I couldn't decide between carpc or built in nav so I just went with the list below and the garmin nuvi nav thingy.

My system is now:
Alpine 9855
6.5 Boston Pro Compenent
5 1/4 Boston rears
Phoenix Gold Ti500.4
Phoenix Gold Ti600.2
2 x Elemental Design 10k.44

Starting with the amp setup, I have the ti500 which powers the 4 main speakers, set to full range and the crossover it at 240hz. The bass *** and sensitivity are both at min.
The Ti600 is set to low pass, and crossover is at 160hz. The bass and sensitivity **** are at min also.

Does that sound about right? My understanding is that the crossover FRQ is the "center" range...the higher being for the regular speakers and the lower for the subs. The range is 40-800 on the amps.

Manual for Ti500

Manual for Ti600

Now the HU is a bit more complex. I measured the distance in inches to each speaker from where my head goes and set up the timing pretty easily. But the crossover settings are beyond me.
Here's some screenshots from the online configurator that I can download into the head unit:



Any ideas on how I should set this up?
All xover/EQ settings on the HU are unchanged.
It sounds awesome but I'd really like to learn how to tune it myself.

 

What db roll off are the crossovers on the amps? I would be willing to guess that they are 12db. All advice will be based on that 12db roll off.

240hz on the front speakers is far too high. You can miss some male vocals even at this range and a LOT of the punchy "kick" bass range. Being that you have a boston pro set with some good power running to it you should certainly be able to run those front 6.5's down to AT LEAST 120hz ideally more like 80 to 90hz. Cars acoustically struggle to play the mid bass range (70-240hz) very well and sound quality competitors and audio freaks are always trying to find a way to get mid bass out of the rear of the car and in to the front stage.

Secondly asking your sub to play up to 160hz will make your bass very muddy and not very accurate sonically. Asking 10" of cone area to move at the speed that 150hz needs as well as 50hz is a tall order. You would be much better off using approximately 90hz as a rough starting point for your low pass crossover point on your subs and starting your mids around 100hz and experimenting. The lower your 6.5's can play the better your front stage (and ultimately your stereo) will sound.

I would recommend turning your gain down on your rear 5.25's (guessing channel 3/4) and crossing them over around 150-180hz. You could move them up a lot higher to keep them truly just "rear fill" (IE 600 or 800hz) Give your front stage a bit more gain to keep them the "dominate" speaker. Adjust your front and rear speakers first and get them a) how you want them to sound and b) as loud and more importantly as clear and distortion free as you can and then c) add your subs and tune them to accompany your front stage .. not over power it. All of this should be done with the head unit (pretty sure a max of about 35) in the 26-30 range. You want to utilize a stronger signal from your source to allow your amp gains to be ultimately lower which should result in cleaner sound and less distortion.

G'luck
Fej

 

Hi, I really appreciate your answer, great information!

I'm not sure what db rolloff is..is that crossover slope? If so it's 24db on both amps.

I'm still confused as to setting on the amp vs setting on the HU. Should I put both amps to "full range" thereby disabling the amp crossovers and then only use the crossover on the HU?

 

24db rolloff is pretty steep. Easiest way to expain is if you set your crossover on the amp at 100hz high pass (hp) and your system is playing at 90 decibels in theory a 100hz tone should play at 90db and a 63hz tone should play at 66db and get quieter from there. (think that makes sense) There are various octaves involved.

I would utilize both your head unit and your amps. Generally what I do is set my head unit at the desired crossover point, say 90hz for the subs. Then I set the low pass filter (LP) on my amp to just a tiny bit above that .. say 95hz. That way you are covered pretty well with both your signal from your HU and what it SHOULD be sending to the amp (IE 90hz and down only) as well as what the amp is allowing the subs to play (IE 95hz and down). The 24db rolloff is nice for the subs IMO.

I would use the head unit's crossover function first for the front stage as a 24db rolloff for the front mids may be a bit harsh and possibly create a small "hole" in your playback between 80 and 100hz. (I have one in my current install ... really shows up on certain cd's) A small overlap between what your sub plays and what your front stage plays in the bass range (20hz to 150ish hz) is a good thing IMO especially in a car which is acoustically not very good. I am guessing that the head unit is either a 12db rolloff or at most an 18db .. not sure. If your front speakers cannot handle 80hz then use the steep 24db rolloff on the amp and hardline them between 90 and 100hz.

So in theory it would look like this

Subs
head unit 90hz
Amp LP filter 95hz or so

Front 6.5's
head unit 80hz (start here and see how they play .. lot of distortion move it up)
amp HP filter 70hz (24db rolloff is steep but the headunit should govern it)

Rear 5.25's
head unit 250hz
amp HP filter 250hz

I did some more thinking and a bit of research on frequencies .. move your rear speakers up a bit higher. (edit)

You may be able to get away with around 150hz for the rears but you do not want to pull midbass away from the front stage by having the rear speakers help play it .. will cause imaging issues. (I personally never have rear speakers in my cars .. I never turn around at a concert for the "rear fill" effect either but that is just me)

Also it is highly recommended that in any high watt upper end install in a car that you AT LEAST sound deaden the doors some and the rear compartment, deck to lessen rattle and improve midbass.

If you really want to get technical you could go get yourself an RTA and find the acoustic peaks and valleys in the corvette .. spend 2 weeks experimenting with tweeter placement, build yourself some mid enclosures to improve their low end midbass response, and then get yourself an active crossover with 6,12,18,24 db rolloff options and play for a few weeks, or months, or years hehe.

G'luck
Fej

 

Thanks a ton for your time!
Can't wait to try those settings out tomorrow. It definitely has given me more of an understanding of how this all works.

 

wow... i wish Fej lived closer! This is some very informational stuff! I'm trying to tune my hpx-700 right now (what a bear) and this is ging to help me out some.

 

Thanks for the compliments guys ... I am a numbers guy and really like car audio .. especially the tuning of it because you can make such a huge difference with amps, gain settings, crossover points etc etc. I love taking friends systems and using my goofy "tuning" cd's that I know every note of and making them sound tons better. Home audio you just have to spend a lot of money to make serious improvements I have found. I am quite proud of my $1500 home system and its sound.

I however pale in comparison to some of the IASCA or USACI guys ... or the guys on TalkAudio.co.uk .... fanatics is all I can come up with heh.

I hope my numbers help .. each car tends to have its own issues .. whether it be resonance at certain frequencies or poor insulation or poor speaker locations .. but any car can be made to sound pretty damn nice with some good picks of equipment and good tuning. If I can stress anything about the advice I gave it is the midbass portion and getting your 6.5's to play as low as they can handle which will allow you to play your subs in the frequencies that they perform best in. One more thing with a 24db roll off you MAY be able to get away with a 70 or 75hz crossover point for your front speakers which would allow a nice 12 (or 18) db roll off from your headunit to your subs at say like 85hz. This would allow for a nice overlap of the midbass frequencies and keep your subs down in the hz range they like.


Scott I don't know the model well but I am willing to help pm me if you want.

Damado I believe that the 9855 also has some built in time correction. Read the manual about it and take some measurements, and WRITE IT DOWN (so you have it when you lose your deck settings heh) You have a better version of the time correction than I have on my 9815 and it made quite a nice difference in my WRX. Centered my soundstage I felt far better than it was without the time correction.

I really want to start my vette install ....

G'luck
Fej

 

Let me know how those settings go. I am kind of curious how the mid's sound with the rear speakers crossed up a bit higher like I edited into the last post.

If you want to get overwhelmed (even I am a bit) join talkaudio.co.uk forums and read their FAQ section about sound quality and crossovers and frequencies. Some of it I agree with completely but some of it is over the top pure competition stuff that in the real world sounds like *** (like a flat RTA ... sounds horrible to the ear IMO)

Fej

 

hey fej, if you ever have any free time it would be cool to have a basic tuning guide in the c5 faq.

 

Nice of you to ask bro .. I will see if I can get something typed up that fits a couple different install options and covers some basics. Probably next week. Hell what I should do it cut and paste up some of the stuff from talkaudio and then see if we can't apply it to the vette (fiberglass panels offer some "different" acoustics, plan on messing with my install a fair amount in the next month or so)

Fej

 

I also want to add one thing to this particular topic. All of this advice is based on what I have found to be functional in most cars and obviously what is good to my ear

This does not take in to account any of the typical issues surrounding car audio .. those things being road noise, exhaust noise, a left side biased main listening position, the acoustic "humps" associated with all of the plastic in the interior etc etc. The list goes on and on.

A competition sound system based on the RTA will generally not sound pleasing to the ear ... in fact I honestly feel it sounds horrible. The RTA for those that do not know analyzes specific frequencies and a portion of the judging is based on a smooth or nearly flat response line across the audio spectrum (20hz to 20k hz or thereabouts). Peaks and valleys with more than I think 2db between them lower your scores. It has been a long time since I did anything resembling competing however and things may have changed.

One of the biggest things you can do to improve your sound system is to add some sound deadening especially in the doors and rear hatch/compartment (wherever the subs are)

The next biggest thing you can do is manage your frequencies and which speakers play them. You can make a $1000 midbass sound like crap if you make it play the wrong frequencies. You can also make a $50 midbass sound pretty damn nice when tuned properly as well.

Most cars sound great with about a 42-45hz bass note. That is the note on a lot of rap or hip/hop that really hits. Many boxes are tuned around this frequency as most cars have a peak in the acoustics in this range. That is just ONE example of acoustic challenges in cars.

Anyways I will see what I can do for a tuning guide for the faq .. I know some of the other guys on here have a lot of knowledge on this topic as well I hope they chime in

Fej

 

If you are using crossovers that came with your speakers then I would suggest not using the crossovers and sound conditioning stuff in your HU. The crossovers that came with your speakers are probably matched perfectly with the speakers already.

 

Prism I am not familiar with the quality of the boston crossovers which I am sure are included with the component fronts but I can guarantee that they do not lowpass or "bandpass" the mid at an acceptable level from the factory. Most likely they only high pass the tweeter at their recommended level and they MIGHT lowpass the mid but most likely they do not.

It was an assumption on my part that he was using the passive crossovers included with the front 6.5's. Most of those crossovers are designed purely to protect the tweeter from playing frequencies that it can not handle and allow for some attenuation (adjustment) of the tweeter and/or mid volume for tuning purposes. They do not however control the midbass frequencies or the crossover points of the mids in ALMOST all cases. Something like the Utopia .be series might .. but 6.5's will run you about $4k a set

Anyone really serious about competition or high end fidelity will run active crossovers (which include in this case the HU and the amp filters).

I am guessing Prism that you mention to use the passive included crossovers to avoid any colorization or prevent damage to the tweeter which I assumed were in place and in this you are correct.

To only run "included" passive crossovers however is a mistake and could lead to potential system damage at high volumes.

Fej

 

I wasn't able to play with the system today, I'll try to get time tomorrow...seems like it's starting out to be a hectic week hehe.

One thing I'm dissapointed about is that the amp only goes down to 40 hz but will go up to 8000 hz (with the x10 switch on). Most subs are 25-35hz it seems. So this doesn't make sense to me. The alpine amps go down to 30 (I'm actually considering getting a couple of new alpine MRV/MRD series b/c of the other features they have like the AI-link for my HU etc).

On the HU, I'll start off with the settings shown in the picture. I'm not really sure how to adjust the -dB cuts or the dB/Oct....as you can see I have it on 24 now...not sure if they have the match the 24 rolloff of the amps.



The setting on the amps is not very accurate since it's impossible to tell exactly what I'm setting. it goes from 40 to 110 to 160 to 220 etc and I can't really tell where the line is..I dont' even thing the line lines up. But like you said before, the amp will be more of a "backup" to the HU's settings.

I'm reading some of the FAQs on that forum you listed...talkaudio.co.uk Thanks for that link, great information there. Hopefully I can get that website at work haha.

I'm also thinking about downloading a free real time audio spectrum analyzer to mess around with. Maybe it will show me what the dead Frq zones are since my ears might hear something lacking, but won't know what Frq range it is.

I'll try the free one at http://www.trueaudio.com/ using my laptop in the car.

And to answer the above, yes the boston pro 6.5s/tweeters use the passive xover they came with.

Thanks again!

 

I think you should raise your sub crossover point some ... you are getting a diminished playback db level across a very important portion of the bass spectrum. At least keep it above the 63hz octave.

I also think you should raise your rear crossover point some, start maybe around 150-160hz or so. Mids look like a nice starting point and if you can get them to play lower it would be a good thing.

We can actually only "hear" to about 20-22hz. Anything below that is basically just felt provided your subs can play it. CD's are recorded 20-20k hz for this reason that is the largest possible range a human can hear (think women hear slightly better than men .. men might cap out around 18.5 to 19k hz women slightly higher) I remember reading somewhere that a continous 14hz note can force you to throw up


I wonder if you can change the 24db value in that screen ... might be nice to start the mid at a less steep 12db roll off or so.

G'luck
Fej

 

Ok, messed with it a bit today. I started with everything zero'd out first.

Then I used:


Then I set it to the above. This was sounding pretty good, I just had to adjust the "sensitivity" on the amplifiers a lot. If I keep the sensitivity at min, the HU can be at full blast and it's hardly loud at all.

I also realized I had the x10 set on the amp which was giving me a 4000-8000hz range..so I moved that back to the 40-800 range. So the fronts are set to 110 or so on the amp 80 on the HU. The rears are 200 on the amp and 160 on the HU. The woofers are 80 on the amp and 63 on the HU.

I still only hear the deep bass I'm looking for accasionaly so I figure I still need to mess with the sensitivity/gain a bit more.

The treble is better but could be a bit clearer. It seems the mids are still dominating a tad, but it's miles ahead of what it used to sound like, thanks to your recommendations. The "punch" is incredible =)

I was tuning to some techno, hip hop, reggae, and what seemed to be the hardest to get right: Mozart's Requiem.

Oh I also tried these setting but didn't notice any difference:

I didn't notice the changes with the db rolloff...then again I'm not sure what I'm looking for.

 

A 6db roll off is pretty gentle. Generally used for the roll off on the top side of a mid in order to "band pass" it. IE 80hz crossover point at 24db roll off on the bottom side and a 6db roll off at say 4k hz to get a gentle transition in to the tweeter without asking the mid to play too high and without interfering with the tweeter.


Try an 18db rolloff at approximately 75 (or 80) hz on the sub. I think you may be missing some important notes out of the sub with it at 63. You need at least a 12 if not an 18 or 24db rolloff for the bottom of the mid at 80hz. The rears you could really mess around with and try something like a 6db roll off up around 180hz. Those are the speakers I personally have the least experience with.

The gains you should set with only the front speakers playing first and up near full volume (say 90 or 95% of max) then add the rear speakers gain to a comfortable, but not overpowering volume. Then finally blend the bass in to your mids to keep it from overpowering your front stage. Do this with the head unit sub setting in the +5 or so range. This will allow you to take some bass out when you need to (5 points) and add 10 more points (I think it is in 1/3rd db increments not sure) when you want to. The mids demand a LOT more watts to play at say a volume of 100db than the tweets do .. there is probably some sort of attenuation switch on your crossovers .. you might be able to drop your tweets by 2db or 4db since they are not individually amp'd to help smooth the sound out some.

Sounds like it is coming together nicely. We could get in to the debate on amp "headroom" etc when setting the gains but I have found that the lower you can set the gains and get a max volume that you like the better. Less likely to drive the amp in to clipping (distortion for your speakers) as well as keeping enough reserve power to handle big transients (big changes in music, both in note and volume).

G'luck
Fej