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C-DSP with REW 5 years 4 months ago #37885

  • ctmeans0614
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Ok, total newbie questions. I have looked through lots of articles and how to's, but nothing for car audio, so I want to make sure I'm going the right direction.

Setup: Pioneer HU to C-DSP with Left, Right, and Sub inputs. I'm running active crossover to front stage (Mids are Rockford Fosgate PPS4-6, Tweets are JL C5-075ct). Haven't installed or set up a rear stage yet, and may not need to. Sub is a Rockford Fosgate P3 Dual Subs at 1 ohm. Running Rockford Fosgate Power series amps (mono and 4 channel).

Initially using the C-DSP for active crossovers with the following values:
Sub: High Pass Filter 27Hz, Low Pass Filter 170Hz, both using a 24db/oct crossover
Mid: Hight Pass Filter 170 Hz, Low Pass Filter 4000 Hz, both using a 24db/oct crossover

I set gains using a oscilloscope at each connection, and matched the clipping light indicator on the amps.

Sound is OK, and I'm sure I could tweek the crossover points, or the roll off curves for hand-off, but I wanted to see about further tuning with REW. I have a UMIK-1 and have it's calibration file and have installed REW software. Now questions :)

I have taken an initial measurement with a full range to test everything out. I did the step by step method in the article found here. My car's floor reading was 54db and with pink noise it was 95db and looked like it took a good reading (again, just testing and did not remove the crossover filters).

1. To take a measurement I take it I'm supposed to remove the C-DSP crossover filters (HU is all flat, except that the Sub channel forces you to use a high pass filter and I chose the lowest filter cut off at 50 Hz and there's no way around this I can see). Do I need to make the frequency sweeps that the speaker can handle and not a full spectrum sweep? (e.g. sweep sub from say 10Hz to 300 Hz). I would also assume this is much more important for the tweeters to start at 4000Hz on up to protect them, even though they came with capacitor in line to protect).

2. Do I measure each speaker individually, individually + Sub, and then full range with left side (tweet, mid, sub) and then rig ht side (tweet, mid, sub), and then all speakers including sub? I'm assuming all the different measurements are to give a picture of the range and how integrated all the speakers are, but as for tuning, it is done on an individual basis. Once this is done a text file can be imported into the C-DSP in the EQ section.

3. Once the EQ section is finalized, do you then turn back on the crossover set initially?

Any advice or articles to read would be greatly appreciated. Very willing to learn. I can post graphs as needed. Thanks in advance

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