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bgavin, MickeyD---subs

Discussion in 'Amps and Cabs [BG]' started by ThunderStik, Sep 13, 2001.


  1. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    http://www.cerwinvega.com/products/index.html

    I hope I got the link right . This looks pretty good what do you guys think? It look like its got a built in high pass filter so you can run a 2-10 or something on top of it without the use of an external crossover, that would be nice. I emailed them to get the +/- db rating , they show 32-150 but at +/- what. This looks really good to me but I need more eyes on it to "shoot it down" so to speak. whatcha think? Its the mi series sub 15.
     
  2. My first thought is for you to audition it in person with your rig. I suspect if you buy it unheard, you will be disappointed.

    The 101 SPL sensitivity tells me the 32 Hz rating is probably at -10 dB. It will be interesting to see if Cerwin-Vega will commit... but I don't think you will get an answer. You cannot get loud, low, and small in one box... laws of physics won't support it. See this site for a nice explanation:

    http://www.trueaudio.com/st_trade.htm

    The 6 dB slope on the low and high pass filter is nothing more than an inductor and capacitor, respectively. Not much of a crossover slope, but I suspect this woofer is probably nothing above 150 Hz anyway and it will work just fine.

    Pure advertising bullsh*t is my opinion. We've been down this ugly road in other threads before. One port or multiple ports... all they do is tune the box to a given frequency. If C-V would offer a response chart, etc, it might be more credible. It is easy to lie when you don't have to substantiate your claims.

    Audition it with your own ears and rig, then decide.
     
  3. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Thats the bgavin I know and love.:D
    Thats what I was thinking ( the box is very small). While we are on the subject I need to learn more about crossovers and you look like the guy. When they say "slope" what are they referring to? When a xover is a 4ohm does that mean it introduces a 4ohm load into the chain or the load on the other side of it cant be less than 4 ohms.
     
  4. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    anybody?
     
  5. Slope is the rate of rolloff measured in dB per octave at the crossover point. The crossover is often designed where each driver is down -3 dB at the crossover point. The sum of both driver outputs brings the combined signal level back to flat.

    A crossover with a gentle slope does not offer as much protection to the driver as does a higher slope. This is important to tweeters as they can be easily blown out by low frequencies.

    http://www.trueaudio.com/st_mr1.htm

    The above link is part 1 of 2 in a well written article. Be sure to read the 2nd part also... lots of good info, but dated to 1980.

    http://www.trueaudio.com/st_lrxo1.htm

    The same author also has a paper on the 24 dB slope Linkwitz-Riley types which have taken over the active crossover market.

    A passive crossover only operates correctly when the impedance of the drivers at the crossover point is correct with the design of the crossover network itself. An 8 ohm load will require different inductor and capacitor values than a 4 ohm load.

    The impedances of the two drivers controlled by the crossover are NOT a parallel load, but distinct from each other. You can custom build a crossover for an 8 ohm woofer and 16 ohm squawker by choosing the correct components. The impedance presented to your amp is frequency dependent and will be that of the driver that is operating at that frequency.

    Passive crossovers are very sensitive to incorrect impedance matching, plus other problems with different sensitivities between drivers. Active crossovers such as Rane avoid all this hassle and let the user control both the crossover point and the individual loudness of each driver. IMO, the only way to bi-amp..
     
  6. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Ask and yee shall receive, thanks . Very good reading , so what has changed in the last 20 years that I need to know about?