How do you Calibrate a Subwoofer?

Discussion in 'Speakers & Subwoofers' started by Kevin_T, Jul 14, 2004.

  1. Kevin_T

    Kevin_T Extra

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    I just got my Dayton 10'' subwoofer and I have no idea what I'm doing. I used to have a cheap sub with only the volume knob and one RCA input, but now there is a crossover knob, 0-180 degrees switch, volume, and all sorts of inputs and outputs. I got the sub working so I can hear it, but it's softer than my old 6.5" 50 watt sub. It almost sounds like the sub isnt even on in speaking parts of movies. The overall bass presence just isn't there. Can someone help me please???

    P.S. It's right out of the box, so everything is set on default
     
  2. ChrisWiggles

    ChrisWiggles Producer

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    How do you have it hooked up?

    I would recommend using a test disc and a Radio shack SPL meter to calibrate your subwoofer. If it's too soft, turn up the volume knob slightly, though calibration is the only way to get thigns right. This has been discussed thoroughly in the past, and I believe it is covered well in the Primer/FAQ.
     
  3. DavidNighorn

    DavidNighorn Stunt Coordinator

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    I just did this for the first time last weekend. The first thing to do is to work on sub placement. I had the sub in a rear corner with the ports facing the back wall about 7" away. Then I did a sweep test using the SPL meter. Ugh. I had very weak response below 20hz, and huge nulls at 30-40hz and 50-60hz.

    I then placed the sub in the same corner with the ports facing the corner itself. The sweep test showed an improvement in each of the nulls - but not enought to call 'smooth'.

    Then I turned the sub so that it was 7" from the side wall with the ports facing that wall. Now there was a huge improvement - but still not smooth. The 50hz range was still pretty weak.

    Finally, I started working on the phase control. My sub has a variable phase from 0-180. First I tried switching to 180 with negligible results on SPL. The nulls were still there. From this point, I started turning the knob in 25% increments starting back from zero. When I got to the halfway point, everything started to come back into line. There were no significant nulls! Finally, I ran the warble test tone to make sure that this didn't affect my speaker balance with the mains. No problems!

    The last step was to run the speaker level matching. Voila! Calibrated.

    My biggest piece of advice is to work on the sub placement. I moved my sub a grand total of 12" and changed its relationship to the surrounding walls - with great results.

    David
     
  4. Kevin_T

    Kevin_T Extra

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    I moved my sub into the back corner with huge results. This is what my room looks like. The sub used to be under the front right speaker. It's is an acoustical mess, I know. The open space is a rail overlooking the downstairs. Maybe a thick curtain would help when I watch movies.

    I dont have 15 posts so I cant post a URL, but just copy and paste the two together.

    uploadimages

    .net/images/807598Room2.JPG
     
  5. Kevin_T

    Kevin_T Extra

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    Is it normal to have a crossover frequency set at 115 Hz? I have it there right now and it seems to be fine. The main speakers are small and dont have much bass.
     
  6. Brad_See

    Brad_See Stunt Coordinator

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    I wouldn't think that you're really going to hear your sub much in the speaking parts of movies anyway unless the person speaking is Darth Vader or "the source."

    brad cook
     
  7. Kevin_T

    Kevin_T Extra

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    I know, but my main speakers produce so little bass that there is a noticable difference with the sub turned off. That is why I set the crossover so high. But I always thought the crossover should be between 60 and 80 Hz instead of 110 to 120 Hz.
     
  8. Brad_See

    Brad_See Stunt Coordinator

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    I have the crossover on my Dayton set at about 80 hz. It sounds great. Sounds like you need to invest in some new fronts next.

    brad cook
     
  9. Kevin_T

    Kevin_T Extra

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    ya, I know. [​IMG]
     
  10. Kevin_T

    Kevin_T Extra

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    Ok, OK, OK. After digging through all the manuels and specifications of my system, the satellite speakers I own have a frequency range of 160 Hz-20,000 Hz. Doesn't that mean that the crossover for the sub should be set to the max frequency ( which happens to be 160 Hz)?
     
  11. GregBe

    GregBe Second Unit

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    Kevin,

    You want to set your crossover at 160 Hz, if that is how low your mains extend to. If you go any lower, you will get a hole and not hear the information between whatever you set your crossover at and 160. Although this is a high setting, it isn't the end of the world. You should really try to keep the sub in the front of the room, because set that high, you might be able to locate what sounds are coming from the sub, and what sounds are coming from the main speakers. You might also want to listen for boominess. Sub placement is always critical, but set this high, it is crucial. Be patient and try different locations in the front of the room. You may not want to calibrate your sub too hot. Since your sub will be playing in the 160 Hz and higher region, it will play voices, which when set hot will sound out of sinc with your center channel.
     
  12. DavidNighorn

    DavidNighorn Stunt Coordinator

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    WRT to crossovers, what are you guys using for receivers/processors? Most of the time, the crossover is set at either the dvd player or the receiver - whichever is doing the sound decoding. When that is the case, you can generally set your sub crossover to maximum to ensure that it doesn't compete with the first crossover.

    As an example, if you have your receiver set so that all of your speakers are 'small', then you will probably get ann 80hz crossover point. Some more expensive receivers allow for individual crossovers to be set. But in our case, let's assume that the receiver sets the crossover to 80hz. That means that everything in your main channels below 80hz is sent to the sub. This is in addition to the LFE channel which goes directly to the sub. The crossover knob on your sub isn't going to buy you anything once its setting goes over 80hz. All you will do is limit the high end of the LFE material.

    The only time to use the sub crossover is if you are running your system with full-range speakers (large). Even then, I would probably set the crossover at the receiver instead.

    David
     
  13. GregBe

    GregBe Second Unit

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    David,




    It depends on his setup. If his receiver has a fixed crossover of 80, he most certainly should use speaker level inputs to set up his sub with those particular satellite speakers. Set mains to large, sub to off, and connect the sub through the mains. You can then use the crossover on the sub to have the sub play as high as you want. If you have receiver with a flexible crossover, certainly use the line level input, but if not, speaker level is the way to go with small sats.

    Greg
     
  14. DavidNighorn

    DavidNighorn Stunt Coordinator

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    Greg,

    Thanks for the additional info. It never occurred to me to use the speaker level inputs on the sub.

    David
     
  15. Kevin_T

    Kevin_T Extra

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    Im going to try the speaker level inputs on the sub. My reciever does not have a crossover knob, so the only thing I can use is the knob on the sub itself. I think this will do the trick because when I set it above 80Hz at the moment, I get an airy noise, but no real bass. So im thinking my reciever has an internal crossover of 80 Hz.

    The easiest thing to do would be get new mains, but for the moment this will have to do. [​IMG]
     
  16. GregBe

    GregBe Second Unit

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    Kevin,

    Don't feel pressure to upgrade you mains. You will get the itch soon enough. You have a nice sub. Set up your system right and enjoy it. If you don't have a crossover setting on your receiver, it is most certainly a fixed crossover. I think speaker level setup will do the trick for you.

    Greg
     
  17. Kevin_T

    Kevin_T Extra

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    It WORKS!! [​IMG] [​IMG] [​IMG] . The speaker level setup is exactly what I needed. I turned the sub off on the reciever and did everything you said. It's amazing. I can't believe I've been missing out on so much! I will play with placement later, I have a very open room and there is only one real corner right behind my couch. I played that shockwave scene from the Lord of the Rings : FOTR and stuff in my room shook!

    One more question, though. In an open room like mine, is it best to keep the sub as far as possible from the open space?
    My room has three walls and then just a railing overlooking the downstairs. Here are some pics of my setup:

    [​IMG]
    [​IMG]
    I want to put it back in the corner behind the recliner
    [​IMG]

    Don't be fooled though. The floorstanding speakers are broken and only serve as stands for my satellites.
     
  18. Brad_See

    Brad_See Stunt Coordinator

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    I was just about to ask.

    brad cook
     
  19. kyle ^_^

    kyle ^_^ Agent

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    My sub came the other day, and i used the speaker level inputs and have gotten good results. What sub setup did you have before the dayton?
     
  20. Kevin_T

    Kevin_T Extra

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    It was a 50W sony sub. It was an in-a-box sort of thing so I don't see the model number anywhere. It only had a mono RCA input and a volume knob. It's cut-off frequency was 150 Hz, while the speakers it came with had a low end of only 160 Hz. I don't really get why Sony put those two together. It seems like they just randomly chose speakers. The reciever is nice, however, I don't think I'll go with Sony speakers again.
     

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