Sound Imaging, the evasive pleasure, how do I catch it?

[keep_hope_alive Premium Member]

You should lurk DIYMA forum. To be done properly in a car will always involve some sort of processor and almost always require some creative mounting of components. Selection of amps and components is way way down on the list of priorities to get it "right".
Throw your rear speakers out entirely unless you plan to play music that is RECORDED in 5.1 surround. What concert have you ever been to where the singer/drummer is behind you, or behind you and in front of you? It will invariably be an accoustic nightmare without carefuly selected source material and really good processing power.

except... rear fill should really be used to recreate a "room". we are used to listening to music in a room - where we get delayed reflections from behind us. the amount of delay gives us an idea of the size of the room we are in. that is how i use rear fill - to simulate diffuse room reflections to add depth to the sound stage and give the illusion i am in a space bigger than a car. full range drivers ran with a bandpass crossover can achieve this with careful level balancing. adding delay will allow you to simulate a larger space and take some control over the front soundstage.

getting diffuse rear information is the tricky part - and one that processing may play a role in. i may work on this a bit more - as an acoustical engineer i spend a lot of time designing/testing acoustical treatments for rooms and performance spaces. we also write our own simulation programs, and we can apply filters to program material to simulate a room. i'd like to design a rear fill processor some day that has all of the necessary controls/filters/effects needed to properly simulate rear reflections. just and issue of spare time.

 

[MediumTech 10+ year member]

except... rear fill should really be used to recreate a "room". we are used to listening to music in a room - where we get delayed reflections from behind us. the amount of delay gives us an idea of the size of the room we are in. that is how i use rear fill - to simulate diffuse room reflections to add depth to the sound stage and give the illusion i am in a space bigger than a car. full range drivers ran with a bandpass crossover can achieve this with careful level balancing. adding delay will allow you to simulate a larger space and take some control over the front soundstage.getting diffuse rear information is the tricky part - and one that processing may play a role in. i may work on this a bit more - as an acoustical engineer i spend a lot of time designing/testing acoustical treatments for rooms and performance spaces. we also write our own simulation programs, and we can apply filters to program material to simulate a room. i'd like to design a rear fill processor some day that has all of the necessary controls/filters/effects needed to properly simulate rear reflections. just and issue of spare time.

Wow, Thanks guys. This is certainly more stuff to consider. Thanks for the info.

 

[GammaRadiation 10+ year member]

Sound imaging is about stereo separation. Does the bassist sound right stage, lead left, vocals and drums center, etc... This is as much about the mastering of the track as it is the stereo it is played on, so make sure you've got a good track when determining imaging. It's going to be all about speaker placement and time delay. Yes, you want to minimize distortion, but simply for the sake of minimizing distortion. Getting near equal separation between the speakers and putting them as wide as possible will most often give you optimal results. High end head units also have time delays to correct for distances. Then there is also the issue of sound stage height. Ideally it should sound as if the music is coming from eye level. Unless your mids are on the dash and the tweeters are on the A pillars, this is very hard to replicate in a car. You can also improve your overall sound quality by lowering the noise floor. This means deaden everything, particularly large, flimsy panels such as door skins and the roof. A subwoofer that doesn't play too high is essential. If you're getting much response in the 80-120Hz range you're muddying up the sound stage for bass guitar. Steep roll off (18-24dB/oct) starting around 60Hz is my personal choice. The rest of your crossovers will have to depend upon the speakers you choose. I will promise you this, you're better off investing in a good active crossover compared to anything else. If you head unit has a solid crossover, even better.

 

[TaylorFade 10+ year member]

If you're more of a DIY kind of guy, the best money you can spend on processing is a miniDSP. You can get the 2 way active one (2x4) with the software plug in for ~ $110 shipped brand new. Time alignment, crossovers, reverse polaritys, a TON of EQ and more. The software has free lifetime upgrades too.

As has been mentioned, speaker placement and install is HUGE when trying to get an accurate and convincing soundstage. It can be done with the factory locations if you have the time and ear to get it right. I sat in the world championship "beginner" SQ vehicle at finals this year and it was amazing. In beginner class, you can only utilize the factory locations with an additional 1" tweet in the pillar. I honestly don't know how they did it. The stage was amazing and they even managed to accomplish "ambiance" with the factory locations and no rear speakers. Insane.

I have yet to experience a car with true "depth" that everyone talks about. Where certain material truly sounds like it's coming ffrom beyond the loaction of the drivers. Seems as if this is one of the most difficult aspects because physical location is so important there and there is only so much that procesing can do.

SQ is a fickle and mysterious mistress. Good luck tracking her down! My advice is to head over to DIYMA and start reading.

 

[keep_hope_alive Premium Member]

If you want to read more, don't start with DIYMA. There is some good info there, but also bad info, and if you don't know the difference then the source isn't useful. Pick up a book on acoustics. PM me for some reference material recommendations.

This is from the 09 edition of NFPA seventy-two. We care about room acoustics, location cues, intelligibility, etc. for fire alarm and mass notification speaker systems. Building a stereo is one thing, designing a life saving speaker system is another!

 

[MediumTech 10+ year member]

Cool info, Thanks again.

 

[MediumTech 10+ year member]

Well, I just bought an eclipse 7200 mkII

Should be installed tomorrow.//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[keep_hope_alive Premium Member]

it is a nice piece. the faceplate mechanism is cumbersome and may interfere with some dash kits - but that is a small price to pay for a good SQ unit.

 

[MediumTech 10+ year member]

delay on installation: the eclipse should be in this week sometime

 

[duanebro 10+ year member]

delay on installation: the eclipse should be in this week sometime

Sorry to hear that, I hate waiting to get a new toy installed!

 

[MediumTech 10+ year member]

Sorry to hear that, I hate waiting to get a new toy installed!

Yeah, the installers (or at least one of the lazy ones) told me they ended up booked-up on Saturday, and advised trying again another day.

Installers and waitresses should not be pissed before you receive service right?

 

[MediumTech 10+ year member]

the new sound system is in.

I am very impressed.

I am especially impressed with this eclipse 7200 head unit.

this is the best sound system I've ever owned.

thank you all for your help in developing this

 

[dumple 5,000+ posts]

now get it all tuned up and youll be having eargasms

 

[MediumTech 10+ year member]

now get it all tuned up and youll be having eargasms

I bought the eclipse cd 7200 mk2 at a $200 discount from a shop that had it as their demo unit.

I got the remote with it, and now I need to print a manual to learn the k-nobs and buttons.

Eargasm's- is that where ear wax comes from????

I've got FL & FR time delay set at 4.0 m/sec, and vocals seem to be coming out of the windshield and door glass....

 

[mylows10 5,000+ posts]

nice glad to hear it all came together for you.