Sold the CHT-10

Discussion in 'Speakers' started by Morgan_, Jan 15, 2005.

  1. Morgan_

    Morgan_ Stunt Coordinator

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    Yeah, Thursday I sold the Velodyne CHT-10 sub. Set it up for a 7 day auction, put a "buy it now" on there for $160 +40 shipping, and someone snagged it in 28min! It was new, like 6 months old, so somebody got a fairly good deal. I think I payed $210 for it on sale, free shipping. I'm happy. The way I look at it, now my new SVS PB10 coming on Monday is costing me $310. Sweet. Now, I needed a new project cause I'm bored, so I'll be rebuilding the onkyo sub I have in the computer room. I'm changing the amp to a 250w rms, and changing the driver to a peerless cc subwoofer, beefing up/dampening the cabinet. It's got a 4" tuned port, woofer bottom fires, and it's got a real nice low note when you thump the woofer. It'll be fun to see it crank and shake the walls and floor! Stock, it was listed as having 150w "dynamic" power amp, so I figure it has a 60w rms amp, and had a listed response of 180hz to 27hz, but testing it, you could barely hear a whisper of 31.5hz, really the usable low limit on it was 40hz or so, I'm going to get it down to 20hz, at maybe 88-90db at that freq, I'm going to try, it's gonna be fun to get it to outperform the CHT-10. Onkyo sub below.
    [​IMG]
     
  2. RobLJ

    RobLJ Stunt Coordinator

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    Please keep a detailed log. I'd love to do the same to mine. [​IMG]
     
  3. Mike^S

    Mike^S Stunt Coordinator

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    20hz?? Have you done this before? It doesn't seem possible to get 20hz out of a cabinet like that.
     
  4. Morgan_

    Morgan_ Stunt Coordinator

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    I'll be getting my order from parts express Thurs, and work on it next weekend, then I'll do testing and post an update.
    The new driver is rated to go down to 25Hz, and at 20Hz, it's only 10db less output than it is at it's highest output, it's fairly flat. The amp I'm using is pretty neat, it's got a soft clip feature to provide low distortion all the way to full RMS rating, and to eliminate distortion, so they say I won't be able to distort it and be able to really crank it. Also, the amp has a filter that starts to kick in at 20Hz and lower, and at 18Hz, it drops -3db, then I imagine it drops rapidly to prevent driver over-excursion, rated at 12db/octave. It'll be fun testing it when I'm done. If it goes to a usable 25Hz at good volume, I'll be really pleased. If it goes audible 20Hz, I'll pop wood[​IMG]
     
  5. RobLJ

    RobLJ Stunt Coordinator

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    [​IMG] Like I said...keep us posted. I'd like to 'tune' mine up too.
     
  6. Geoff L

    Geoff L Screenwriter

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    Dose not matter how good a driver and amp you use, if the sub is ported, (it's tuned to a certain freq by the port size & length for it's cabinet internal volume).

    You must change the length of the port, (longer) to lower the tuning (to get lower response) in the same cabinet. Also a driver is needed that will work in that size cabinet volume, and the tuning that it has/or will have if you change port length.

    You maybe aware of all this and just did not include that in your post, deeper tuning change..

    Or maybe your changing it and (going sealed)...


    I apoligize if I read your posting wrong...
     
  7. Morgan_

    Morgan_ Stunt Coordinator

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    Yeah Geoff, I'm all over it! I love these calculators for lazy speaker fiddlers like myself![​IMG]
    Here's a few, lot's of them at this site, box calc:
    http://www.carstereo.com/help/Articles.cfm?id=45
    Port calc: http://www.carstereo.com/help/Articles.cfm?id=31

    I can even figure out what length the port tube in the SVS PB10 that I'm getting delivered from ups tomorrow (yes!) Well, that is if they tuned it for 20hz: 3" port, 2.7-2.8cu ft, somewhere around 15" length, if, I say if, they wanted it tuned at 20hz. That cabinet is 21.5" deep, so I'd say there was 20" internal volume to stick any long port depending on where they wanted the boost at.
     
  8. Geoff L

    Geoff L Screenwriter

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    Morgan

    What exact Peerless driver are you panning to use, what Amp, and what diameter port and ow many, and is it/they a flared PP port???

    Could/might you be kind enough to post either part numbers for them from their web site purchased, or their model numbers.
    I assume everything is coming from PE like you aluded to...

    I understand playing/rebuilding, it can be very fun.

    Tanks
    Geoff ¥
     
  9. Morgan_

    Morgan_ Stunt Coordinator

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    ONKYO SUB RELOADED
    Enclosure volume: 1.4
    Port diameter: 3"
    Port: Flaired at both ends, from 3" to 5", 11.5" long, tuning freq: 31.5hz
    Peerless CC Subwoofer, Xmax: 5.5mm, Fs: 25hz, 150w/rms
    Amp: 240w rms/4ohm, 170w rms/8ohm
     
  10. Morgan_

    Morgan_ Stunt Coordinator

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    [​IMG]
     

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