M-A3

Current system:

Car: 2006 Audi A3
Head Unit: Audi Navigation Plus RNS-E (configured for Bose mode, giving flat response via preamp level outputs)
Front Components: Focal 165 K2P UV (mid at bottom of door, tweet in bottom of A-pillar, stock locations) (using Focal's supplied passive crossovers)
Rear Fill: Stock Bose (faded almost out)
Sub: JL Audio 10w6v2 in custom .7 cuft custom built fiberglass enclosure in driver's side corner of trunk
Amp1: JL Audio 300/4 bridged delivering 150 watts * 2 to front components
Amp2: JL Audio 500/1 delivering 500 watts * 1 to sub
Amp3: factory Bose amp delivering a couple of watts for rear fill
Deadening (so far): Cascade VB-2 covering inner skins of front doors, Cascade DPP7 deflex pads behind front mids
Crossover points: sub HP 25 Hz at 24db/oct, sub LP 75 Hz at 24db/oct, front HP 65 Hz @ 24db/oct

Background: I went to "the Source" and picked up an SPL meter (Scosche SPL1000F, digital, C-weighted) to plot out my system's freq response as I felt some freqs were a bit lower volume than others. I tweaked my sub level and crossover points to make a nice transition between the sub and the front mids while keeping the sub LP as low as possible and still protecting my front mids from overexcursion at my preferred max volume level. After testing the lower octaves and getting a resulting response curve with +/-3 dB response, I thought I'd start testing from 200 Hz up.

Problem: checking the SPL at 1/3 octave intervals, I note a 13 dB dip at 500 Hz.

Questions: 1, could this be a "feature" of the Focal mid? 2, what might be able to be done to my interior to mitigate this dip? 3, should I look at adding an eq to the mix?

If an eq is the answer, please give me your thoughts on the AudioControl DQXS vs Rockford Fosgate 3SIXTY.2 or other small form-factor eq with remote adjustment capability.

Optional question: 4, the 300/4 is actually a 75 watt * 4 amp - any benefit to going true three-way active with the Focal component set to alleviate this issue, or would that just complicate things further? With the combination of the 500/1 and 300/4 I could do a bandpass and high pass setup for the mids and tweets.

Thanks in advance for your comments.

theif

Sounds like alittle phasing going on . I think your dip could probably be corrected with a little time alignment . I have the same components and did the same proceedure with an spl meter before and after TA and must say the focals produced a much flatter responce curve after time correction . It took barely any eqing " less than 2 db in 1/3 octave segments " to get it almost _________________ .But different cars, different problems and usually different solutions .Even if i,m not right i,m sure you,ll get the right answer soon since theres so many people on here who won,t post except to correct someone .

M-A3

If only I had gone the aftermarket route on the head unit. I see your DEH-P880PRS gives you all the tools to EQ and TA right there. My RNS-E gives none - even the treble and bass controls are kinda useless and I haven't seen anyone yet to hack the firmware and add additional functionality. However, the OEM look and functionality of the unit with Nav, bluetooth, SD cards for MP3s (when I don't care about SQ), etc. I just can't give up.

So it looks like the Rockford Fosgate 3SIXTY.2 might be my answer. Sexy unit, especially with the bluetooth remote control built in... however, I'm curious if anyone has heard the sound quality of this unit.

And why don't AudioControl come up with something with TA? I guess maybe more comp-level head units have it included these days... but they've already got the DSP, why not add a bit more functionality? Any AudioControl reps able to comment out there?

Anyone know of anything else comparable to the RF 3SIXTY.2?

SweetnLow91SC

nope, it is usually created by the interior dimension and the placement of the driver. unfortunately eq can't help too much sonically... but it could help visually on a rta. it usually sound worst when boost over 3db. in most case it is left alone unless you're competing or determine to fix the problem.

M-A3

Interestingly, tonight I was showing a friend the SPL levels of the sine sweep. He wanted to see if he could hear the dip.

When we got to the frequency in question, the dip was gone! But of course, the interior of the car had changed with his legs now occupying the passenger footwell. When he got out of the car, the dip returned.

Since I don't want to move the mid driver to a kick, I'm thinking time alignment to some degree may be the only answer.

I'm not competing, just looking for a reference sound reproduction to listen to good recordings in a good stereo space. I saved a bit of cash building the sub enclosure myself over many weekends, so I can afford one more device for the chain to make it as perfect as 2.1 sound can be with speakers in the stealthy stock locations.

Anyone tested the Alpine PXE-H650? Could this be another option?

JohnVroom

you could try swapping phases on one of the midbass drivers, that should do about the same thing as a TA adjustment... not as good but it should be effective certainly cheaper

Buzz

iTrader: (1)

Purchasing one as soon as it becomes available, supposed to be the end all be all for TA, among other things.