Head unit distortion

[/////lpine 85]

Does anyone know when the internal amp distorts on an Alpine CDA 9886? Also the pre out for the subwoofer as well? Thanks.

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[1aespinoza Premium Member]

Does anyone know when the internal amp distorts on an Alpine CDA 9886? Also the pre out for the subwoofer as well? Thanks.

Most common setting is at 75% of the radio volume. Some guys have used an oscilliscope to find the distortion level on the pre-out, and find that their radio can do 100% volume with no distortion.

 

[/////lpine 85]

Thanks. Did the 1k test tone at 0DB 23 to 24 is a small change in pitch. Once at 25 it's a very noticeable change on internal head unit amp. On loud recordings I find 24 to be around max. While lower ones 26 to 27 is max before I hear a little distortion in mids and highs. Ordered the Alpine S series 12 inch sub to match my s series 6.5 coxials. Used a 50hz 0 db for setting my sub amp gains. Gain landed right between a quarter and a the nom setting. 34.7 volts which is very close to the 34.64 target.

 

[ThxOne Premium Member]

Alpine says the Maximum Pre-Out voltage is 4v. You can test this in a primitive way with a VERY cheap harbor freight red multimeter. Set EVERYTHING flat in the head unit, EQ's, bass boost, loudness off. Send that 1Khz 0db tone through the head unit and with a multimeter test the RCA out's of the head unit turning up the volume until the meter reads 4V. Look at the volume level your head unit is at. That's your max undistorted volume. To be safe, back it off one click. Do the same for your Sub out as well but use a 40hz tone. If the volume is lower than the other RCA's then use the lower volume number. If it is higher, use the lower volume number.

 

[/////lpine 85]

Oh ok. So don't use a 50hz for the sub?

 

[ThxOne Premium Member]

Oh ok. So don't use a 50hz for the sub?

You can. 40hz is common as well. You're fine with 50hz depending on your crossover and crossover slope. If you are crossed over at like 80hz make sure your slope is steep like 24db or 48db until after you set the gain on the subs or cross the subs over even higher, set the gains and then back the crossover back down.

 

[/////lpine 85]

Thanks. I crossover everything at 80hz but, for my sub amp when setting gains I turn the crossover to max until I set the gain then back it to 80hz.

 

[ThxOne Premium Member]

Thanks. I crossover everything at 80hz but, for my sub amp when setting gains I turn the crossover to max until I set the gain then back it to 80hz.

Perfect

 

[audiobaun 5,000+ posts]

Nice!! This Thread should be a Sticky