DIY Time Alignment.

[clipto333]

hi,

i wanted to know if there are any circuits by which i can time align my front 2 way component speaker with the sub? the sub doesn't integrate well with the front stage.

please help me out with this as i don't have enough $$$ to buy a HU with TA. i was planning to get the alpine 9887 but i wont be getting it for another 2 months. im desperate to do this.

[jol50]

You could try to find a sub amp or a crossover with variable phase on it to use. Did you try running the sub out of phase?

[Dan2]

is the sub box ported?? when i had a ported enclosure the integration was also bad - but now that a have a sealed box it sounds much better.

[ppia600]

Just mount your subs in the front doors! (just kidding , although I have seen 12's installed in front kick panels with a lot of modification )

[jol50]

I want to put 8s in doors but my kicks are tiny....huge problem what to do with mid/tweets, and no dash places to put in. I think it would sound sweet though.

[clipto333]

Originally posted by clipto333
hi,

i wanted to know if there are any circuits by which i can time align my front 2 way component speaker with the sub? the sub doesn't integrate well with the front stage.

please help me out with this as i don't have enough $$$ to buy a HU with TA. i was planning to get the alpine 9887 but i wont be getting it for another 2 months. im desperate to do this.

Originally posted by jol50
You could try to find a sub amp or a crossover with variable phase on it to use. Did you try running the sub out of phase?

i

i have tried everything i can with my current setup. i have a pio deh-p 6850 mp3 HU. the fronts are Hertz energy esk 165, the sub is Hertz energy es380 powered by a pioneer gm-x944 amplifier. i have flipped the phase, i checked the phase of every speaker. its all in phase electrically.

Originally posted by Dan2
is the sub box ported?? when i had a ported enclosure the integration was also bad - but now that a have a sealed box it sounds much better.

i have tried both the enclosures. IMO only TA can improve the integration. let me know if there is a way without changing the HU.

Originally posted by ppia600
Just mount your subs in the front doors! (just kidding , although I have seen 12's installed in front kick panels with a lot of modification )

i have a single 15" sub which wont fit. lol. and i need to buy another for a stereo front stage.

[Eva]

And haven't you noticed the tremendous misalignment between the left and right channels? One is 50cm to 100cm far from you than the other!!

Aligning a sub is easily because front high-pass filters and sub low-pass filters can be tuned for phase matching in the listening position, despite the 1.5m to 2.5m distance error to the sub. Aligning the front stereo channels is not that easier.

[clipto333]

is there any ic or circuit i can use to delay a signal?

if possible, can anyone post schematics with pcb layout in eagle?

thanks in advance. im really lookin forward to it. please don't disappoint guys my only hope is this forum.

clipto

[Eva]

In the analog domain you can try "all-pass filters" but each stage is limited to only 90 degrees of linear delay at the highest frequency desired, thus a lot of stages are required to get something like 0.7ms up to 20Khz (0.7ms is the average left-to-right channel error for European cars). These analog filters are best suited to delay only a (sub)woofer or a midrange within its (crossover limited) frequency range.

You can also find out about "bucket brigade" delay ICs, but they are not exactly hi-fi. They are mostly used in low cost reverb circuits in musical instruments.

The third option involves converting the signal to the digital domain, storing it to RAM and then retrieving it and converting it back to analog in real time with a fixed delay. This is the DSP approach. There are low-cost ready-made solutions with lots of useful features, like Behringer DCX2496, that may be modified for car audio usage.

BTW: Some Alpine headunits include adjustable delays, parametric EQ and crossover too, but an entry-level pro-audio DSP like DCX2496 has far more gadgets in it if you really enjoy experimenting with sound.

[Eva]

If you don't fear DIY DSP, check out AK7744. I discovered this IC yesterday while I was reverse-engineering a Honda factory head-unit to add a line-input. I was not expecting at all to find such an IC in a factory head-unit, it seems very smart and it's 24bit 48Khz. Since it includes 3ch-ADC, DSP, RAM, 4ch-DAC, I2S digital audio input and output and almost everything in a single package, it may be controlled with just a PIC micro, a display and a keypad.

BTW: Alpine headunits employ a similar solution.