able to put 1000's of volts through your home circuit, you are at the whims of the thunderstorms [​IMG]
    I have been testing my subwoofer today and it really sucks in the corner. Something fishy is going on with phase and I'm hoping its not got to do with my fronts being ported and the subwoofer being sealed. I have put the subwoofer beck where I had it before for now. It sits 8 feet out along the left side wall. So far that is the best sounding place for it. I will ditch my TV stand for a table and stick the subwoofer there very soon because I am suspecting and hoping that it sounds best there [​IMG]
    Gotta find those test CD's. I know they are here somewhere.
    Hey, can you guys verify something? I could have sworn that the Marantz SR 6200 subwoofer output is not rolled off above 100 or 120 hz or so, so I have resorted to using the Mirage subwoofers 100 hz crossover setting, otherwise, the subwoofer has tended to sound bad. Can someone verify whether there is a crossover in the Marantz that are rolling off the freuqencies above 100 hz that are sent to the subwoofer? Or should I keep using the Mirage subwoofers 100 hz crossover?
    I just swapped back to not using the subwoofers crossover and it sounds ok. Not sure now. The subwoofer is back where I had it along the left wall, but now I find that turning it 90 degrees, so that one woofer faces the wall and the other faces the room, seems to sound better. Hmmm. Will keep testing. [​IMG]
    thanks guys [​IMG]
     
  8. Michael R Price

    Michael R Price Screenwriter

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    There's no such thing as too powerful of a subwoofer. Chris, I think you may have a room response problem. This would be exacerbated by overlapping the output of the sub and your mains (you would then have 3 sources producing the 30-100hz bass, which could cause bad interactions). I'd say try setting the mains to small, then measuring and equalizing the response of the sub.
     
  9. Chris PC

    Chris PC Producer

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    I am going with the mains SMALL. I will measure the room response of the speakers alone LARGE and alone SMALL just to get an idea and then I'll measure the response of the subwoofer alone and then I'll measure the response of the fronts SMALL and the subwoofer and see what I get. Its just weird because there seems to be a strange phase problem. I have found the best sound comes from what I think is a weird position, so far anyways. I'll keep working on it [​IMG]
     
  10. Phil_O

    Phil_O Stunt Coordinator

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    I also have this sub and I have a their LFX-1 outboard crossover connected to it. It has a sub level dial, crossover high pass and low pass dials, and a phase switch you can set to 0 or 180. Most rooms should be set to the default(0), but maybe your room is different. I'm not a room or bass expert but maybe you could look into getting one of those so you can switch your settings better.
     
  11. Chris PC

    Chris PC Producer

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    I was looking for one of those crossovers to use in between my receiver and an amp, but haven't really found one. Thanks for the advice though. What main speakers are you running?
     
  12. Phil_O

    Phil_O Stunt Coordinator

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    Paradigm Monitor 5 v2's. They sound really good with the Mirage on music and movies. They really need a good sub to help them in the bass range though. The Mirage *can* get a little boomy with some placements but it is possible to eliminate that.
     
  13. Chris PC

    Chris PC Producer

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    Thanks for the feedback. So what placement was boomy for you and how'd you fix it?

    Anyone with a Mirage BPS-400 have pics of their subwoofer and speakers placement and/or there setup within their room? I'd love to see pics of someones system including a BPS-400. I have yet to see one in someones HT or Stereo.
     

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