7 replies to this topic

[REVNSS.inc]

I have been doing a bit of research lately in regards to using rear fill to enhance the front sound stage.

In particular I've been reading about the Haas effect, delay and L-R difference signals and how they can be used to create ambience, increased depth or perceived loudness.

Has anyone tried out any of these methods and what were their findings? Or even experienced members thoughts on the matter?

Josh.

[MAS Andrew]

I've done this in a few cars. It really depends on the vehicle. You can get great results but you need a sedan with parcel shelf mounted speakers, as far apart as possible.
You can get excellent results.
PM me for more

[TMM]

Pulls back the soundstage, can provide a boost to midrange,

Can be good/bad depending on user preference

[Frankston Car Audio]

You may remember I was experimenting with this in the Astra Wagon a couple of years ago, Josh.. (before the Civic)
I spent around 18 months trying to get it "right"..and never really did

It did add height, width and helped with focus but it requires a fair amount of tweaking with delay (more than many current processors can provide), band limiting and other factors. to achieve.
Essentially this is the precursor to the current Dolby Digital (it is essentially the same principle used in the original Dolby Surround)

You are better off getting the "foundations" correct (speaker placement, axis, mounting etc) to achieve a decent staging, imaging and focussed stage in any vehicle.
Electronics can be handy to "fix" some problems.. unfortunately, these days too much reliance is given to this

. at least that's my opinion

Mark

[ubernoob]

I was having a play with rear fill but most of the time my rear seats are down and it did more harm than good and I am too lazy to buid a sealed enclosure for the rear speakers.

[Big_Valven]

I played around with it in my Commodore - basically bandlimited and out of phase with the fronts. My limitations :-

No processing
Rear speakers in bottom of rear doors
Factory rears - sound like poo.

It DID image better than with just the fronts. The judge didn't pick they were there either... The width was better and there was some increase in depth. It didn't drag back as much as you think.

It improved imaging considering I was using a cheap pair of splits, passive, no processing, in factory locations. I imagine it would take much more work to get right in a high level system.

[Tiger]

Simple... I use my rear fill to compensate for the front stage I don't have.... by using multiple drivers hahaha..


As above..... it's a fine line though.... one small error, and you'll see your stage go straight over your head... and right to the back.


More trouble than it's worth in all honesty. But hey... if you have the time/patience/car for it... go for it and let us in on the success story

[br85]

As it has been suggested: Pretty much don't try this until everything else is 100% the best you're going to get it. Also, try to use similar timbre drivers that you're using for midrange in the front. A little experimenting I've done suggests 17-30ms delay is required, about 400-5k bandwidth (and identical to the front FR within that bandwidth - you MUST use an RTA) and at least 5dB or more down from the front stage levels.