cheapest way to add time delay? any ideas?

[quins90lac 10+ year member]

Lol, noob??? I was sponsered for 2 years by infinity with a high in line called beta that you probably never heard of because only 52 elite infinity dealers in the US could carry it. That was 10 years ago and I still have my alpine digital time delay pra h400 processor from then when most people (probably including yourself quin) didn't even know what time delay was. Def not a noob but have been out of the game for a while. I just asked a simple question and if you don't know the answer "noobs" then don't reply.

cool story bro and lolumad

 

[Rich B 5,000+ posts]

I dont understand, you say you already own a PRA-H400 and those can delay up to 30ms, so why not use that?

 

[corcraft 10+ year member]

Jr

, wow! Another force beta fan! Not many people know what force beta is and when you say infinity they think of mediocre mids and harsh teeters. The beta was polar opposite great mids and mid bass (for there time) and the smoothest tweeters that I have ever heard. They were huge silk dome tweeters made by snell and those babies crossed over at 1,500hz with a xover that was way before its time; it was a 24db passive xover both adjustable for mids and highs. You're lucky, I wished I still had my beta stuff, I let it go with the car when I sold it like a dummy and all that I have left is a force beta neon sign in my basement. It wasn't just the mids and tweeters that were phenomenal the subwoofers are still some of the cleanest that I have ever heard and they sounded great in small enclosures. I had the amps as well, they were all digital, very powerful and actually surprisingly clean for being digital. I had everything beta and an alpine 7949, pra h400 and 2 of the alpine parametric eq's. As far as going back to ainet now- I want to keep my factory controls, I like the way that it looks and I have factory nav built into my head unit so my options on processors are limited.

KHL- I have built my share of precision enclosures and can measure speaker distance for "basic" time delay but I will have to admit that I wouldn't know where to start on measurements for time delay like you're talking about (I wish I did). I have always had good luck with the 20ms and adjusting from there. I will have to figure out how to get rid of the common mono signals for rear if I go this route but first I'm trying to find the delay which doesn't look to be simple or cheap.

X

 

[corcraft 10+ year member]

oops, sorry KHA! I wrote KHL earlier.

 

[VWBobby 10+ year member]

both are good reads. i still haven't seen a calculation for the delay, just a general rule of thumb that is combined with experience and equipment limitations. I like calculations, it shows there was some thought into the number(s) and helps you derive your own.

Why make a calculation if it still sounds like crap? I mean, most people who try to use the Alpine automatic acoustic adjustments IMPRINT™ technology say it kills their sound stage or kills their EQ settings. They complain of a flat sound. Then they have to blank out the settings and dial them in manually. If you have total control over the sound and can dial it in perfectly, I don't see the use. The processor the OP posted sounds like the best compromise for a computer controlled sound stage. It sounds like Alpine went to a lot of trouble to try to make each listener in the vehicle have a centered sound stage. I still have my doubts until I hear a unit like this. Sometimes I notice echo/delay in a digitally processed sound environment... I work on computers for a living, but find they are not worth the trouble when a human can do a better job. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Afterall, its all garbage in, garbage out.

 

[corcraft 10+ year member]

I dont understand, you say you already own a PRA-H400 and those can delay up to 30ms, so why not use that?

Because to use the delay by the pra-h400 you have to have ainet hooked up through a compatible deck. I'm wanting to use an oem interface processor. You can use the pra-h400 without ainet just not the time delay on it.

 

[ahole-ic]

Put a flux capacitor inline with your rear speaker wires. That will allow you to dial in the time delay you want, as well as travel time itself.

Win

 

[keep_hope_alive Premium Member]

Alpine processors are nice, but few work well without Ai-Net. the input sensitivity adjustments are always changing based on source recording level (to get the best gain structure).

I like to know why something works acoustically, since that's what I do. I understand that tuning by ear is always required and that math alone doesn't equate to perfect sound. i've been experimenting with mono rear fill in my setup using the center output of the H701. that means i have a dedicated 1/3 octave EQ, full bandpass crossover point and slope adjustment, and time alignment to 20ms. the drivers are 5.25" mids in sealed airspace located in factory 6x9 locations. i have plans for a custom rear deck with two drivers splayed in the middle of the rear deck (extension of third brake light housing). i'd like the rear speakers to be aimed so i can get maximum diffusion - i may aim them at the C-pillars then fabricate diffusion into the c-pillars.

if you want to see some of the latest and greatest in acoustical diffusion - check out

RPG Diffusor Systems

I've been experimenting with time delay for the rears lately, even more since this discussion. i've found settings i like from the driver's seat, but i need to listen from the passenger seat as well to nail down a setting.

 

[corcraft 10+ year member]

KHA, I know you have allot more knowledge than me and most of us on rear fill, acoustics is your specialty. So by you using around 20ms delay in rear kind of confirms my request. Now help me do it, lol.

 

[keep_hope_alive Premium Member]

i'm not going to say i prefer 20ms to another setting. i have to spend a lot more time with the car and the RTA to confirm any phase interference at either ear or either seat.

you have to be really careful with phase interference - it comes into play whenever you have reflections and split drivers playing overlapping frequencies. I have the advantage of an RTA for use anytime I want.

thanks for the complements. i am constantly learning, acoustics is a very exciting field that combines old knowledge with new concepts and applications. i just like passing some of that down to others who want to learn, in the hope they can teach me something in the process.

there must be a way to build a simple circuit that offers adjustable time delay, i'll see what i can find.

 

[whitedragon551 5,000+ posts]

Easiest way is to get rid of rear fill. Its only useful if your front stage doesnt blow and you need to raise the staging.

 

[dumple 5,000+ posts]

this is how i did my delay per eclipses instructions now I dont know where the 34 came from but it certainly made my vehicle sound better Refer to the following for the method of calculating the delay time.

A = (B-C) / 34

A: Delay time (ms)

B: Distance from the listening position to the furthest speaker (cm)

C: Distance from the listening position to the speaker to be adjusted (cm)

(Example) Listening position:

Driver's seat (left)

B: 200 (cm)

C: 50 (cm)

Delay time = 200 (cm) - 50 (cm) / 34

= Approx. 4.4 (ms)

 

[whitedragon551 5,000+ posts]

this is how i did my delay per eclipses instructions now I dont know where the 34 came from but it certainly made my vehicle sound better Refer to the following for the method of calculating the delay time.A = (B-C) / 34

A: Delay time (ms)

B: Distance from the listening position to the furthest speaker (cm)

C: Distance from the listening position to the speaker to be adjusted (cm)

(Example) Listening position:

Driver's seat (left)

B: 200 (cm)

C: 50 (cm)

Delay time = 200 (cm) - 50 (cm) / 34

= Approx. 4.4 (ms)

I believe it goes along with whats in my Alpine manual. It has to do with the speed of sound at sea level and converting between cm/in and ms. The speed of sound at sea level is 340.29ms. Centimeters divided by the speed of sound gives you milliseconds. If you do it Alpines way you divide by the speed of sound and then multiple by 1000 to get a ms time, by going with 34 they cut out the multiplication by 1000 to get a ms time.

 

[corcraft 10+ year member]

I used to have the rta luxury but lost my connection- actually the dealer went out of business. That was the good ole days I could just pull in a bay and use all of their equip and tools including a car lift no questions asked. Actually, I talked to my buddy today that used to be the manager and he's needing the money and knows I'm building another system so he's trying to sell me his mb quart qsd216 comps. They have killer, I mean killer mid bass and he'll let me get them cheap but I prefer silk tweeters so I'm leaning toward image dynamics xs-65, just haven't made the purchase yet. As far as my t/a dilemma, if all else fails I guess I could just drop the fill, go active and use my other amp for the front.

 

[Sarthos 10+ year member]

MiniDSP - miniDSP 2x4

Only $120. Gives a TON of processing features for not a bad price.