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Ron E

Active crossover with 2x4 MiniDSPs

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I am hoping I can get some assistance with getting my setup converted to active crossovers.

Here is my current front 3 setup:

JBL 2360A horns

EV DH1a drivers

1/4 Pie bass bins

I have 2 Yamaha P2500 amps for the bass bins, and "T" chip amps for the JBL 2360a horns, and 3 MiniDSP 2x4s unbalanced. We are currently using the old La Scala AA crossovers with the wire going to tap #4 on the Klipsch T2A autoformer moved to tap #3.

I am running these as a 2 way. I have been looking at the MiniDSP downloads and I am not sure which one to get... I am assuming the 2 way advanced... ?

To get this started would I make all the settings in the MiniDSP the same as the stock AA crossovers and then go from there... If so what would the settings be?

I also have a Beringer FB for EQ of the 2 Danley DTS-10 subs (I have a Denon 4520 too).

tia,

Ron

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If you are using one minidsp 2x4 kit per speaker you can do the 2 way advanced or stereo 3/4 way which will also work for a 2 way. If I was only going with a 2 way setup I would use one minidsp box for the front left and right speaker as it has two inputs and four outputs plus everything can be programmed on the one box. To start with settings I would just choose a 400hz crossover and use the LR 24Db slope. You will have to match driver levels by ear and adjust the volume of each driver using the gains on the amp leave the minidsp output at 0. The unit also allows time alignment and custom biquad crossover settings. All of the advanced features are pretty useless without some sort of measurement setup. Lastly using the unbalanced versions of the minidsp might not provide enough voltage to fully drive your amps. In my setup I use the 2x8 minidsp and will never go back to passive crossovers in my front speakers as I love the ability to be able to tweak setting on the fly.

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If you are using one minidsp 2x4 kit per speaker you can do the 2 way advanced or stereo 3/4 way which will also work for a 2 way. If I was only going with a 2 way setup I would use one minidsp box for the front left and right speaker as it has two inputs and four outputs plus everything can be programmed on the one box. To start with settings I would just choose a 400hz crossover and use the LR 24Db slope. You will have to match driver levels by ear and adjust the volume of each driver using the gains on the amp leave the minidsp output at 0. The unit also allows time alignment and custom biquad crossover settings. All of the advanced features are pretty useless without some sort of measurement setup. Lastly using the unbalanced versions of the minidsp might not provide enough voltage to fully drive your amps. In my setup I use the 2x8 minidsp and will never go back to passive crossovers in my front speakers as I love the ability to be able to tweak setting on the fly.

Thanks. So I can use 1 MiniDSP for the left and right and another for the center, correct? To match the driver levels... What do I play? Would it be a test tone or music? I have a MiniDSP UM1K mic for measuring. I don't think I need to fully drive the amps as the Pro amps will be only driving the Bass bins, and I can't imagine ever using more than a few wpc even at reference levels. The JBL horns should be using way less than 1 wpc even at reference levels too, I believe. Feel free to correct me if I am wrong. Should I just use the BFD for the subs, or the MiniDSP, or could both be used?

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Going active Bi-amp a few weeks back, i will never go back to anything less.

I have proven i can pizz off a neighbor without the amp(s) even warming up.

Good luck in your project ellis, wish i could help however i know nothing about DSPs.

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Yes you can use one for the front left and right and one for the center. As far as level matching I also have a minidsp umik 1 I use for measurements. The first thing I would do is run frequency sweeps of the speakers using rew. Place the mic 3-6 feet from the speakers at ear level. Look at the graphs and if below and above 400hz is  is not even (except at the crossover point as this requires time alignment)then adjust the gains on either the woofer or tweeter amp until they are. With as efficient as your speakers are the gains should not have to be turned up past 1/4 of the way on the amp for the top and maybe half way on the bottom. Remember the top end is more efficient than the bottom. I'm still getting mine all setup as I'm using a 4 way per left and right front. Also the frequency sweeps will help to get the drivers time aligned. You want the frequency to be flat at the crossover. To do this adjust the delay on the top end output as the bottom end has the longer horn. I would start with a few milliseconds and work my way up. Also the 4th order LR sums flat at the crossover so you will not have to do anything with the phase of the drivers. The best part about going active is you can make all the changes you want on the fly. Don't be afraid to try different slopes either as you may prefer one over the other, but depending on the one you choose could cause the drivers to become out of phase.

Edited by shepjk01

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Is this correct? crossover_zps6784c29d.jpg

400 goes in the low pass? What goes in the hi-pass?

Edited by ellisr63

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Forgot the part about the t chip amp. If it does not have a volume control you will have to use the volume setting in the mini dsp to lower the top end which is fine. I would start with -7 as your top horns are probably about that much more efficient than the bottoms. The minidsp has a parametric eq built in so you use that for the fronts and center.

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Forgot the part about the t chip amp. If it does not have a volume control you will have to use the volume setting in the mini dsp to lower the top end which is fine. I would start with -7 as your top horns are probably about that much more efficient than the bottoms. The minidsp has a parametric eq built in so you use that for the fronts and center.

The T chip amps have a volume control but no balance control so both will be identical. I believe the horns with the EV drivers are rated at 112db with 1 watt. Edited by ellisr63

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 The high pass is the cutoff at the bottom end say 55hz or the bottom frequency at which the quarter pie loads the driver.

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Since the t chip amps have volume controls use those to adjust the top end and leave the output of the minidsp at 0.

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Thanks, I just ordered the rest of the cables I need to get the bi-amp completed. If the cables are here by Saturday morning I will try this on the weekend. :) Can't wait to hear all the Yamaha Pro amps on the 1/4 pies, and the "T" chip amps on the JBL horns. I hope it improves the sound even more over the "AA" Networks.

This is what I have the MiniDSP set to for starters...

crossover2_zps6c16929d.png

Will this be ok... Or should I be crossing over at 500hz? When I look at the specs for the EV DH1a it says "500-20,000 Hz (essentially flat 500-5,000Hz with 6-dB-per-octave roll off to 20,000 Hz, rapid roll off beyond)".

Edited by ellisr63

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You can use 500hz also it just depends where the quarter pie rolls off at on the high end. That's the nice thing about going active you can make all the adjusts and test in real time.

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What would be helpful is to get a FR plot of the lascalas as they are now wiht the passive networks............so you have a reference measurment of the speaker output containing all the drivers.

 

You can aim for a similar output with the active system.  It will be a big help in balancing the drivers outputs.

 

 

Edit:  Not sure why I thought you had lascalas.........after re-reading first post that was a mistake obviously.  Still,  a reference measurement of the system output as it is today will help you big time as trying to tune and active system by ear with no reference plot is a sure way to get lost.

 

.

Edited by mark1101
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What would be helpful is to get a FR plot of the lascalas as they are now wiht the passive networks............so you have a reference measurment of the speaker output containing all the drivers.

 

You can aim for a similar output with the active system.  It will be a big help in balancing the drivers outputs.

 

 

Edit:  Not sure why I thought you had lascalas.........after re-reading first post that was a mistake obviously.  Still,  a reference measurement of the system output as it is today will help you big time as trying to tune and active system by ear with no reference plot is a sure way to get lost.

 

.

I started out with 3 La Scalas... :) Wouldn't setting the active crossover to 400hz, LR24db/oct have me the same as the AA Networks? If it is levels we are talking... How do I match the levels of the JBLs with the 1/4 pies... Do I play a certain frequency through the speaker and shoot for a certain level or use use music? I am hoping I can get a friend to come over and help me do the measurements this weekend.

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What would be helpful is to get a FR plot of the lascalas as they are now wiht the passive networks............so you have a reference measurment of the speaker output containing all the drivers.

 

You can aim for a similar output with the active system.  It will be a big help in balancing the drivers outputs.

 

 

Edit:  Not sure why I thought you had lascalas.........after re-reading first post that was a mistake obviously.  Still,  a reference measurement of the system output as it is today will help you big time as trying to tune and active system by ear with no reference plot is a sure way to get lost.

 

.

I started out with 3 La Scalas... :) Wouldn't setting the active crossover to 400hz, LR24db/oct have me the same as the AA Networks? If it is levels we are talking... How do I match the levels of the JBLs with the 1/4 pies... Do I play a certain frequency through the speaker and shoot for a certain level or use use music? I am hoping I can get a friend to come over and help me do the measurements this weekend.

 

 

It depends what your goals are for your active system.  When I think of someone going to an active system, I picture them trying to replicate what they already have in their passive system.  At least as a baseline to get things ballparked.  I would use Pink noise and get a baseline FR plot before moving to the active system.  Once the active is setup, you can try to replicate (or come close) to what you previously had so your system should sound similar.  Then you can gradually make small adjustements over time as you listen to music until you finally stop fooling with things.

 

An AA does not use 24db slopes.  I would ask Dean or another network person about this.  I think the AA uses different slopes on each crossover point.

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What would be helpful is to get a FR plot of the lascalas as they are now wiht the passive networks............so you have a reference measurment of the speaker output containing all the drivers.

 

You can aim for a similar output with the active system.  It will be a big help in balancing the drivers outputs.

 

 

Edit:  Not sure why I thought you had lascalas.........after re-reading first post that was a mistake obviously.  Still,  a reference measurement of the system output as it is today will help you big time as trying to tune and active system by ear with no reference plot is a sure way to get lost.

 

.

I started out with 3 La Scalas... :) Wouldn't setting the active crossover to 400hz, LR24db/oct have me the same as the AA Networks? If it is levels we are talking... How do I match the levels of the JBLs with the 1/4 pies... Do I play a certain frequency through the speaker and shoot for a certain level or use use music? I am hoping I can get a friend to come over and help me do the measurements this weekend.

 

It depends what your goals are for your active system.  When I think of someone going to an active system, I picture them trying to replicate what they already have in their passive system.  At least as a baseline to get things ballparked.  I would use Pink noise and get a baseline FR plot before moving to the active system.  Once the active is setup, you can try to replicate (or come close) to what you previously had so your system should sound similar.  Then you can gradually make small adjustements over time as you listen to music until you finally stop fooling with things.

 

An AA does not use 24db slopes.  I would ask Dean or another network person about this.  I think the AA uses different slopes on each crossover point.

We have been using the AA Networks just to be able to use the setup until the Active was ready to install. We are not trying to get it the same as the AA (only for a starting point), but to get the whole active setup to sound its best. We have no idea how it will sound compared to the AA Networks. I am assuming (and hoping) that the sound will only get much better with the Active setup.

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You should notice it to be clearer.  I'm not sure what you mean by better.  The only big difference should be time alignment unless you are moving to different amps.

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You should notice it to be clearer.  I'm not sure what you mean by better.  The only big difference should be time alignment unless you are moving to different amps.

When we built the setup we had a AA network laying around and decided to use it temporarily (even though the crossover points may not be what is needed)... It sounds good (after Audyessy) using the Denon 4520 for amplification. The goal was to get a proper crossover setup and go bi-amp with new amps too. I now have the T chip amps (for the JBL 2360a horns), and the Yamaha P2500s amps (for the 1/4 pies)... So no we are ready (I think) to complete the process of getting the setup to sound as good as it can with what I have to work with. Does this make more sense now? Basically I am trying to get the setup running active and sound as good as it is capable of with my setup.

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The AA uses a very shallow slopes I think 6 db on the woofer and 12 on the mid could be wrong on the mid. I would take a frequency response measure as stated with the AA in and use it as a baseline. Note the position of the volume on your denon and also of the mic. Now when you go active place the mic in the same position and the denon on the same volume. Adjusts the gains on your amps to match up to the other graph db wise. This will get you a baseline.

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