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Old 11th September 2009, 00:37   #31
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Originally Posted by greenh0rn View Post
Man you sure seem to know exactly what I need!

Well, that's a very general manner. With more EQ bands you can cut or boost particular freq. to get the best out it. Let's say the midbass you have may not sound the same in another car or rather it's door. Reflection and cabin gain is again different in every car. That's one of the reason it's wise to have L-R independent xover to tune the sound. This may take several hours of listening few SQ tracks. I would liked to have atleast 5 band P.Eq on Clarion but unfortuneately it ain't gonna happen.

How on mother earth do I make the tweeters stick to A-pillar above the dash (it's a Santro)? They just fall off the double tape, or even bring the tape down with them.
Well, I suggest stick with a big patch of double tape for testing purpose so that it supports the weight of the tweeter. Listen to it without any EQ, TA. After listen to the same track again using the TA followed by EQ. See, if it helps.


I don't know the exact volume but it definitely is less than 1.4, perhaps even less than 1.2 cu.ft. What effect would lowering the volume have on sub performance?
Can you just measure the outer dimension and the thickness of the wood used? Rest I will figure out. 1.4cu.ft would give you a good flat response and better low end and since there is always a lot of cabin gain with the hatchback as compared to the sedan you would see better low end extension. Going lower than 1cu.ft will boost the freq above 50 hz going upto 100hz, this might make the sub sound bit boomy, muddy or whatever you wanna term it as. To have a smooth linear extension I suggest use 1cu.ft and add some 1.5 pound of polyfill to make up for the larger enclosure.
Another reason could be that the metal in the booth needs more damping. Upto mid volume the low freq will sound great but once you start pushing it the low end would tend to sound muddy or rather won't sound clean. Adding some more damping and closed cell foam might help.


Definitely, my To Do #1 for this Saturday.

I am sure these parameters can be found out easily. But how far does going active actually benefit the sound stage?
Getting the parameters as in what freq the midbass and tweeter, "Fs" would help in determining the roll-off freq and what slope can be used, and the power rating to help as to how much power can be given.
My answers in Bold.

http://www.team-bhp.com/forum/sound-...ml#post1476592
Answer to your query in the above link.

Also, like to add that going Active means using the digital xover on the headunit by eliminating the passive xover. Setting up active in your case would be front 2 way and sub. You will need to determine what freq. the tweeter and the midbass can handle. Than you can always play around with different freq. point. Once you set the xover points you can individually set the gain and TA on each tweeter and midbass. That way you can manage to get the the precise center stage. Also, setting the midbass first and than determine and match the level of the tweeter that way you would know how much power the tweeter needs. Active setup can take days to get it right and precise.
Ideally the soundstage has to be in center of the dash, close the rear view mirror (atleast that's what I prefer) but the other parameters like cabin gain and reflection, placement of the speakers, will determine where you can get the soundstage.. high above or on the dash.
Also like to add that the rear speakers if tuned correctly by band-limiting i.e. sticking to particular low pass and high pass filter, correct amount of gain, TA, running them out of phase, at times even giving them mono signal can help to enhance the soundstage in front. It can give an illusion of wider soundstage, as though you sitting in bigger car, lifts the imaging up, adds cleaner vocals and depth. But this has to be done very precisely. There are processors like 1.Bit, RF 3sixty.3, Audiocontrol DQXS, and the upcoming still to be released JBL MS8 that will make use of the rear speak in adding more depth to it.
For your reference I am using the rear speakers on the same Clarion 785 and honestly speaking would never want to listen to music without it. I have the front and rear and sub running in Active mode or rather actively passive. The imaging is bang at the rear view mirror in center and much wider
Anyways, I don't want to complicate this further as this could be a very debatable issue.

Last edited by Invinsible : 11th September 2009 at 00:54.
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Old 11th September 2009, 11:03   #32
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Thanks so much, Invinsible, really appreciate your time and effort in posting these hugely informative posts.
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Originally Posted by Invinsible View Post
Can you just measure the outer dimension and the thickness of the wood used? Rest I will figure out. 1.4cu.ft would give you a good flat response and better low end and since there is always a lot of cabin gain with the hatchback as compared to the sedan you would see better low end extension. Going lower than 1cu.ft will boost the freq above 50 hz going upto 100hz, this might make the sub sound bit boomy, muddy or whatever you wanna term it as. To have a smooth linear extension I suggest use 1cu.ft and add some 1.5 pound of polyfill to make up for the larger enclosure.
I'll do it tomorrow morning and post it here. Will the formula of trapezoid work?

Also I can feel the boomyness (or in-cabin resonation) at a particular low frequency (occurs in a few songs)- might use a test (sine) tone to figure out the exact frequency. The sub's FS is 25 hz, and the recommended enclosure volume given on GZ website is 0.7-1.4cu. ft. I think mine is about 1cu ft or slightly less. http://www.ground-zero-audio.com/13_...gh_gztw30t.pdf

One more interesting observation, this above link shows a green light to ported enclosure for this sub, but only a yellow light to sealed. Does that mean the makers are recommended a ported box?

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Originally Posted by Invinsible View Post
You will need to determine what freq. the tweeter and the midbass can handle.
I can check with LBM or Ajay for this- shouldn't be a problem.

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Originally Posted by Invinsible View Post
Ideally the soundstage has to be in center of the dash, close the rear view mirror (atleast that's what I prefer)
Whoa! If this is indeed the case, i am really going to go pursue this ideal!

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Originally Posted by Invinsible View Post
Also like to add that the rear speakers if tuned correctly by band-limiting i.e. sticking to particular low pass and high pass filter, correct amount of gain, TA, running them out of phase, at times even giving them mono signal can help to enhance the soundstage in front.

For your reference I am using the rear speakers on the same Clarion 785 and honestly speaking would never want to listen to music without it. I have the front and rear and sub running in Active mode or rather actively passive. The imaging is bang at the rear view mirror in center and much wider
How can I do that (run active-passive, or sub+front stage active and rear passive) in this Clarion and still have control over rear speakers in terms of lpf/hpf? The 3-way speaker setting in Clarion will allow only front tweeters, front woofers and sub, while 2-way adds in rear speakers, but subtracts the sub! I think the only option for me would be to use fader, or else use a separate 2-ch amp with variable filters to drive rear speakers (not something I am keen to add).

Invinsible, there is another interesting article that I want to bring to your attention- quoting from it:

Quote:
because the sound waves from both your speakers are colliding with each other and due to the phase angles not lining up with each other they will add and subtract from each other, not necessarily amounting up to more volume. Again more speaker and power will not alleviate this effect. This also causes severe deviations of amplitude at higher frequencies causing what is known as the comb filter effect. When comb filtering happens your brains ability to sample that sounds qualities is greatly diminished because much of the information is either physically being destroyed due to phase cancellation or being discarded by your brain as it is perceived as invalid. This will actually make your highs sound metallic and harsh not to mention trashing any chance that you have at good imaging or authoritive mid bass.
I suspect that comb filtering could be one of the reasons why I am missing the pounding drum a bit, even at high volumes. The article is here how to achieve awesome mid bass
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Old 11th September 2009, 12:04   #33
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One of the best articles on phase-shifting, phase-cancelling and polarity reversal I've seen-

Moulton Laboratories :: About Comb Filtering, Phase Shift and Polarity Reversal

Another one- this one's featuring a calculator for phase shifting (not useful for us though, as the top article seems to explain

Phase angle calculation from time delay and frequency calculate phase difference time of arrival ITD phi phase shift - sengpielaudio

Last edited by greenh0rn : 11th September 2009 at 12:10.
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Old 11th September 2009, 13:03   #34
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Originally Posted by greenh0rn View Post
I'll do it tomorrow morning and post it here. Will the formula of trapezoid work?
Just post the outer dimension of the enclosure and thickness of the MDF used will let you know what the internal volume could be.

Quote:
Originally Posted by greenh0rn View Post
Also I can feel the boomyness (or in-cabin resonation) at a particular low frequency (occurs in a few songs)- might use a test (sine) tone to figure out the exact frequency. The sub's FS is 25 hz, and the recommended enclosure volume given on GZ website is 0.7-1.4cu. ft. I think mine is about 1cu ft or slightly less. http://www.ground-zero-audio.com/13_...gh_gztw30t.pdf
Here's the thing, the enclosure size of 1.4 cu.ft is measured in regards to Qtc of .707. Why point .707 well In the case of a tuning quality Qtc of 0.707 results a frequency response, which runs as for a long time as possible linear and then fast drops (Butterworth alignment). This is what is kept in mind when designing a Sub enclosure for home audio. Incase of car audio there could be a cabin gain upto 10db. In your case the GZ website mentions sealed enclosure of .7 to 1.4 which means that 1.4 is what is calculated with Qtc of.707 where as .7 cu.ft enclosure is achieved keeping the Qtc at .9. With Qtc of .8 you can achieve an enclosure of 1.cu.ft. Bigger the enclosure better will be the low end extension and more linear. This may make the sound less punchy but will sound more deep and low and much cleaner and will blend well with the front stage better. Smaller you go you will give up bit on low end and the bass can be termed to sound "boomy" as the the signals gets boosted little above 70hz. In which case you can make use of poly-fill in 1 cu.ft to make up for optimum size of enclosure needed. The sub can be used for both sealed and ported.

Why don't you add some polyfill to you present enclosure and see if it improves the sound. Start of with 1 pound of polyfill.



Quote:
Originally Posted by greenh0rn View Post
I can check with LBM or Ajay for this- shouldn't be a problem.
This would help you in determining the tuning while going Active and who can help in this case better than LBM and Ajay.

Quote:
Originally Posted by greenh0rn View Post
Whoa! If this is indeed the case, i am really going to go pursue this ideal!
Atleast, that's what happening to my soundstage and I like it that way

Quote:
Originally Posted by greenh0rn View Post
How can I do that (run active-passive, or sub+front stage active and rear passive) in this Clarion and still have control over rear speakers in terms of lpf/hpf? The 3-way speaker setting in Clarion will allow only front tweeters, front woofers and sub, while 2-way adds in rear speakers, but subtracts the sub! I think the only option for me would be to use fader, or else use a separate 2-ch amp with variable filters to drive rear speakers (not something I am keen to add).
Well I am running Front Comps, Rear coax in doors, and a Sub in "3 way Active mode" from the headunit instead of the "Normal mode" on the headunit. This way I can get to set the xover point from the headunit.
The Front comps are running through their passive xover under the "High" freq. setting on the headunit with HPF of 63hz at 18db.
The rear coax are band-passed under "Mid" setting with HPF set at 160hz at 18db and HPF at 4000hz at 12db and are running out of phase. SInce it's band limit there is not much of high freq. being played which also helps in keeping away the stage being pulled at rear.
The sub is being used under the "Sub" setting with HPF at 16hz and LPF at 63hz or at times 80hz at 18db. It's only when I listen to Pink Floyd I take it upto 100hz while adding some more kick to the midbass
By running under 3 way mode, helps me as I mentioned to make the the changes on front comps by shifting HPF xover point on them depending upto the music I play while I am seated. Another advantage I get is L-R independent P.Eq setting which can be done as desired
and gain setting of individual channel that is FL, FR, RL, RR and sub. And ya this would require 6 channels of amplification.
In your case if you just plan to run the front comps and sub you can use it in normal mode.

Quote:
Originally Posted by greenh0rn View Post
Invinsible, there is another interesting article that I want to bring to your attention- quoting from it:

I suspect that comb filtering could be one of the reasons why I am missing the pounding drum a bit, even at high volumes. The article is here how to achieve awesome mid bass
It just boils down to one thing Phase Shift, comp filtering is a by product of it.
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Old 11th September 2009, 13:05   #35
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Arre guys I am waiting for your feedback and suggestions, please help me tune the system properly! Navin sir, DerAlte sir, LBM, Frank, Autophile, thodi kripa drishti (benign gaze) on my thread also please...
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