Electronic Crossover Tuning Problem

[xxyue188 10+ year member]

I have currently changed from passive to active. I need to tune the equipment by pressing multiple buttons many times because my equipment is pretty old. Also, I tune it based on human ear (myself) instead of using frequency meter or any automatic feature provided by the HU. It is a bit hard for me to do this job well.

By pressing button by button in daily basis, I believe I have tuned it in an acceptable manner. However, I start to query whether I did the right thing after reading many post in this Forum. Would you please help me to clarify anything I did wrong?

Equipment:

Front: 2 tweeter + 2 mid range (Crossover Point from Passive setting: 2,500Hz)

Rear: 2 tweeter + 2 mid range (Crossover Point from Passive setting: 4,000Hz)

Sub: 2 JL 10"

Total: ten speaker components

Based on the previous passive crossover setting retrieved from the data sheet, I start to move the frequency from 2,500 up or down in daily basis until I find the sound acceptable one day. I end up have the following setting on my Active Crossover.

Active Crossover Setting:

High: 2,200Hz

Mid-High: 2,500Hz

Mid-Low: 90Hz

Low: 90Hz

At the beginning, I just want to match the figures with the passive crossover point. However, the Active Crossover contains four figures that I can adjust. Afterward, I figure it out this is a matter of the slope and lines cross with each other.

1. Currently, the crossover point between midrange and tweeter is 2,350Hz. Am I setting the slope too steep? Too steep can cause Frequency Continous Problem, am I right?

2. There is almost no slope between Mid-range and Subwoofer based on my current setting. Are they interfered with each other?

3. I do the setting based on my Front Stage because 1) it is relately important than rear 2) my equipment only allows me to adjust it based on frequency overall but not PER speaker component basis.

4. Delay Time: That's even confuse me very much! According to my understanding, it's used to correct the sound delivery to the listener. However, he or she is not sitting in the middle of the car. Therefore the time delay setting should be based on speaker position. In my equipment, it only allows me to adjust the delay time in frequency basis. I don't know why.

I am using Alpine PRA-H400 as the Active Crossover. Please help or any suggestions would be appreciated.

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[zinda 10+ year member]

I'm not sure what Tweeters you are running but 2500Hz is really a low setting for even some of the best tweeters if you are going to be pushing any power through them. I would tend to think that 3kHz to 3.kHz is a more realistic setting for the Mid/Tweet crossover setting to start. The other thing you were mentioning was the time delay feature that works between the Frequency' what that is supposed to be doing is correlating the difference in the position between your Tweeter and Mids, that's why the coaxial speaker type was invented, this provides a more corrected alignment of the distances of the sound waves to your ears. It's not to be thought of as the time delay settings you now see in your Home Theater systems which are configuring each speaker box's distance from you. The car has a pretty much predetermined placing for your speakers and the idea of that placement is set up for you to get the sound from the speaker that is furthest away from you being on a more direct route to you ear. While the closer speaker will be heard more off axis and some of the sound is reflected, thus it will appear to have some time correction already set by placement alone. That's why rear fill is sometimes just a bad idea if you are shooting for sonic perfection in your car, most are looking for the loudest sound they can get out of the limited space that cars offer. That way using a rear fill is a good alternative to cutting custom holes and special stand-offs or remaking the entire door panel to accommodate the extra speakers needed to get a louder sound stage up front where it really should be. You can only get so much sound out of each speaker so the more you can fit up front the better. Of course this will just lead into more and more problems that you will encounter along the way. Not only from challenging installations but the tuning of a multi multi speaker configuration will become another issue in it's self. When tweeters are mounted both near the mids and far away from them at the same time you will not be able to set up your time delay to correct for this. I would mount all tweeters in clusters aimed in only slightly different angles to get wide sound coverage but can also be aligned properly with your sound processing unit. Minimize the reflecting sounds to help in creating a solid sound stage. I hope this made sense, it sounds like you have everything you need to get the job done, it really comes down to the installation to make it work. That's the trick with every set up though, you need to familiarize yourself with your equipment before doing any installation. You will find that doing right or close to right the first time will not only save time but also money and frustration you will encounter from a never ending install.

 

[xxyue188 10+ year member]

I'm not sure what Tweeters you are running but 2500Hz is really a low setting for even some of the best tweeters if you are going to be pushing any power through them. I would tend to think that 3kHz to 3.kHz is a more realistic setting for the Mid/Tweet crossover setting to start. The other thing you were mentioning was the time delay feature that works between the Frequency' what that is supposed to be doing is correlating the difference in the position between your Tweeter and Mids, that's why the coaxial speaker type was invented, this provides a more corrected alignment of the distances of the sound waves to your ears. It's not to be thought of as the time delay settings you now see in your Home Theater systems which are configuring each speaker box's distance from you. The car has a pretty much predetermined placing for your speakers and the idea of that placement is set up for you to get the sound from the speaker that is furthest away from you being on a more direct route to you ear. While the closer speaker will be heard more off axis and some of the sound is reflected, thus it will appear to have some time correction already set by placement alone. That's why rear fill is sometimes just a bad idea if you are shooting for sonic perfection in your car, most are looking for the loudest sound they can get out of the limited space that cars offer. That way using a rear fill is a good alternative to cutting custom holes and special stand-offs or remaking the entire door panel to accommodate the extra speakers needed to get a louder sound stage up front where it really should be. You can only get so much sound out of each speaker so the more you can fit up front the better. Of course this will just lead into more and more problems that you will encounter along the way. Not only from challenging installations but the tuning of a multi multi speaker configuration will become another issue in it's self. When tweeters are mounted both near the mids and far away from them at the same time you will not be able to set up your time delay to correct for this. I would mount all tweeters in clusters aimed in only slightly different angles to get wide sound coverage but can also be aligned properly with your sound processing unit. Minimize the reflecting sounds to help in creating a solid sound stage. I hope this made sense, it sounds like you have everything you need to get the job done, it really comes down to the installation to make it work. That's the trick with every set up though, you need to familiarize yourself with your equipment before doing any installation. You will find that doing right or close to right the first time will not only save time but also money and frustration you will encounter from a never ending install.

In your opinion, how can I tune the Time alignment if i have Rear Speakers in place?

Front Tweeter: Just in front of me

Front Mid-range: At the Door Panel

Rear Tweeter + Mid-range: Same place on top of the Rear Panel behind the Rear Glass

 

[calebkhill 10+ year member]

In your opinion, how can I tune the Time alignment if i have Rear Speakers in place?Front Tweeter: Just in front of me

Front Mid-range: At the Door Panel

Rear Tweeter + Mid-range: Same place on top of the Rear Panel behind the Rear Glass

Rear fill is usually not a good idea when trying too get good sq out of your system.

Read this:

GlassWolf's Pages

 

[zinda 10+ year member]

If you are dead set on having rear speakers, then the best advise I can give you is to remove the tweeters from the rear speakers. Then I would try and mount them up front near the other set, of course it would be best if all of your speakers were matched. At least made by the same company will really help a lot, they tend to use the same tweeters in their speaker lines. Meaning; for example - all the "Reference" series will use the same Mid and Tweets with the only changes being made to the larger sized drivers in that group. This way you can more easily tune your system, a lot of the speakers made have a way to remove the mids and tweets from the assembly so you can mount them separately, MB Quart was doing this 20 years ago so it's new to the market. I've already got out my sheet metal snips and cut the metal strip[s that were holding the cluster of useless squealing speakers to be ale to use the midbass with no interference. If you are not willing to remove them to reposition them, then I would simply disconnect the tweeters. This will keep the sound stage solidly up front and minimize reflected sounds. Also keeping the volume down to just a rear fill will be advisable. If you can move the tweeters , remember to use the crossover or buy a new ones or used ones that others have removed while switching to active crossover components (not recommended (my opinion)). If you can find some that have a selectable tweeter setting would be most desired, that way you can adjust the tweeters independently from the midbass, to some extent, without having to turn down the midbass at the same time. If you are using multiple tweeters this is the best way to control the overall sound in relation to the mids. That will get you in the ballpark and then you can more easily tune your set up. The more options you have to control the sound the better, to an extent. Too many and it becomes overwhelming and leads to more headaches and the dreaded never ending install/tuning that we all have encountered. If you do these things I believe that you will be able to control the system perfectly with your sound processor. The only thing you could do to make it better right off the bat to avoid going back and adding as I'm sure you will, is to add a second set of identical speakers up front to maximize the space available, and do it while you're performing the initial install to make it easier. Or do what I've learned to do with all of my installs, always run extra wires. I will run 2 extra sets of 16 gauge wires to the doors in case I encounter a problem with the 12ga I've planned on using, Or in case I decide to add more to the install. I will also run extra RCA's back to the trunk area for extra amps. That's what I'm using right now to audition a pile of amps I picked up. Also a large fuse distribution block with at least 4 fuses is mandatory along with a solid ground block, this all makes upgrades that much easier. Once again this is all up to you and how long you plan on keeping your car or that system. Your going to see new things come out almost daily and it's hard to resist the upgrades.

 

[xxyue188 10+ year member]

Thanks for all suggestions. I am going to disconnect the rear speakers next week and give you the result.

 

[calebkhill 10+ year member]

Thanks for all suggestions. I am going to disconnect the rear speakers next week and give you the result.

Please do. Also give it a day our so for you to adjust to the change. It may not sound right at first but after a day or so you'll get the feel of it.

Also, when disconnecting rear fill make sure everything is crossed over properly. Everything has to be crossed properly in order for it to sound right.

 

[keep_hope_alive Premium Member]

it would help if we know what slopes you could select for the crossover settings. we cannot discuss crossover points without knowing slopes.

manual says 18dB/oct for mid/high slopes and 24dB/oct for low slope.

time correction is in milli-seconds (ms) between 0-30ms in 0.3ms steps.

using time correction will help you achieve a sound stage, but as mentioned, the rear speakers will just destroy that sound stage.

when using time correction follow these steps.

1. measure distance (inches) of each left speaker to the left ear in normal driving position.

2. measure distance (inches) of each right speaker to the right ear in normal driving position.

3. adjust left speaker delays so arrival is equal by subtracting the difference and converting to time dividing measured distance (in inches) by 13.5in/msec (speed of sound).

4. adjust right speaker delays in a similar fashion.

now you have corrected the left speaker differences independently of the right speaker differences.

5. now you can center your sound stage by subtracting the difference between the furthest left speaker and the furthest right speaker.

6. finally, calculate the time associated with this distance and add it to all left speakers (assuming you sit in the left seat).

the owners manual will describe a similar process.

 

[xxyue188 10+ year member]

it would help if we know what slopes you could select for the crossover settings. we cannot discuss crossover points without knowing slopes.

18db/octive only for my crossover

 

[keep_hope_alive Premium Member]

however, you may find it sounds better to keep the passives and just run front/rear. that allows for more overall volume while also allowing for time alignment adjustment which can greatly improve the sound stage. you can eliminate rear tweeters from the mix and just run rear mids.

you can then follow the above steps for each of the four locations. then, you can further delay the rears until they blend into the background, keeping the front speakers as focus.

the reason this can work is that we don't use arrival time for localization of high frequencies above 3kHz. instead we use intensity. so the aiming of tweeters is more important than any delay you put on them.

 

[keep_hope_alive Premium Member]

the main benefit of running active is independent level control as well as time correction and flexible crossover slope/point. you also improve overall sound quality by eliminating passive impedance elements and passive phase shifts.

 

[zinda 10+ year member]

I'm not sure he has the ability to correct for distance with that unit. I think he has only the time correction for the difference of mounting points between the mid bass and tweeters. This is figured for component speakers mounting where the tweeters will be in higher placement giving them a shorter distance to your ears overall. But what you have stated here is really good information for any application that allows corrections to delays for distances per speaker!