Nismo audio upgrade- critique my planned setup

bigaudiofanat

Still I have to say I would take focal over pioneer and polk any day after hearing the polyglass ones. Although the polk SR's are very nice.

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2fast4thelaw

I need to educate myself?? You and I are on a completely different playing field when it comes to SQ and car audio. You can think whatever you want, its really irrellevant to me.

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speedfreak28

Well Im glad we agree on something... Its not my point to cut you down but to be so close minded when there are ALOT of other products out there that can do the job better for less. Ive actually put together more than a few SQ cars, I dotn just make stuff up...

2fast4thelaw

I can tell from your last 3 posts that YOU don't have a clue on how to build a true competitive SQ system. Like I said, you and I are in a completely different league. Enough said!

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speedfreak28

This coming from someone who had a shop install do all the work. I bet your using passive crossovers for your competition sytem lol

speedfreak28

Lol, dunno why your so bent out of shape because I said there were a ton of cheaper, better options than your focals. Just because you bought an overpriced set of components doesn't make your car an award winning sq install. I'd love to see the how you have the speakers imaged and how the wires are ran and terminated. SQ is a lot more install then product used.

2fast4thelaw

There are many photos and unique designs in my audio system on this site that speak for themselves. Everything in my car has been designed and engineered specifically for my car. I have even shared my subwoofer enclosure design with some of you that took countless hours of design and engineering.

I had to have a shop do the fabrication and installation because fo one, I dont have a Machine shop and a wood shop at my disposal anymore, next I didnt have the time to strip my car down to deaden it.

I have done both active and passive cossovers on my fronts and I actually gained better results from the passives but my passives have been modified and redesigned by me to taylor them for the interior of my car and the thier location. So dont go there buddy! You are outta your league.

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bigaudiofanat

LOL speakers tailored for your car, doubt it. How they are aimed and setup that is something that I would believe. Speed knows what he is talking about and someone I talk to a for advice. So chill out!

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jikhead

Is this an East Coast vs. West Coast thing? Haha!

2fast4thelaw

You doubt becasue you and 95% of enthusiasts out there dont understand how crossovers really work. They do much more than filter frequencies. You can alter the phase and shift the time alignments on the drivers to compensate for tweeter location and for the material it reflects off of like glass vs plastic, leather, or even carpet. Crossover design is a science that is used in DIY world of car and home audio. Some people think its a bandaid solution and it is if you use inferior quality speakers ie "BOSE" but it does work!

I have been doing DIY for 15 years and I have developed my own custom software for crossover and enclosure design. If anyone is interested in it I might even share it.

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sobewebmaster

I'd like to throw in a suggestion for the component speakers, Infinity Kappa Perfects. Should be about the same price range as the Type-X.

Your best bet would be to hear them in person somewhere, like an audio shop. I love Alpine products, I have a complete Type-R setup (including vPower M500 mono amp & F300 4chan. amp, 12" Type-R sub, etc. etc.) and I absolutely love it. But I would really say, after hearing the Infinity Kappa Perfects powered from an Infinity 500w multichannel amp in a friend's GTO, I was just shocked at the clarity at high volumes, not to mention the bass they provided as well.

speedfreak28

Im curious how your changing the phase in your passive crossovers. The phase you can control through the crossover is electrical by utilizing different crossover slopes. You said you were using the focal passives so Im lost there.
Also phase as you refer to it being affected by the vehicles acoustics is not controlled through the crossover but rather through the install, aiming, and level matching primarily. Im also curious how you're utilizing time alignment with a passive network. You would only be able to adjust the stage left and right. Time and Frequency of a driver are two different functions, correct me if Im wrong. Also if you are using a passive filter time alignment wont help with height of your tweeter and the only way you can change phase without moving the tweet is to adjust the slope, affecting the electrical phase.

Again please dont take my comments the wrong way. I hope Im not out of my league because I'd like to think we can have an intelligent discussion. Id be curious about the program you made for crossover design. It could be a nice tool to add to my collection.

2fast4thelaw

I apologize if I came off a bit negative, anyway this forum is about sharing information and this is a bit lengthy so here goes.

The problem with stock passives is they are designed primarily for having the mid and tweet close to each other and on the same baffle or panel. This largely why they get a bad rap especially if you are forced to put components in unconventioal places. Basically a car is an unconventional envornment for audio. In order to resolve these problems we have to re-design our passive crossover network and taylor it for our envoirnment.

Phase and crossover slope are 2 separate entities and in this case slope remains unchanged.

Now adjusting the phase is a whole other science. Car speakers are optimized to perform well off-axis (speakers that play indirectly) vs home speakers that are optimized for on-axis (pointing directly at you). No matter how good off-axis speakers are, they will still sound better on-axis.

What I try to do is put the tweeter on axis by adjusting the phase anywhere between 90 and 270 degrees. In doing so this will change the time alignment between the mid woofer and the tweeter. You can calculate your resistor values that you will need to correct the change in time alignment. Let’s say you have a lot of carpet in your car, then you want your time alignment to be quite advanced because of the non-reflective materials in the car. If you are reflecting off of glass then you need to go the other direction because of the reflective material.

Applying this to the Z:

I chose to use the stock location for my mid’s and tweets. What I did was roll my tweets 270 degrees off-axis by changing the values in the resistors on the passive crossover. (I will explain why I did this later) Since they are reflecting off of glass I used the lower settings on the crossover volume to cut a little output from them to compensate for the db gain from the reflection from the windshield.

In the Z, the distance between the tweets and mid’s are about 18 inches but again the fact that they reflect from the windshield made the phase invert. I not only had to flip the phase 180 degrees to put them back into phase, but I added an additional 90 degrees to make the illusion that they were in front of my face. This was a total of 270 degrees of phase adjustment.
In order to get my values I had to reverse engineer the Focal passive crossovers.

These crossovers are 3rd order Butterworth 18/db octave crossovers so they were not that complicated. I just punched in the component values in my software and then my software program spits back the values after I have it calculate the phase I want.

I just had to order some 1% tolerance resistors and capacitors of equal quality and replaced the components.

This still changed some behavior of the tweeter and mid woofer relationship but remember I have a 13 band parametric eq which fixed this problem and I was able to blend them perfectly, at least to my ears.

My imaging is dead on and dramatically better than it was just rolling with the stock passives.

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speedfreak28

The problem with using the 13 band EQ through a passive filter ( Im assuming an eqx or something similar is that you are not adjusting the characteristics of the individual speaker but the whole passive network. this makes it really difficult to accurately tame peaks in an individual speaker because you will change the characteristics of the other as well. Heck, phase can change with frequency as it comes off a speaker. Also what may sound flat to you and imaged dead on may not be the same on an RTA. Realistically unless its a competition vehicle whatever sounds good to you should be your ultimate goal. SQ is subjective, measured SQ is not

2fast4thelaw

I had to heavily paraphrase to keep it from being a book but I will touch on your notes.

What i first was trying to say is I did not change the slope of the crossovers. Also Phase and slope only directly affect each other in simple passive crossovers without phase compensation. Any decent passive crossover will have phase compensation. In my Focal crossovers they compensated for that shift so I had to alter them.

Also since I have my own software I calculate time alignment by distance between tweeter and mid woofer becasue its a more stable constant since once the drivers are installed they will never move.

A Zobel network is already designed into the Focal passive crossovers because the Focal tweeters are actually 8 ohm and the woofer is 4 ohm. I altered the values in an attempt to undue the phase compensation that was designed into the crossover which put me exactly where I wanted to be at 270 degrees off-axis.

I left the mid woofers as they were (off-axis) as I only needed to alter the tweeters in my installation. I did this to keep it less complicated becasue I knew I could use my eq to blend them.

I wasnt using the EQX to tame individual speakers but to tame the peaks at each octave. I also first tune the system by my ear as what sounds best to me. I then record my settings as my reference point. If and when I have my car RTA'd for competition I can record those settings as a competition reference point so I can go back in forth. Perfectly flat is not always ideal for all music for everyday listening at least for my tastes.

Remember, there are a hundred ways to skin a cat. What I did made a big improvement and greatly enhanced my imaging and overal tonality of the system. If I could have in hindsight I would have used the 3-way Focal poly kev set and had even more improvement. I wanted to keep the stock appearence and that would have been nearly impossible.

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To the optimist, the glass is half full. To the pessimist, the glass is half empty. To the engineer, the glass is twice as big as it needs to be.