How to adjust my input sensitivity

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How to adjust my input sensitivity

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I have a Kenwood KAC-7204 amplifier that I just bought a new sub for. The amp is rated at 170w rms at 4 ohms per channel or 500w rms at 4 ohms bridged. I plan on bridging it for my 1300w peak, 300w rms Kenwood eXcelon KFC-XW100. I don't want to over power the sub since its only 300w, is there a way to adjust the amp setting to run the sub to its max without harming it? Thanks!

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  • You can use a multi meter and ohm's law. 300 watts x 4 ohms = 1200. sq rt of 1200 = ~34-35 volts AC

    GLH Geeked

  • The DMM method is a conservative way of setting gains. You'll play a sine wave test tone of 50Hz or when measuring the output of the amplifier.

    Anyways, first thing you need to do is find your HU's maximum clean output level and then use that when setting gains.

    A DMM is not very useful in detecting distortion/clipping, so you'll pretty much be at the mercy of your ears and test tone (unless you know someone with a DD1 or O-Scope). this isn't as bad as it my sound, as distortion is fairly easy to hear when playing test tones.

    I know it talks about setting amplifier gain by ear as well, but what I want you to focus on is finding the HU's maximum clean output level using the same method. A good read overall, but it doesn't really take about using test tones to find the HU's maximum clean level until the bottom of the article.

    It is often recommended to use a 0dB reference level test tone, which will help to insure clipping/distortion are minimum to nonexistent. However, it often results in lackluster performance. If when you set the gain with a 0dB 50Hz test tone the performance is lack luster, re-set the gain using a -3dB 50Hz. If again it's underwhelming, use a -5dB test tone. I'd not use anything more attenuated than that personally though.

    You can download test tones from all over, but I recommend making your own with Audacity (it's free to download and use)