help with 2 way active speaker setup

[rodneypierce 10+ year member]

then you need to verify proper polarity on every driver. having different left and right means you have polarity mixed up.
so reverse polarity on both - so you have the same focus but you blend well. right now, you dont know what actual phase is.

it is important that you use speaker wire that has identification for polarity, and that you are consistent with polarity. i use red and black heat shrink and/or electrical tape to label speaker wires for clear identification.

No... I know the polarity of each driver. They are all regular or standard polarity EXCEPT the drivers side midrange.

I went through and isolated each speaker after I did my TA, then switched each individual speakers polarity to see if it sounded better/centered the sound better, or if it scattered it again. If it sounded better, I left it, if it scattered it, I put the polarity back to normal. Then I switched the set polarity on each PAIR of speakers to test the same, if it didnt sound better, switched the PAIR back to how it was. They are all on standard ( + to +, - to -) polarity EXCEPT for the drivers side midrange. Its reversed.

 

[ngsm13 5,000+ posts]

time. They have a calculation that converts the distance in cm to ms. so i measured the distance to each speaker center from the center of the head rest in inches, converted it to CM, but then didnt know what to do from there.

Well, if your measuring tape has centimeters then just use that. Write down the distances for all four speakers.

Then use this equation:

CD5030 OWNER'S MANUAL - ECLIPSE by Fujitsu Ten

To find the t/a in milliseconds of your speaker, you take the furthest speaker, subtract the chosen speakers distance, then divide by 34. Obviously given this equation, you'll see tha the speaker with the furthest distance will have zero delay. Include your subwoofer, //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

The Dayton RS 180 may not be a great choice. They would need a tweeter that plays pretty low. I'd look for a mid that can at least get u to 3khz like the silver flutes.

Which is not a super big deal. It's definitely a good idea to shop around, and as mentioned DIYMA is a great source to read.

 

[rodneypierce 10+ year member]

To find the t/a in milliseconds of your speaker, you take the furthest speaker, subtract the chosen speakers distance, then divide by 34.

OK. Thats the part I didnt understand. So its for each speaker that your doing. (distance of furthest speaker minus the speaker your doing divided by 34).

 

[keep_hope_alive Premium Member]

No... I know the polarity of each driver. They are all regular or standard polarity EXCEPT the drivers side midrange.
I went through and isolated each speaker after I did my TA, then switched each individual speakers polarity to see if it sounded better/centered the sound better, or if it scattered it again. If it sounded better, I left it, if it scattered it, I put the polarity back to normal. Then I switched the set polarity on each PAIR of speakers to test the same, if it didnt sound better, switched the PAIR back to how it was. They are all on standard ( + to +, - to -) polarity EXCEPT for the drivers side midrange. Its reversed.

that tells me that your wiring is mixed up for that driver. you are doing the right thing using your ears to fix your wiring issues - but good wiring methods can save that step.

it doesn't change your phase issues due to your mixing of crossover slopes. with passive crossovers - the manufacturer handles any phase adjustments and polarity changes in the terminal labeling. with active, you need to understand how each adjustment changes driver phase, and how to account for that in your wiring. sometimes you must manually reverse polarity to realign acoustic phase relative to each driver. this is why processors have a phase adjustment - to make it easy without manually changing wiring.

you won't hear the difference of relative acoustic phase between tweeter and woofer by listening for "scattered sound". for that you must focus on how the speakers blend together - which your comments above (in conjunction with your crossover settings) tell me that is where your issues are.

T/A won't fix your issues, T/A can't fix acoustic phase problems, but it can make things worse. once you have proper acoustic phase on all drivers, T/A will simply shift the center of your sound stage - left/right, up/down, close/far. you may also notice more accurate midbass as it becomes centered in the sound stage.

 

[rodneypierce 10+ year member]

that tells me that your wiring is mixed up for that driver. you are doing the right thing using your ears to fix your wiring issues - but good wiring methods can save that step.
it doesn't change your phase issues due to your mixing of crossover slopes. with passive crossovers - the manufacturer handles any phase adjustments and polarity changes in the terminal labeling. with active, you need to understand how each adjustment changes driver phase, and how to account for that in your wiring. sometimes you must manually reverse polarity to realign acoustic phase relative to each driver. this is why processors have a phase adjustment - to make it easy without manually changing wiring.

you won't hear the difference of relative acoustic phase between tweeter and woofer by listening for "scattered sound". for that you must focus on how the speakers blend together - which your comments above (in conjunction with your crossover settings) tell me that is where your issues are.

T/A won't fix your issues, T/A can't fix acoustic phase problems, but it can make things worse. once you have proper acoustic phase on all drivers, T/A will simply shift the center of your sound stage - left/right, up/down, close/far. you may also notice more accurate midbass as it becomes centered in the sound stage.

Im sorry, but Im confused. I know for a fact the wiring on that driver was correct before i switched polarity. I used wire with a blue +++ on one lead, which went to the positive at the speaker, and the positive at the amp. All of them are marked, and Im very careful to make sure they get to the respective correct terminal.

 

[keep_hope_alive Premium Member]

i've felt certain before, then double checked/triple checked and realized i was wrong. it happens. i've also seen speakers with improper terminal labeling. or at the amp you make one final switch. wires with labels can be mixed up when the label is a few inches down the wire. i've even gone back and seen i put colored tape on the wrong wire.

point is, you're learning some of the quirks wth going active - things you need to think about that you haven't before.

also, it is possible you were hearing a ITD issue - depending on your source material. here are my steps

1. wire all speakers with proper polarity.

2. determine crossover slopes based on speaker parameters, response, power, and equipment capabilities.

3. change speaker polarity to account for crossover phase shift

4. T/A based on PLD to each respective ear from each voice coil center

5. listen - tweak crossovers points, tweak T/A. if i change slope, i adjust polarity accordingly.

 

[rodneypierce 10+ year member]

10-4. Ill check it out here tonight and make certain. I will also set the TA by measuring, instead of just trying it by ear first.

And by changing slope, you change polarity, your meaning if you run a 12 or 18db slope, to switch the polarity? As earlier I believe you said that makes them 180 out.

 

[keep_hope_alive Premium Member]

10-4. Ill check it out here tonight and make certain. I will also set the TA by measuring, instead of just trying it by ear first.
And by changing slope, you change polarity, your meaning if you run a 12 or 18db slope, to switch the polarity? As earlier I believe you said that makes them 180 out.

correct. either increase all crossover slopes to 24dB/oct (preferred) or reverse polarity on both woofers so they are opposite of what they are now. then adjust crossover slopes to introduce some overlap.

i have spent literally dozens of hours just listening to the effects of crossover slopes and polarity. the H701 is great for doing that, great for experimentation.

 

[ngsm13 5,000+ posts]

i've felt certain before, then double checked/triple checked and realized i was wrong. it happens. i've also seen speakers with improper terminal labeling. or at the amp you make one final switch. wires with labels can be mixed up when the label is a few inches down the wire. i've even gone back and seen i put colored tape on the wrong wire.
point is, you're learning some of the quirks wth going active - things you need to think about that you haven't before.

also, it is possible you were hearing a ITD issue - depending on your source material. here are my steps

1. wire all speakers with proper polarity.

2. determine crossover slopes based on speaker parameters, response, power, and equipment capabilities.

3. change speaker polarity to account for crossover phase shift

4. T/A based on PLD to each respective ear from each voice coil center

5. listen - tweak crossovers points, tweak T/A. if i change slope, i adjust polarity accordingly.

While regardless, I still agree with your process, I think that the idea of phase shift in an active setup is somewhat blown out of proportion. I think the real problem overall is the phase from an acoustic standpoint, not an electrical one. Phase problems are created by the different distances from the speakers. It’s normal for passive crossovers to be created with different slopes (and cut-off frequencies), from right to left to correct problems and staging. With active crossovers, phase shift is completely dependent on the circuit involved, whether it be IIR of FIR done onboard a DSP. It’s hard to get conclusive answers from manufacturer about the degree of phase shift which their devices incur. It’s important to note though, that the phase shift remains constand and does not change with respect to frequency, an effect of not having the impedance curve of the driver to deal with.

In the end, is it really a huge deal? I mean, acoustically the inside of a car is a nightmare. In a car we have to consider reflections, resonances, frequency, phase, responses between all of the drivers. I would say there are bigger problems for signal purity than the phase changes cause by active filters.

10-4. Ill check it out here tonight and make certain. I will also set the TA by measuring, instead of just trying it by ear first.
And by changing slope, you change polarity, your meaning if you run a 12 or 18db slope, to switch the polarity? As earlier I believe you said that makes them 180 out.

See above for a little information from my standpoint. Regardless, the process he listed is the proper order in which to address things.

 

[keep_hope_alive Premium Member]

In the end, is it really a huge deal? I mean, acoustically the inside of a car is a nightmare. In a car we have to consider reflections, resonances, frequency, phase, responses between all of the drivers. I would say there are bigger problems for signal purity than the phase changes cause by active filters.

See above for a little information from my standpoint. Regardless, the process he listed is the proper order in which to address things.

yes, it is very important to get acoustic phase correct at crossover points. polarity affects acoustic phase, but we know polarity is relative. phase issues at crossover points will make a good system sound like poop. is it the only challenge? certainly not. is it important? yes. normally, it is not an issue since very few systems ever run into the specific circumstances required for it to be an issue - but when it is a problem, it's noticable and important. of course, the vehicle itself plays a role - as does speaker placement.

you can test this yourself. take your front stage woofers and reverse polarity on them - leaving everything else as-is. see for yourself if you think it's a big deal to have woofers out of acoustic phase with tweeters and subs.

//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif