Hello!
I recently built my first pair of DIY speakers!
A 86 litres bass-reflex cabinet with the following drivers:
low: eminence delta 15 lfa (sensitivity: 96db)
mid: electro-voice 1823M (sensitivity: 118db)
high: JBL 2402 (sensitivity 110db)
The cabinet is inspired by a document called 'cabinet recommendations for eminence delta 15 lfa', found on the eminence website.
I bought two DAP cross-overs ( DAP PCX-4 Passive Crossovers | Geluid, Dj-gear, Speakers, Mixers, CD-spelers, Licht - Pioneer, JBL, Sennheiser - SoundXplosion.nl )
the cross-over points at are 800hz and 6000hz
The speakers sound amazing and are a big step forward regarding my older (but good) akai speakers.
Here some pictures:
(need to paint the bass-reflex ports! Movies are projected on the white wall. The little lcd is for News only
)
If the pictures don't show up, click this link: https://picasaweb.google.com/113671106596171841921/Luidsprekers# !
Now here is my problem. I recently did a SPL test, and it turned out that the curve isn't straight at all.
The mids are too loud, and there is a severe peak at 800hz (that makes the sound a bit like it is in a church)
I tried fixing this with an equalizer, but that didn't work very good. Besides, there is no 800hz frequency meter at the equalizer..
So, I want to fix this. What is the best solution?
Active filtering and bi-amping (mids and highs together/ lows separated)
Or a new DIY passive cross-over? The problem is that I don't know how to make a cross-over.
Could someone help me?
Thank you very much in advance!!!
I recently built my first pair of DIY speakers!
A 86 litres bass-reflex cabinet with the following drivers:
low: eminence delta 15 lfa (sensitivity: 96db)
mid: electro-voice 1823M (sensitivity: 118db)
high: JBL 2402 (sensitivity 110db)
The cabinet is inspired by a document called 'cabinet recommendations for eminence delta 15 lfa', found on the eminence website.
I bought two DAP cross-overs ( DAP PCX-4 Passive Crossovers | Geluid, Dj-gear, Speakers, Mixers, CD-spelers, Licht - Pioneer, JBL, Sennheiser - SoundXplosion.nl )
the cross-over points at are 800hz and 6000hz
The speakers sound amazing and are a big step forward regarding my older (but good) akai speakers.
Here some pictures:
(need to paint the bass-reflex ports! Movies are projected on the white wall. The little lcd is for News only
)If the pictures don't show up, click this link: https://picasaweb.google.com/113671106596171841921/Luidsprekers# !
Now here is my problem. I recently did a SPL test, and it turned out that the curve isn't straight at all.
The mids are too loud, and there is a severe peak at 800hz (that makes the sound a bit like it is in a church)
I tried fixing this with an equalizer, but that didn't work very good. Besides, there is no 800hz frequency meter at the equalizer..
So, I want to fix this. What is the best solution?
Active filtering and bi-amping (mids and highs together/ lows separated)
Or a new DIY passive cross-over? The problem is that I don't know how to make a cross-over.
Could someone help me?
Thank you very much in advance!!!
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Thank you for your answer.
This would mean that I need two active cross-over and 3 stereo amps, right?
Is that cheaper than a passive cross-over?
I would consider this investment, if it works good and finetuning is easy and effective.
Is there a big quality difference in active cross-overs?
What trade mark do you recommend regarding price/quality?
Thank you in advance!
This would mean that I need two active cross-over and 3 stereo amps, right?
Is that cheaper than a passive cross-over?
I would consider this investment, if it works good and finetuning is easy and effective.
Is there a big quality difference in active cross-overs?
What trade mark do you recommend regarding price/quality?
Thank you in advance!
Some attenuation on the midrange will probably help (do a search on Lpad's) You can place it after your crossover. The tweeter probably needs some as well.
If you don't want to go fully active you could get a second amp and still use passive on the mid/tweeter and an active crossover for the bass to mid/treble. This should help with the biggest efficiency difference you have with the 15" drivers only being 96db (it feels wrong saying only there). Taking into account baffle step losses as well you are probably around 20db down compared to your tweeter level and a staggering 28db compared to the midrange!
I'm assuming your off the shelf crossover has no attenuation in it whatsoever.
You would only need a relatively small amp for the mid/tweeter due to the insanely high efficiency of the drivers.
So for a quick (and cheap) fix for the inbalance (without thinking about fixing all all of the inadequacies of an off the shelf crossover) some lpad's on the midrange especially and also the tweeter would probably make a big difference to the overall tonal balance.
edit: I just checked the datasheet for the mid, the spl levels are 1M at 90W input!! not comparing apples with apples... I don't know the formula to translate that back to 1W / 1M to get something comparable to the eminence spec...
edit2: also I don't know which horn you are using with the mid, but both the spl graphs in the datasheet I would not want to cross it much higher than 3000Hz...
Tony.
If you don't want to go fully active you could get a second amp and still use passive on the mid/tweeter and an active crossover for the bass to mid/treble. This should help with the biggest efficiency difference you have with the 15" drivers only being 96db (it feels wrong saying only there). Taking into account baffle step losses as well you are probably around 20db down compared to your tweeter level and a staggering 28db compared to the midrange!
I'm assuming your off the shelf crossover has no attenuation in it whatsoever.
You would only need a relatively small amp for the mid/tweeter due to the insanely high efficiency of the drivers.
So for a quick (and cheap) fix for the inbalance (without thinking about fixing all all of the inadequacies of an off the shelf crossover) some lpad's on the midrange especially and also the tweeter would probably make a big difference to the overall tonal balance.
edit: I just checked the datasheet for the mid, the spl levels are 1M at 90W input!! not comparing apples with apples... I don't know the formula to translate that back to 1W / 1M to get something comparable to the eminence spec...
edit2: also I don't know which horn you are using with the mid, but both the spl graphs in the datasheet I would not want to cross it much higher than 3000Hz...
Tony.
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Thank you very much for the answers!
I appreciate this!
Indeed, the midrange falls off after 3000hz! I hadn't seen that before! Thank you for noticing.
It was a bit stupid buying cheap off the shelf X-overs, while the drivers costed a lot more, even used..
It seems that the X-overs ruin the capabilities of the drivers.
I'll try both options:
- active filtering (in a prototype setup) --> I found a program on internet called "foobar2000" with an active cross-over plug-in which converts the stereo, surround and center/sub outputs of my 7.1 soundcard into 3 seperate stereo channels, each providing the signal of a defined frequency-band. It is possible to configure the gain of each band, and of course to define where each band starts and stops.
A time ago, I made a 6 channel amplifier for a surround equipment (that I don't use anymore). It's not very high end, but good. It will give an idea I guess. I'll use 4 channels of this amplifier (for the mids and the highs). And my marantz for the low frequencies (because of its good damping factor).
Before I connect everything, two more questions:
a. can I damage the diaphragma of the electrovoices and the JBL's? Or can't this happen because the frequencies are adapted to the drivers?
b. Can I bridge the passive X-over by connecting the drivers directly to the amps? Or is this dangerous and shoud I disconnect each driver from the passive X-over?
- passive filtering: when I don't find an active X-over and one or two more amps for a reasonable price, I'll stay with the Lpads to attenuate the enthousiastic mid and high-drivers. But this is step 2...
Thank you in advance!
I appreciate this!
Indeed, the midrange falls off after 3000hz! I hadn't seen that before! Thank you for noticing.
It was a bit stupid buying cheap off the shelf X-overs, while the drivers costed a lot more, even used..
It seems that the X-overs ruin the capabilities of the drivers.
I'll try both options:
- active filtering (in a prototype setup) --> I found a program on internet called "foobar2000" with an active cross-over plug-in which converts the stereo, surround and center/sub outputs of my 7.1 soundcard into 3 seperate stereo channels, each providing the signal of a defined frequency-band. It is possible to configure the gain of each band, and of course to define where each band starts and stops.
A time ago, I made a 6 channel amplifier for a surround equipment (that I don't use anymore). It's not very high end, but good. It will give an idea I guess. I'll use 4 channels of this amplifier (for the mids and the highs). And my marantz for the low frequencies (because of its good damping factor).
Before I connect everything, two more questions:
a. can I damage the diaphragma of the electrovoices and the JBL's? Or can't this happen because the frequencies are adapted to the drivers?
b. Can I bridge the passive X-over by connecting the drivers directly to the amps? Or is this dangerous and shoud I disconnect each driver from the passive X-over?
- passive filtering: when I don't find an active X-over and one or two more amps for a reasonable price, I'll stay with the Lpads to attenuate the enthousiastic mid and high-drivers. But this is step 2...
Thank you in advance!
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Yes you can damage the mid and high if you set their high pass filter frequency too low or too shallow slope. See if you can find datasheets for them and look up their resonance frequency (Fs). Keep the filter frequency at least double this.
You should be disconnect the crossovers as you may get some signal passthrough the wrong way.
Ensure that the amp you will use for mid and high does not have any turn on thump or cone movement.
You should be disconnect the crossovers as you may get some signal passthrough the wrong way.
Ensure that the amp you will use for mid and high does not have any turn on thump or cone movement.
I tried the active X-over setup.
Wow, that's a difference!
I tried it with one of the speakers, so I could only test mono.
But now I know looking for an active X-over is worth it!
I don't know if I have to go active for the 3 speakers. Does it makes a big difference or could I also split low and mid-high with an active filter (passive filtering mid and high) without a lot of qualityloss?
Thanks in advance!
Wow, that's a difference!
I tried it with one of the speakers, so I could only test mono.
But now I know looking for an active X-over is worth it!
I don't know if I have to go active for the 3 speakers. Does it makes a big difference or could I also split low and mid-high with an active filter (passive filtering mid and high) without a lot of qualityloss?
Thanks in advance!
Looking for an active X-over to experiment with, I found a used 'Inkel DIV 23' active cross-over.
The cross-over has XLR-connections, but the input of my amps are rca.. Is there a proper way to connect rca output to XLR input?
While experimenting with the active x-over (on computer with the program foobar2000), I connected all the drivers (15 inch woofer, electrovice mid, jbl high) with the (budget) DIY amp. The woofer didn't sound good (muddy), but the mids/highs sounded acceptable.
So I connected the 15 inch woofer with the marantz (and the mid/high with the budget DIY amp). That was better! The woofer sounded dry and defined and the mids/highs sounded very acceptable.
Will there be a big difference in detail if I connect the mids/highs also to an amp like the Marantz? Or is there no such difference in the higher frequencies as in the lower frequencies and could I stay wit the DIY amp for the mids and highs?
Thanks in advance!
The cross-over has XLR-connections, but the input of my amps are rca.. Is there a proper way to connect rca output to XLR input?
While experimenting with the active x-over (on computer with the program foobar2000), I connected all the drivers (15 inch woofer, electrovice mid, jbl high) with the (budget) DIY amp. The woofer didn't sound good (muddy), but the mids/highs sounded acceptable.
So I connected the 15 inch woofer with the marantz (and the mid/high with the budget DIY amp). That was better! The woofer sounded dry and defined and the mids/highs sounded very acceptable.
Will there be a big difference in detail if I connect the mids/highs also to an amp like the Marantz? Or is there no such difference in the higher frequencies as in the lower frequencies and could I stay wit the DIY amp for the mids and highs?
Thanks in advance!
I also came across this active X-over with jack 6.3mm connections:
http://www.unika.com.tw/archive/products_detail/cf80e29ece21eff9faa0715892515423.jpg
http://www.unika.com.tw/archive/products_detail/f692b6e38f19ee0ac5dd401edaa34012.jpg
Is it easier to connect rca to jack?
http://www.unika.com.tw/archive/products_detail/cf80e29ece21eff9faa0715892515423.jpg
http://www.unika.com.tw/archive/products_detail/f692b6e38f19ee0ac5dd401edaa34012.jpg
Is it easier to connect rca to jack?
Always, always use a DC blocking cap even with an active crossover for the mid and tweeter. Maybe, some mids are robust enough. Depends on what they cost and if you are willing to take the risk. A good $20 poly cap is a lot cheaper that a tweeter.
Be sure the gain of all the amps is the same. That goes for the sub amps too. Other wise the balance will change when you change volume.
A couple other advantages of active: It is a lot easier to add extra filters to help the bass along in your room, BSC and of course, dealing with the driver impedance is then the amp's problem, not the crossover. Active usually allows 24dB slopes, which I far prefer for a sub as I can raise the crossover to as high as 80 Hz and still not localize the sub. (If I have a plate amp, I add in it's crossover for a very steep cutoff) Using a typical "sub crossover" I have to drop to about 60 Hz.
There are plenty of adapters for RCA to phone or RCA to XLR. Piece of cake. I just make my own cables as I like to keep things short and tidy. I use a cheap Bheringer in one of my systems. I really need to upgrade to a DIY one of these days. Most any discount music supply store has the adapters cheap.
I was amazed the difference in sound when I replaced a pair of plate amps with a used Parasound on the subs. It should not have made a difference, but it was striking.
Be sure the gain of all the amps is the same. That goes for the sub amps too. Other wise the balance will change when you change volume.
A couple other advantages of active: It is a lot easier to add extra filters to help the bass along in your room, BSC and of course, dealing with the driver impedance is then the amp's problem, not the crossover. Active usually allows 24dB slopes, which I far prefer for a sub as I can raise the crossover to as high as 80 Hz and still not localize the sub. (If I have a plate amp, I add in it's crossover for a very steep cutoff) Using a typical "sub crossover" I have to drop to about 60 Hz.
There are plenty of adapters for RCA to phone or RCA to XLR. Piece of cake. I just make my own cables as I like to keep things short and tidy. I use a cheap Bheringer in one of my systems. I really need to upgrade to a DIY one of these days. Most any discount music supply store has the adapters cheap.
I was amazed the difference in sound when I replaced a pair of plate amps with a used Parasound on the subs. It should not have made a difference, but it was striking.
Moved to multiway. I hadn't even noticed! Good tip on the gain of the amps, something I had not thought about, and would have had me scratching my head when I finally get my active crossover done for my "subs"!
The gain on the two amps I was planning to use is quite different, I figured I'd just attenuate the higher gain one (as I can't easily change it due to a very compact p2p construction that makes changing the gain resistors almost impossible. I might need to make the BA3 sooner than I thought...
Tony.
The gain on the two amps I was planning to use is quite different, I figured I'd just attenuate the higher gain one (as I can't easily change it due to a very compact p2p construction that makes changing the gain resistors almost impossible. I might need to make the BA3 sooner than I thought...
Tony.
Thank you for the tip!
So those DC blocking caps, how does they work, what's their deal in the cross-over?
Is there a formula to calculate their value regarding the cut-off frequency of each driver? I'm sorry, this is defenitely a 'noob' question, but I'm quiete new in cross-over networks..
And what do you mean with 'sub', tvrgeek? Do you mean subwoofer or just the woofer (eminence delta 15lfa in my case)?
So those DC blocking caps, how does they work, what's their deal in the cross-over?
Is there a formula to calculate their value regarding the cut-off frequency of each driver? I'm sorry, this is defenitely a 'noob' question, but I'm quiete new in cross-over networks..
And what do you mean with 'sub', tvrgeek? Do you mean subwoofer or just the woofer (eminence delta 15lfa in my case)?
basically a cap in series with the mid and tweeter will protect the speaker agains DC (should the amp develop a fault, or pass through any DC from the source. The cap will be a first order crossover, so needs to be chosen to roll off below the active crossover frequency.
You will need to know the impedance of the speakers to choose properly. (or you could just go bigger). here is an online calculator to help Crossover Design Chart and Inductance vs. Frequency Calculator(Low-pass)
I'm not sure how far below the active crossover frequency you would want to put the passive crossover point, to avoid having much effect on your active acoustic slope., I'll do some spice simulations later today to get an idea
edit: I did a quick sim using a 6 ohm resistor as the load. note that the lower the impedance the bigger the cap you will need. note that the sim is overly simplistic but gives an idea of how the cap will affect response. I'd be tempted to say 100uF for the tweeter, but that seems a bit extreme, perhaps tvrgeek can chime in as I have no practical experience in doing this (having only done passive crossovers).
see attached pic.
Tony.,
You will need to know the impedance of the speakers to choose properly. (or you could just go bigger). here is an online calculator to help Crossover Design Chart and Inductance vs. Frequency Calculator(Low-pass)
I'm not sure how far below the active crossover frequency you would want to put the passive crossover point, to avoid having much effect on your active acoustic slope., I'll do some spice simulations later today to get an idea
edit: I did a quick sim using a 6 ohm resistor as the load. note that the lower the impedance the bigger the cap you will need. note that the sim is overly simplistic but gives an idea of how the cap will affect response. I'd be tempted to say 100uF for the tweeter, but that seems a bit extreme, perhaps tvrgeek can chime in as I have no practical experience in doing this (having only done passive crossovers).
see attached pic.
Tony.,
Attachments
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Here is a comparison with different impedance loads. A speaker presents a complex load that a resistor cannot simulate, however the graph shows the importance of knowing roughly the impedance of the driver. If you measure the dc resistance of the voice coil that should give you the worst case impedance, size based on that and you should be ok.
Tony.
Tony.
Attachments
If you really want to do this right, you need to measure. A mic, a soundcard and some free software will get you there. Oh, and some help on this forum.
For really finding what works, the Berhinger DCX2496 digital crossover is great. You can keep it (and upgrade it) or move on to a passive crossover as you see fit.
You need to measure first, for sure. Very nice looking set-up, BTW.
For really finding what works, the Berhinger DCX2496 digital crossover is great. You can keep it (and upgrade it) or move on to a passive crossover as you see fit.
You need to measure first, for sure. Very nice looking set-up, BTW.
Ok, I think I understand.
So for the JBL tweeter (2402), I found a DC impedance of 6.25ohm on the spec sheet.
If I would do an active crossover at 4500hz (this sounded quiete good when I tested) and the minimum crossover frequency of the jbl 2402 tweeter is 2500hz (spec sheet), I thought of a DC blocking cap that cuts off at 3500hz.
The calculator (first order cross-over at 6db/octave) gives me a result of a cap with the following value: 7.268571428571429 µf
Could that be correct? Or do I need a second/third/... order crossover?
So, I have to find out the DC impedance of the midrange driver too and to calculate the value of this cap too, isn't it?
Is there a difference when putting the cap in series with the driver if I put it on the + or the - of the driver?
Yet another question: are digital cross-over much better then analog cross-overs? I found some analoge X-overs for a reasonable price, but those aren't as advances as the digital behringer suggested...
So for the JBL tweeter (2402), I found a DC impedance of 6.25ohm on the spec sheet.
If I would do an active crossover at 4500hz (this sounded quiete good when I tested) and the minimum crossover frequency of the jbl 2402 tweeter is 2500hz (spec sheet), I thought of a DC blocking cap that cuts off at 3500hz.
The calculator (first order cross-over at 6db/octave) gives me a result of a cap with the following value: 7.268571428571429 µf
Could that be correct? Or do I need a second/third/... order crossover?
So, I have to find out the DC impedance of the midrange driver too and to calculate the value of this cap too, isn't it?
Is there a difference when putting the cap in series with the driver if I put it on the + or the - of the driver?
Yet another question: are digital cross-over much better then analog cross-overs? I found some analoge X-overs for a reasonable price, but those aren't as advances as the digital behringer suggested...
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