Going active - which processor?

[fatryan 5,000+ posts]

comps are Rainbow CMX kicks 2-way, amp is PG Xenon x200.4, HU is 9800BT (not active capable). just trying to get some opinions on an external processor. someone recommended a Memphis 16-x03, and ive seen it mantioned a couple other times in other threads. what are your opinions? would you recommend anything over this, and why? the memphis is quite pricey but if it means it wont quit on me and damage my comps, its worth it.

also, im assuming i will need 2 sets of ~1ft rcas. anything else? i wont be running my sub stage through this (if that is even possible).

i plan to just be safe and cross the components where the passive Xover does (3200hz @ 12db per octave i believe). mids will also be set to not go below 80Hz with a 12dB slope (as rainbow requires for the kick version). but my question is, when the mid and tweet are crossed at 3200Hz that means they BOTH drop off at that point? and both require a 12dB slope? and is that where the drop off begins? or is that some other point in the slope, like -3dB?

TIA //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

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[Fast1one 10+ year member]

I mentioned before the Memphis is probably your best bet for the price...

As far as your questions, the crossover point is the -3db point. Depending on the crossover, you can over and under lap the crossover points. For example, you can cross over the mids at 4khz and the tweets at 3.5khz, which is great because you can tailer the crossover points to your speakers and vehicle...

I wouldn't worry too much about slopes just yet, so long as they are atleast 12db/octave (like the passives). Simply put, you aren't going to have very many options until you buy an active capable deck. For example, the Memphis has fixed slopes of 18db/octave for the mids/highs and 24db for the subwoofer...

http://cgi.ebay.com/MEMPHIS-AUDIO-16-XO3-3-WAY-ELECTRONIC-CROSSOVER-REMOTE_W0QQitemZ300214466796QQihZ020QQcategoryZ79840QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

[fatryan 5,000+ posts]

I mentioned before the Memphis is probably your best bet for the price...
As far as your questions, the crossover point is the -3db point. Depending on the crossover, you can over and under lap the crossover points. For example, you can cross over the mids at 4khz and the tweets at 3.5khz, which is great because you can tailer the crossover points to your speakers and vehicle...

I wouldn't worry too much about slopes just yet, so long as they are atleast 12db/octave (like the passives). Simply put, you aren't going to have very many options until you buy an active capable deck. For example, the Memphis has fixed slopes of 18db/octave for the mids/highs and 24db for the subwoofer...

http://cgi.ebay.com/MEMPHIS-AUDIO-16-XO3-3-WAY-ELECTRONIC-CROSSOVER-REMOTE_W0QQitemZ300214466796QQihZ020QQcategoryZ79840QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

i dont doubt that you made a good recommendation man, i just wanted other opinions y aknow. and d@mn thats a good price lol! i may just have to snag that up.

wasnt aware that they would have set slopes. so you think i should still cross them at 3200? i really dont want to risk hurting anything even if i could push it a little further b/c of the 18dB slope.

kinda OT, but you happen to know what to cross my Q's at? i tried emailing Fi but they never responded. currently i got em at 80Hz @ 12dB slope. but i was wondering if 12dB isnt steep enough.

 

[Fast1one 10+ year member]

i dont doubt that you made a good recommendation man, i just wanted other opinions y aknow. and d@mn thats a good price lol! i may just have to snag that up.
wasnt aware that they would have set slopes. so you think i should still cross them at 3200? i really dont want to risk hurting anything even if i could push it a little further b/c of the 18dB slope.

kinda OT, but you happen to know what to cross my Q's at? i tried emailing Fi but they never responded. currently i got em at 80Hz @ 12dB slope. but i was wondering if 12dB isnt steep enough.

Of course man! I have no problem with getting other opinions hehe...
I think you should stick to 3200ish first then play around, but don't stray too far below 3k with the tweeter...the woofer you can play with though, try everything from 2.5k-5k and find what sounds best to YOU....

The subs should be crossed low enough to be transparent (meaning you can't really tell where its from), but high enough to augment the midbass coming from your mids if you want more impact...especially with rock and such...

Can't really give you a direct answer with that one. Like the woofers lowpass, best to just experiment. I would work with the woofers first, then blend in the tweeters, and finally blend in the subs.

Play with ALL phasing configurations. For most cars, with mids in the doors and tweeters up high, tweeters out of phase and passenger side woofer out of phase seems to work best. You will loose some midbass in exchange for better midrange, but again you can use your subs to fill in some of the midbass...

Experimenting is Key in this hobby...

 

[WrenchGuy 10+ year member]

I have the Memphis and it works great and attenuates well. I have no problem saying get it.

 

[fatryan 5,000+ posts]

Of course man! I have no problem with getting other opinions hehe...
I think you should stick to 3200ish first then play around, but don't stray too far below 3k with the tweeter...the woofer you can play with though, try everything from 2.5k-5k and find what sounds best to YOU....

The subs should be crossed low enough to be transparent (meaning you can't really tell where its from), but high enough to augment the midbass coming from your mids if you want more impact...especially with rock and such...

Can't really give you a direct answer with that one. Like the woofers lowpass, best to just experiment. I would work with the woofers first, then blend in the tweeters, and finally blend in the subs.

Play with ALL phasing configurations. For most cars, with mids in the doors and tweeters up high, tweeters out of phase and passenger side woofer out of phase seems to work best. You will loose some midbass in exchange for better midrange, but again you can use your subs to fill in some of the midbass...

Experimenting is Key in this hobby...

what do you mean by the phasing? like wiring 180deg out of phase? or simply messing around with TA?

 

[fatryan 5,000+ posts]

I have the Memphis and it works great and attenuates well. I have no problem saying get it.

cool thanx //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[Fast1one 10+ year member]

what do you mean by the phasing? like wiring 180deg out of phase? or simply messing around with TA?

Just messing around with 180 deg phase shift (wiring speakers out pf phase)...
The thing is, the human brain decodes the audio spectrum in different manners. To FULLY enjoy solid imaging in the center, you need to be able to attenuate frequencies above ~500hz so you can match the loudness of each speaker (since the driver side speakers are closer). This is why its so beneficial to go three way, because anything below around ~500hz (some say as low as 200hz) is distance dependent (meaning you would need T/A) while everything above that point is just based on perceived loudness...

Won't dive to far into the subject though, since you have a 2 way front stage and a deck that isn't active capable your options are limited. It should still sound great, but the only thing you can play with are crossover points and phase...good luck //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[fatryan 5,000+ posts]

Just messing around with 180 deg phase shift (wiring speakers out pf phase)...
The thing is, the human brain decodes the audio spectrum in different manners. To FULLY enjoy solid imaging in the center, you need to be able to attenuate frequencies above ~500hz so you can match the loudness of each speaker (since the driver side speakers are closer). This is why its so beneficial to go three way, because anything below around ~500hz (some say as low as 200hz) is distance dependent (meaning you would need T/A) while everything above that point is just based on perceived loudness...

Won't dive to far into the subject though, since you have a 2 way front stage and a deck that isn't active capable your options are limited. It should still sound great, but the only thing you can play with are crossover points and phase...good luck //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

i thought wiring 1 out of phase would cause destructive interference and significantly affect the amplitude? and isnt the whole point in TA to solve the above mentioned problems? lol

 

[Fast1one 10+ year member]

i thought wiring 1 out of phase would cause destructive interference and significantly affect the amplitude? and isnt the whole point in TA to solve the above mentioned problems? lol

T/A is totally overrated...it can be effective when used in small amounts but people use it as if its Gods gift to car audio...
A simple experiment would be to use a home audio setting. Move one speaker a few feet closer to you then use the balance to attenuate the one closest to you...

You should still get pretty solid imaging at the listening position once you get it dialed in correctly...

Its not a perfect experiment, since most rooms are not perfectly symmetrical, same goes for cars. To REALLY do it effectively is to use an RTA and a 1/3 octave EQ PER SIDE...then you can gain match right down to the frequency to get flat response. Then EQ to taste...

The phase issue is only valid when:

A: The speakers share an enclosure and

B: When the speakers are the EXACT same distance and angle from your ear...

The latter simply isn't possible in a car, unless you drive in the center //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[audioholic 5,000+ posts]

T/A is totally overrated...it can be effective when used in small amounts but people use it as if its Gods gift to car audio...
A simple experiment would be to use a home audio setting. Move one speaker a few feet closer to you then use the balance to attenuate the one closest to you...

You should still get pretty solid imaging at the listening position once you get it dialed in correctly...

Its not a perfect experiment, since most rooms are not perfectly symmetrical, same goes for cars. To REALLY do it effectively is to use an RTA and a 1/3 octave EQ PER SIDE...then you can gain match right down to the frequency to get flat response. Then EQ to taste...

Your home audio experiment is flawed. If you move one speaker closer to you, and then merely adjust output levels (attenuation etc), pathlength differences will cause problems in your sound stage. If its enough to be noticeable or not would depend on many factors.
I agree T/A tens to get overrated, but it can and is a valuable tool to use when done correctly. It is overrated, but it is also very necessary in many cases.

 

[Fast1one 10+ year member]

Your home audio experiment is flawed. If you move one speaker closer to you, and then merely adjust output levels (attenuation etc), pathlength differences will cause problems in your sound stage. If its enough to be noticeable or not would depend on many factors.
I agree T/A tens to get overrated, but it can and is a valuable tool to use when done correctly. It is overrated, but it is also very necessary in many cases.

Path length differences only become an issues because of early reflections from the room, and the general unsymmetrical shapes of rooms.
A big misconception is that path length differences pay a roll THROUGHOUT the audio spectrum, when in reality they don't (ony from ~500hz and below, like I mentioned before)...not saying you shouldn't aim for the lowest path length differences, because it would make it a lot easier when you get to tuning...

Some good quotes from the werewolf:

A brief review of dominant hearing mechanisms is in order. For the purposes of this discussion, it's VERY important to decompose hearing localization into two dimensions : lateral and vertical. I think the most important points are these :
1. Localization cues in the lateral plane are dictated by the differences in the acoustic transfer function to our two ears. These include inter-aural time differences, mostly significant for lower frequencies in the midbass and lower midrange, and inter-aural level differences, mostly significant for higher frequencies in the upper midrange and treble.

2. Localization in the vertical plane is dictated primarily by the shape of our outer ears and torso. Please consider that, if our outer ears and torsos were absent, we would be left with the classic "sphere with holes in the sides" for our heads ... and the symmetry of this geometry would absolutely dictate that vertical localization would be impossible. It's my understanding that the outer ear has the largest impact on the acoustic transfer function for vertical localization ... and given the dimensions of the outer ear, this implies that vertical localization cues are only significant above ~1kHz or so.

And our very own Devil Rider, I think his explanation is a little simpler:

Just some comments on psychoacoutics if they haven't already been mentioned....
Imaging clues of near-field sources come from ITD and IID (Interaural Time Difference and Interaural Intensity Difference, respectively).

ITD is typically used by the brain to localize low frequency sources (ie. below 500hz).

IID is typically used by the brain to localize high frequency sources (ie. above 1khz).

So what does this tell you? Well, for low frequency content that is localized by ITD (ie. lower midrange and midbass), it is imperative that PLD (Path Length Difference) is as equal as possible. Of course, physical equality is best... But for high frequency content that is localized by IID, SPL is the key factor: if you can get SPL equal at the ear from the left and right sides, there should be fairly little difference.

Of course, above 4khz, frequencies are attenuated by the head for the far side ear. A sound to your left will appear to have different spectracl content compared to the right ear. This is called HRTF (Head Related Transfer Function) and depends on the shape of your head.

Neil

This is why experimenting with positioning is the MOST IMPORTANT step in car audio reproduction. T/A is just a band aid...along with EQ to an extent(its a must in car audio though)...this is also why going 3 way is so important. You can compensate for path length differences for midbass with T/A, gain match with EQ for the mids, and get solid vertical cues with tweeters in the A-pillars for example...

 

[audioholic 5,000+ posts]

You are suggesting time differences play no role above 500hz?

 

[fatryan 5,000+ posts]

T/A is totally overrated...it can be effective when used in small amounts but people use it as if its Gods gift to car audio...
A simple experiment would be to use a home audio setting. Move one speaker a few feet closer to you then use the balance to attenuate the one closest to you...

You should still get pretty solid imaging at the listening position once you get it dialed in correctly...

Its not a perfect experiment, since most rooms are not perfectly symmetrical, same goes for cars. To REALLY do it effectively is to use an RTA and a 1/3 octave EQ PER SIDE...then you can gain match right down to the frequency to get flat response. Then EQ to taste...

The phase issue is only valid when:

A: The speakers share an enclosure and

B: When the speakers are the EXACT same distance and angle from your ear...

The latter simply isn't possible in a car, unless you drive in the center //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

well regardless of what degree the signals are out of phase, if they reach your ear at 180deg out of phase there should be destructive interference. we actually just went over this in optics today lol. i know light and sound are 2 different animals but the principle is the same.

it just seems like wiring 180deg out of phase would be WAAAY too much of a phase change and would completely destroy the sound. i mean the difference in distance between the person and the left speaker vs the person and the right speaker is pretty minimal when comparing the speed at which the waves travel...

 

[Fast1one 10+ year member]

You are suggesting time differences play no role above 500hz?

Of course not, but when compared to the effect of level matching its fairly insignificant because the cabin is a relatively tiny space...
If you can get the SPL levels of the left and right midranges equal to your left and right years respectively, you will get fairly SOLID center imaging, so long as you take care of early reflections (I.E. Foam products)...

well regardless of what degree the signals are out of phase, if they reach your ear at 180deg out of phase there should be destructive interference. we actually just went over this in optics today lol. i know light and sound are 2 different animals but the principle is the same.
it just seems like wiring 180deg out of phase would be WAAAY too much of a phase change and would completely destroy the sound. i mean the difference in distance between the person and the left speaker vs the person and the right speaker is pretty minimal when comparing the speed at which the waves travel...

Thats the thing, you simply can't make assumptions about absolute phase until you have the speakers mounted in the position you want and you start testing...a full 180 degree phase shift may be too much, in which case T/A (a very LITTLE amount) can be used (usually passenger side works best)...
You CAN have a great sounding system without T/A though. Which is what I am getting at. Level matching with midranges is much more significant than applying T/A. In addition, playing with relative phase of the speakers is a rudimentary way of applying time alignment...

For now, just go active with a simple crossover, because once you get sucked in you will spend HOURS trying to get concrete imaging while maintaining tonality...not to mention it will dent your wallet //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif