Velodyne CHT-15 Questions

Discussion in 'Archived Threads 2001-2004' started by Randy Noel, Oct 9, 2002.

  1. Randy Noel

    Randy Noel Stunt Coordinator

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    I have a CHT-15 on the way, and don't know the first thing about how to set it up! I'm replacing an 8" BIC sub:b to complete my setup. I have 4 JBL S-36, S-Center, Tosh 65HX81, in a room approx. 12' x 15' x 7.5'. I probably only have two options for sub placement- either the front left corner of the room, about 3 feet from the front wall, or the back left corner behind the sofa, which sits about 2 1/2' from the back wall. I need some advice on placement, calibration, etc., or someplace to look for information intended for someone who doesn't understand the technical jargon, i.e. nulls, room gain, etc. I do have a rat shack SPL meter. Any help for a novice would be appreciated.
     
  2. Randy Noel

    Randy Noel Stunt Coordinator

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    BTW, I have a Sherwood Newcastle R-945 Receiver, if that makes a difference.
     
  3. steve nn

    steve nn Cinematographer

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    Hi Randy, I might be able to help some? I am fairly new to all this and am learning the basics myself. I do have two of the subs you speak of and I can tell you from your room dimensions you are not going to have any problem at all with lack of bass as long as you can place it in a decent spot. When you say front left corner 3ft from the wall are you saying kind of in the corner but 3ft out from the corner? What will you be calibrating with? How far is that corner from you?
     
  4. Randy Noel

    Randy Noel Stunt Coordinator

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    I'll use AVIA for calibration. Front location is about 3' from the front wall (wall where the RPTV is) and right next to the left side wall. This would place it about 8 or 9' from listening position. Back left corner would be right in the corner, about 4' from me, behind a sectional sofa.
     
  5. steve nn

    steve nn Cinematographer

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    IMO I think you would like the front option better. Close to the TV and still corner loaded. This sub will not be like your previous 8" sub. You will feel it and it will give you a much closer cense of being there. If you put it next to your couch you probably would suffer isolation and other possibilities. What % HT versus music will you be using it for?
     
  6. Randy Noel

    Randy Noel Stunt Coordinator

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    95%HT, 5% music
     
  7. steve nn

    steve nn Cinematographer

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    Same with me basically. I am close to a 100%. Since this is the case you might want to run it a little hot. I would go with +3db and see how you like that. Set your sub level gain on your receiver to the middle value or +1 and the gain on the back of your sub set at 3 1/4 to 3 1/2. This might be a good starting point to make final adjustments. I could be way off but probably fairly close. Speakers small-sub on-low L connection, the usual. On the back of your sub you will have two options, Audio/Video- I go with the Video. More output not quit the extension. Put x/over switch in the "in mode position" on back of sub to let your receiver do the x. How does this sound for a place to start?
     
  8. Michael Roderiques

    Michael Roderiques Stunt Coordinator

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    Randy A CHT-15 sub. Man you must want to feel the bass!.

    Seriously, the CHT15 is a great unit. I think for the money it is a hard to beat unit.
    There are some units out that will give it a good challenge, but overall, I think you will be very happy with your choice.

    On your set up of the unit.

    I would recommend that you try to place it up on the front wall. I think you will get the best overall performance from that location.

    Here is a sort of backwards trick you can use to help find the best location for your sub.

    Place the sub as close to the listening position as you can. Take a CD player, regular or portable and connect it to the line in on the sub. Set the sub volume on the 4th dot and play a bass heavy CD. Walk around the room. The place where you hear the best clean clear solid bass is a good starting point for locating your sub. It will need some tuning once you get it in place, but this will get you close to start.

    Install and calibration. I would recommend that you get an SPL meter. It will help you so much that you will be surprised at what your system will sound like after dialing it in with an SPL meter.

    On the interconnection cable. Use a single cable fro your receiver to the subs location, then a short “Y” adapter to both left and right INPUTS on the sub.

    Once you get the unit into the place you will use it, power and signal feed to the sub, you will need to go to your owners manual for your receiver or processor and follow the instructions for installing and setting up for use with a subwoofer. It is quite easy to do.

    On the CHT15 you should find the following controls.
    Knobs Volume and Phase.
    Switches. Power, audio/video and an crossover, it may say Xover or internal and direct.

    Set the volume control about 4th dot to start.
    Set the phase to “0”
    Set the switches to Power to “auto” the unit will turn on when you use your system
    Set the Audio/Video switch to “audio” Only use video if a movie has low bass output
    Set the Crossover to “out” or “direct” depends on what your markings are.

    The recommended procedure for setting up a Velodyne sub is to place the “volume” control to a starting point. Say the 4th dot. On most Velodynes the optimum working range is from the 3rd to 5th dot, you can go lower, but you don’t want to go higher.

    Have your source set to it’s mid point, most systems this is “0”

    With a test tone AND some form of other audio, take reading from an SPL meter.

    If the measured out put is significantly higher, adjust the SUB gain down ½ a dot and re-test. It is the other way, move the gain up ½ dot. Do this a ½ dot at a time until you get close.

    When you are close to the reference you are looking for, make the final adjustments with your processor output. Ideal would be to have no more than a working range of 0 to +2 on the source and 3 ½ to 4 on the sub. If this range is not cast in stone. It is the best starting point and for most the optimum working range. I have seen units down as low as 2 dots.

    To eliminate some problems with the auto on functions, try to never go into a negative number on the source, if you have to think about going this way, bring the sub down first. Try not to have the subs “volume” below 1 ½ dots.
     
  9. steve nn

    steve nn Cinematographer

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    Yes the Y. This really helps. I was going to mention. You know Michael I think I will try calibrating in the audio mode and see what that has to offer. Could you give me your thoughts on the audio versus video mode?
     
  10. Michael Roderiques

    Michael Roderiques Stunt Coordinator

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    Steve

    The Video mode on the CT-150 and CHT -15 give the unit about a 6db boost in output.
    This is used for older sound tracks that may have the theater mix. In a lot of theatres the bass is mixed in lower than the mains due to the centre and mains are usually behind the screen or curtains, while the woofers and subs are usually not. So to compensate for the theater, the bass frequencies are cut an average of 6bd.

    On a CT/CHT system, it is best to use them set in Audio mode unless you need the boost. They will actually sound better in audio mode.
     
  11. Randy Noel

    Randy Noel Stunt Coordinator

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    Thanks for all the help. BTW I do have the SPL meter already, so I will use it for the calibration. Thanks again![​IMG]
     
  12. steve nn

    steve nn Cinematographer

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    I definitely know I get a boost from using the video mode. With using two, I think I should try the audio. This will give it a little more extension and run a little flatter I think? Worth a try. Take note Randy. You might try the video mode and see what this sub can do and then go to audio mode and recalibrate. I will try it in the next day or so and give you my take on it. I think the audio mode will help tame. Maybe to much for me. Other Velo user's like what video has to offer for HT and I always like things set at there optimum. Sheer power or smoothed out a bit. Worth a try. Randy when are you due for your Velo? I took your advice Michael and calibrated each sub individually. It worked out great. +6db [​IMG]
     
  13. Randy Noel

    Randy Noel Stunt Coordinator

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    Should be here next week sometime. Think the wife will notice[​IMG]
     
  14. steve nn

    steve nn Cinematographer

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    I am afraid she will. I think I here a word or two five out of seven days a week. If not for shaking the house then for taking up a precious corner. I was shaking things off the bathroom shelf the other day and did not even know it. I kept wandering whats going on in here-whats the deal with this shelf? She was in there the other day when things began to fall. Now I know! Its all good and worth it though. I did recalibrate in the audio mode and I will get back when I have more time. I will say I did have 105 db peaks watching the pod race at -5 and at -13 I was at 98-100 db peaks quit often. This was at a +2db calibration on the sub. Its one thing to upgrade from a good sub to a better sub but it will be incredible for you going from your BIC 8" to the Velo 15". [​IMG]
     
  15. Randy Noel

    Randy Noel Stunt Coordinator

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    Maybe I'll go around the house and attach velcro to everything on shelves before I crank it up![​IMG] I'll let you know how it goes!
     
  16. James Bergeron

    James Bergeron Supporting Actor

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    I use the audio mode, I was using Video for the longest time because that is how I calibrated it and when I switched to Audio I felt it to be weak. But I tried calibrating it on Audio and I like the difference it seems more clean and deep. I think video is more like a 30-40hz hump or something. That is what it seems like anyways.

    As far as the Y adapter, I see everyone saying it makes a difference but if you calibrate it properly, I have tried with and without and there is no difference. I may make a difference if your receiver puts out a lower voltage on the .1 channel. I'm using a Denon 4800 and it makes no difference for me.
     
  17. Randy Noel

    Randy Noel Stunt Coordinator

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    If it's possible to place the sub in the back left corner behind the sofa, it would work out best from an aesthetic perspective. If I do this, and the sound is degraded, are there steps I can take to compensate? Would a sub EQ help here?
     
  18. Randy Noel

    Randy Noel Stunt Coordinator

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    double post, sorry
     
  19. steve nn

    steve nn Cinematographer

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    AHH! Its Fri and I am home. What a week[​IMG] . It can work Randy but it is going to be pretty close though. I tried parting mine and it worked out with one close but that was with two. Some find favor with this setup so give it a try. It will just eat at you if you don't. James good to see you chime in. The Y really does help me but I am not running a Denon 4800 either. I wish I was! Maybe I just need all the help I can get? Seems like I have seen you wade in before on the Y topic. I guess you won't be doing any more in house comparing or will you? I put a post in on your old thread comparing the VTF-3 to the CHT-15 hoping to get a stir from you and see if you had laid to rest any other plans? I have to turn the gain up 3/4 of a notch on the sub and +2 more on the receiver to get +2db calibration in the audio mode. Smooth, powerful, clean and not a trace of boomyness. I was thinking the same on the hump. Randy I have no experience with EQ so I can't be of any help. From what I here though EQ can always benefit. It will depend on the room and the sub how much you benefit, I think?
     

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