Subwoofer Crossover Question

Discussion in 'Archived Threads 2001-2004' started by Kevin Knebel, Mar 3, 2003.

  1. Kevin Knebel

    Kevin Knebel Extra

    Joined:
    Jan 15, 2003
    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    0
    I'm wondering what the best sub crossover is for my set-up in HT. My receiver has crossover settings for 20, 40, 60, 80, 100, and 120hz. The front speakers are towers with 8 inch woofers. There rated down to 40hz. The center speaker is rated down to 60hz. I was thinking of setting the front speakers to small for home theater. Is it recommender to set your front speakers to large for HT? How much of a difference in sound is there when setting the crossover at 60hz compared to 100hz? Let me know how you handled this in your set-up's.

    I have the following set-up:
    Athena AS-F1's for fronts;
    Athena AS-B1's for rears;
    Athena AS-C1 center;
    Def Tech Pro Sub 100TL;
    Onkyo TX-SR800 receiver.
    Room size: 18x12x8
     
  2. JamieS

    JamieS Stunt Coordinator

    Joined:
    Feb 17, 2003
    Messages:
    222
    Likes Received:
    0
    Trophy Points:
    0
    It is really hard to reccomend a crossover frequency unless someone has the exact same setup as you.

    Here is my 2 cents.
    1. Unless you have some speakers with built in subs I think setting speakers to small works best. If you set it to large bass frequencies your spekers cannot do but the sub can get sent to your speakers. Not good for movies. Also you lighten the load on the Amp becuase the AMP on the sub does the work on the low bass leaving the reciever less work to do.

    2. What you really need is a Sound meter and a test disk to do a pink noise sound sweep this will help you pick the right crossover.

    3. I dont know the Def tech sub but if it has it's own crossover dial be carful of cascading crossovers.

    I have my Denon 1603 crossover set at 80 HZ and the sub crossover set to 100 HZ. I have all speakers set to small Monitor 7 CC370 and my PW 2200 sub seems to integrate well. Your setup could be toatlly different. I don't notice a huge differnce between a 80 and 100hz crossover on the reciever sond wise but the "standard" for movies is 80 so I left it there. When my test DVD shows up I'll work on the setup more.
     
  3. Kevin Knebel

    Kevin Knebel Extra

    Joined:
    Jan 15, 2003
    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    0
    What test DVD are you going to use?
     
  4. Brian Fellmeth

    Brian Fellmeth Supporting Actor

    Joined:
    Jul 30, 2000
    Messages:
    789
    Likes Received:
    0
    Trophy Points:
    0
    I second Jamies remarks. The short answer is that 60 or 80 are your best options.
     
  5. StephenL

    StephenL Second Unit

    Joined:
    Nov 21, 2000
    Messages:
    341
    Likes Received:
    0
    Trophy Points:
    0
    Crossover Setting and Speaker Bass Limits

    Unless your speakers are truly full range, with bass extension comparable to your subwoofer's, it is best to use the "small" speaker setting on your receiver or processor. It is important to match the crossover and speakers to achieve flat frequency response. If you use the crossover in your receiver or processor, then your subwoofer's crossover should be bypassed. If this is not possible, then adjust the subwoofer's crossover to the highest frequency.

    If your receiver or processor has an adjustable crossover it should be set according to the bass limits of your speakers. Note that many speaker manufacturer's specs are optimistic. Outlaw Audio's ICBM manual, page 13, has a table with typical crossover settings for common speaker types.

    Large tower speaker with one 12- or 15-inch woofer, or two 10-inch woofers: Bypass or 40 Hz
    Small tower speaker with one 10-inch woofer or two 8-inch woofers: 40 Hz
    Small tower or large bookshelf speaker with one 8-inch woofer or two 6-inch woofers: 60 Hz
    Bookshelf speaker with one 6-inch woofer or two 5-inch woofers: 80 Hz
    Bookshelf speaker with one 5-inch woofer or two 4-inch woofers: 100 Hz
    Satellite speaker with one 4-inch woofer or one or two 3.5-inch woofers: 120 Hz

    http://www.outlawaudio.com//products/icbm_manual.html

    Subwoofer Trim Level: Avoiding Distortion

    Using worst-case test signals, Sound & Vision magazine has measured high distortion at the subwoofer output on some receivers with the subwoofer trim level set to 0 dB. For such receivers, Sound & Vision now specifies the subwoofer trim level necessary to avoid distortion. So, depending on your receiver, you may have to set the subwoofer level below 0 dB to avoid distortion. I wouldn't exceed 0 dB in any case. You can adjust the subwoofer's amplifier level instead of the receiver's subwoofer trim level to obtain the proper sound pressure level when calibrating your system.

    For more information about bass management, see page 3 in Sound & Vision magazine's article "Behind the Numbers: Digital Sound Receivers"
    http://www.soundandvisionmag.com/art...&page_number=1
     
  6. BrianWoerndle

    BrianWoerndle Supporting Actor

    Joined:
    Feb 19, 2002
    Messages:
    794
    Likes Received:
    0
    Trophy Points:
    0
    It also depends on your room. All my speakers are good down to the mid to high 50s, so I tried using a 60hz crossover on my Denon 3803. The speakers handled it fine, but I think I hit a room node, becuase it sounded horrible. The bass was lose and hit and miss. So, back to 80hz for my room.

    Experiment. See what sounds better to you.
     
  7. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
    A few things are missing from this picture – namely, the slope of the crossover (“shallower” slopes require higher crossover frequencies), the size of the room (the larger the room, typically the higher the volume settings), and personal preferences on how loud the system is turned up.

    I really don’t put much stock in Outlaw’s recommendations. They are probably fine for music, but not for movies.

    For instance, I have mains with 8” woofs and 10” radiators that are easily good down to 30Hz or so. They perform fine full-range with music, even at relatively high volumes. However, when I crossed them over at 60Hz I had trouble with bass-intense movies overdriving them – and this was with steep 24dB/octave slopes. I had to move the crossover point up to 90Hz to keep from blowing out the 8’s.

    If you have a sub it’s generally best to cross over between 80-100 Hz, for a couple of reasons.

    First, when you get too many sources simultaneously generating low frequencies, you get a lot of phase (delay) problems. This gives poor response, and it also will make the bass sound “smeared” as the multiple low freq signals arrive to your listening position at different times.

    Second, any sub sounds better when it’s equalized, and you can’t effectively equalize if the mains are carrying a lot of the bass information – unless you want to try to equalize each main and the sub independently – a nightmarish prospect.

    Regards,
    Wayne A. Pflughaupt
     
  8. Edward J M

    Edward J M Cinematographer

    Joined:
    Sep 22, 2002
    Messages:
    2,031
    Likes Received:
    0
    Trophy Points:
    0
    I'm with Wayne 100%. Most low pass filter rates are 24 dB/octave, but some high pass filter rates are 12 dB/octave in order to smooth the transition to the sub, and this worsens the situation he described.

    Many DVD's have a full range, full power signal into all channels. If you run all your speakers on large and they cannot do full justice to the bass in that channel - you're missing it - it's gone.

    For a vigorous HT environment, a filter point of 80 Hz works very well even if you have large mains/center/surrounds. The real benefit of large mains/center/surrounds is their ability to fill a room with life-like presence and a huge, effortless soundstage. They will only struggle when asked to produce bass better suited for a dedicated subwoofer.

    Regards,

    Ed
     
  9. Derrik Draven

    Derrik Draven Supporting Actor

    Joined:
    Dec 7, 1998
    Messages:
    935
    Likes Received:
    1
    Trophy Points:
    0
    Real Name:
    Chris
    I have BP3000tl's for my mains and the 2000tl's for my surrounds. I set them to small, crossover set to 40, because using the avia disc and a spl meter, the monstrous (18"sub, 1000watt) 3000's, just start to labor in the mid 20hz range.

    When I test the SVS16-46, the db meter is absolutely pegged when it hits the dropoff point at 20hz.

    I'd be missing out on some bass if I did the mains/surrounds as large. Granted, they're in the ballpark but, they just can't beat the SVS.

    Still, I'm not cranking up the crossover to 80. Seems silly on my system since the mains/rears can handle 40hz without even breaking a sweat. Why send all the extra info for my sub to handle, between 40-80hz, when I can spare my sub for only the stuff below 40?

    Seems like accuracy, overall, would go up with the sub handling only what it really needs to.

    On the other end of the coin; say someone with a bass module and those teeny-tiny little cube speakers, with the crossover set to 120hz, would have alot of inaccuracy in the sub since it's literally doing damn near everything on top of "sub duty".

    Just my opinion. Set the crossover as low as your speakers can handle well, without getting too close to their dropoff point, as far as their performance is concerned.

    If your speakers are starting to have a real hard time at 40hz, but CAN make 40hz, don't set your crossover there since you'll really start to hear a dropoff and then, WHAM...your sub kicks in at 39hz and there is a big jump in bass.
     
  10. ChrisClearman

    ChrisClearman Second Unit

    Joined:
    Feb 5, 2003
    Messages:
    298
    Likes Received:
    0
    Trophy Points:
    0
    As a ballpark you want to set the sub crossover ~to where your main speakers cut out (based on your Reciever equalization and speakers). You want it to do everything from ~25 Hz (or whatever your sub can go down to) up to whatever your mains are actually putting out.

    Then fine tune w/ a setup disk.
     
  11. Zack_R

    Zack_R Stunt Coordinator

    Joined:
    Nov 4, 2002
    Messages:
    220
    Likes Received:
    0
    Trophy Points:
    0
    I have mine set at 60hz (for now[​IMG]). I have 40-200 (SOny 4ES) and think I've settled on 60. My mains have 15 inch woofs in them and when I take the crossover to 80 it makes the midrange sound a little thin for my taste.

    The one thing I wanted to make sure was is that if I was to crossover less than 80 than the sub would be going strong at 35 and below. According to the ratshack there is no detectable difference in output at 25 hz wih the crossover at 60. However, a crossover at 50 produces a valey in the 50-65 range.

    As a way to test, I would recommend turning your sub off and play just your mains while listening to music. Experiment with the different crossovers to see what makes them sound best. In my case when comparing large to the different crossover settings, 60 hz produced the best comibination of clarity and bass. Albeit less bass than if set lower or to large. Then turn on your sub and gradually increase the sube volume to where it seems to fill in and blend with your mains.

    Once you do that then run some test tones to make sure you don't have any phase induced cancellations or peaks around the crossover setting and adsjust as necessary.
     
  12. Willem Vos

    Willem Vos Stunt Coordinator

    Joined:
    Nov 14, 2000
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
    I have now set my crossover at 100Hz, because setting it to 80Hz gives me a -13dB dip around 85Hz.
    The fronts without the sub extend to 70Hz easily.

    It seems different crossovers settings cause different phase problems.
    Anybody know why this is?
     
  13. Edward J M

    Edward J M Cinematographer

    Joined:
    Sep 22, 2002
    Messages:
    2,031
    Likes Received:
    0
    Trophy Points:
    0
     
  14. Willem Vos

    Willem Vos Stunt Coordinator

    Joined:
    Nov 14, 2000
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
    Nope, no double filtering is set.
    The crossover on the sub is disabled, and I am just using the crossover on the denon (was using 80hz, now 100hz).
    The sub is connected to the sub pre-out.
     
  15. Edward J M

    Edward J M Cinematographer

    Joined:
    Sep 22, 2002
    Messages:
    2,031
    Likes Received:
    0
    Trophy Points:
    0
    Willem:

    Did you try reversing the phase at the 80 Hz filter point before abandoning it for 100 Hz?

    I had a very similar problem (8 dB drop at 79 Hz) and a phase reversal cleared it up completely, and also filled in the curve slightly from 80-60 Hz as an added benefit.

    Ed
     
  16. Willem Vos

    Willem Vos Stunt Coordinator

    Joined:
    Nov 14, 2000
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
    Edward: yes, I tried reversing the phase to 180degrees, but after doing that I got a dip at 70Hz instead of at 85Hz (so below the 80Hz crossover-point instead of above it)
    Changing the phase didn't solve the problem, just moved it elsewhere [​IMG]

    Setting the crossover to 100Hz solved this, but I'd really like to know why...
     
  17. Willem Vos

    Willem Vos Stunt Coordinator

    Joined:
    Nov 14, 2000
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
    bump
     
  18. Edward J M

    Edward J M Cinematographer

    Joined:
    Sep 22, 2002
    Messages:
    2,031
    Likes Received:
    0
    Trophy Points:
    0
    Well, if you are not cascading filters, and you have tried the different phase settings, at this point I can only suggest trying your FR sweep at a few different locations in the room.

    There might be a null in the room at that frequency at the key listening position - I've seen it before. I set up a system once where there was a 22 dB (!!) null at 56 Hz exactly at the best seat. Moving the mic two feet laterally in either direction lessened it to 13 dB - still not good but just goes to show you how bizarre room acoustics can be.

    If you do find there is a null being created, try experimenting with sub placement - to the extent that is possible.

    Ed
     
  19. Willem Vos

    Willem Vos Stunt Coordinator

    Joined:
    Nov 14, 2000
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
     
  20. Edward J M

    Edward J M Cinematographer

    Joined:
    Sep 22, 2002
    Messages:
    2,031
    Likes Received:
    0
    Trophy Points:
    0
     

Share This Page