Splitter for analog XO mids/highs, and active digital XO on sub and midbass?
Hi,
I am building these nice stereo hornspeakers. I have been using a minidsp 4x10HD digital crossover device with good results. It has been helpful to find the right crossover points. The Minidsp device is digital and degrades the signal and with horns you can really hear it. It also adds hum to my tube amps, forcing me to use an anti-hum isolation transformer that also degrades the signal. I would like to avoid it all together, but the JBL 2225H 15" midbass and the Eminence LAB12 subwoofer works best with an active crossover, so why not use it for them. I doubt I can hear much difference on bass anyway.
I have borrowed a crossover design from Klipsch for the horns that I am pleased with so far.
Situation:
LP-player(unbalanced)/Computer with LYNX L22 sound card (balanced or unbalanced) -> splitter of unknown kind->
-> Analog 2nd XO for mid horns and horn tweeter -> 2A3 tube amplifier
-> Minidsp+DIRAC device subwoofer and midbass-> B1 Buffer preamp+DIY F5 amplifier for midbass, and 800W PA amplifier for subwoofer.
Question:
What kind of splitter should I use??
I want to use is a passive splitter, but I read a Y-cable would lead to impedance mismatch and ground issues. I could use an active splitter, but I would like to avoid it. A good active splitter without added noise is expensive. The Behringer ULTRALINK PRO
MX882 is in my price range but probably noisy. I have not had any luck finding a schematic for an unbalanced active splitter yet. I was hoping I could build a passive splitter with Lundahl transformer, but some of the comments (read below) suggests I should not.
I have done (part) of my homework and found these comments:
On line splitters:
"RONALD DUMSFIELD: Provided that both input impedances are sufficiently high and more or less equal if you split a signal into two there will be no loss of signal quality but the strength will be halved. Resulting in a 3dB loss. So if you keep on doing it eventually it's going to effect your S/N ratio. The convention is you can safely split up to 3 times provided you have sufficient gain available. Which you probably have. Extra cable length may also lead to noise if you have a ground issue.
Unbalanced line level splitters (and combiners) are rare. You can see the problem. Connecting together the grounds on several consumer grade appliances spread over a wide area is almost certain to lead to ground loop issues. That is why professionals use something called a distribution amplifier for this task. It not only splits (or combines) a signal it also converts unbalanced to balanced and provide a small amp per channel to adjust the gain. You can get cheap ones from the likes of Berhinger and ART or top of the range from Drawmer and Radial.
MUSIC Group
Drawmer Electronics - DA6
I still think that if the OP has the cash he would do best with a basic audio interface which is designed for the task in hand. And many other useful functions. You can get a 2 in 2 out unit with headphone from around $150. better would be 2 in and 4 out which starts at ~$200. If that's too steep then stick with a simple Y lead for now and hope you don't get a ground loop."
A comment on using a Jensen/Lundahl/Whirlwind transformer splitter (about mic splitting, but still interesting):
"REMOTELESS: Fross, we do this every day with no problems. Using a patchbay with half normalize jacks is how we do it. You will not lose any signal unless there's an impedence mismatch with the gear you are bridging.
Remember, there will be signal loss on the secondary side when using transformers. Not sure why you want to spend the bread for that when you don't really need it. You may need it if the power source is different for the two units you're attaching together, but in most cases (when proper wiring is in place) you're looking good without them.
If you want really hot signals, have you considered line drivers?
In this situation, I believe transformers is not the way to go for this. Whirlwind has a "Jensen" spec transformer. Not too expensive, but a good old "Y" cord (or half normalled jack field) is the better way to go. It's cheaper too."
Any thoughts? I am about to buy a Behringer and get it over with...
What about building one more B1 buffer preamp for the 2A3 amplifier to make the impedances more equal for all the amps and just use a y-cable? The preamp was designed to solve impedance issues.
Again, Nelson Pass saves the day?
Hi,
I am building these nice stereo hornspeakers. I have been using a minidsp 4x10HD digital crossover device with good results. It has been helpful to find the right crossover points. The Minidsp device is digital and degrades the signal and with horns you can really hear it. It also adds hum to my tube amps, forcing me to use an anti-hum isolation transformer that also degrades the signal. I would like to avoid it all together, but the JBL 2225H 15" midbass and the Eminence LAB12 subwoofer works best with an active crossover, so why not use it for them. I doubt I can hear much difference on bass anyway.
I have borrowed a crossover design from Klipsch for the horns that I am pleased with so far.
Situation:
LP-player(unbalanced)/Computer with LYNX L22 sound card (balanced or unbalanced) -> splitter of unknown kind->
-> Analog 2nd XO for mid horns and horn tweeter -> 2A3 tube amplifier
-> Minidsp+DIRAC device subwoofer and midbass-> B1 Buffer preamp+DIY F5 amplifier for midbass, and 800W PA amplifier for subwoofer.
Question:
What kind of splitter should I use??
I want to use is a passive splitter, but I read a Y-cable would lead to impedance mismatch and ground issues. I could use an active splitter, but I would like to avoid it. A good active splitter without added noise is expensive. The Behringer ULTRALINK PRO
MX882 is in my price range but probably noisy. I have not had any luck finding a schematic for an unbalanced active splitter yet. I was hoping I could build a passive splitter with Lundahl transformer, but some of the comments (read below) suggests I should not.
I have done (part) of my homework and found these comments:
On line splitters:
"RONALD DUMSFIELD: Provided that both input impedances are sufficiently high and more or less equal if you split a signal into two there will be no loss of signal quality but the strength will be halved. Resulting in a 3dB loss. So if you keep on doing it eventually it's going to effect your S/N ratio. The convention is you can safely split up to 3 times provided you have sufficient gain available. Which you probably have. Extra cable length may also lead to noise if you have a ground issue.
Unbalanced line level splitters (and combiners) are rare. You can see the problem. Connecting together the grounds on several consumer grade appliances spread over a wide area is almost certain to lead to ground loop issues. That is why professionals use something called a distribution amplifier for this task. It not only splits (or combines) a signal it also converts unbalanced to balanced and provide a small amp per channel to adjust the gain. You can get cheap ones from the likes of Berhinger and ART or top of the range from Drawmer and Radial.
MUSIC Group
Drawmer Electronics - DA6
I still think that if the OP has the cash he would do best with a basic audio interface which is designed for the task in hand. And many other useful functions. You can get a 2 in 2 out unit with headphone from around $150. better would be 2 in and 4 out which starts at ~$200. If that's too steep then stick with a simple Y lead for now and hope you don't get a ground loop."
A comment on using a Jensen/Lundahl/Whirlwind transformer splitter (about mic splitting, but still interesting):
"REMOTELESS: Fross, we do this every day with no problems. Using a patchbay with half normalize jacks is how we do it. You will not lose any signal unless there's an impedence mismatch with the gear you are bridging.
Remember, there will be signal loss on the secondary side when using transformers. Not sure why you want to spend the bread for that when you don't really need it. You may need it if the power source is different for the two units you're attaching together, but in most cases (when proper wiring is in place) you're looking good without them.
If you want really hot signals, have you considered line drivers?
In this situation, I believe transformers is not the way to go for this. Whirlwind has a "Jensen" spec transformer. Not too expensive, but a good old "Y" cord (or half normalled jack field) is the better way to go. It's cheaper too."
Any thoughts? I am about to buy a Behringer and get it over with...
What about building one more B1 buffer preamp for the 2A3 amplifier to make the impedances more equal for all the amps and just use a y-cable? The preamp was designed to solve impedance issues.
Again, Nelson Pass saves the day?
Last edited:
I wouldn't worry about a spliter. You can use an active crossover in software on you computer and configure your soundcard to output hf and lf out of seperate channels. If your soundcard is only 2 channel you can add a usb dac, or use the headphone out for bass to just try. Both Pure Music or JRiver have crossover options, worth checking out. With my setup, Pure Musics active crossover has no decernable loss in quality, while my experience with minidsp mirrors yours, hums, flat sounding, etc.
Still trying to flesh out all the details on my horn setup. Finally bought a minidsp umic to see whats going on.
Sent from my iPhone using Tapatalk
Still trying to flesh out all the details on my horn setup. Finally bought a minidsp umic to see whats going on.
Sent from my iPhone using Tapatalk
My Lynx L22 sound interface ($640) has only 2 channels. I am currently using digital crossovers and I want to get away from digital. I need an pure analog solution, at least for the mids and highs. Problem is I don't know which splitter to use. A Y-kabel would half my output, and I like my output from the source to be as strong as possible. It also presents other issues. So passive splitting is problematic.
Anyone with a good buffered active splitter for unbalanced signals, like those from a tape player?
I think the source of your signal degradation is more likely from ground loops than the "digital" degradation from your miniDSP. I also have 108dB sensitive horns and don't have a problem with signal degradation. Try to use power supplies that are non grounded 2-prong and ground signal shields on one end only. Most grounded RCA cables don't do this and can be source of ground loops.
I think staying all DSP has huge advantages in flexibility and minimal signal degradation of done right. Adding passive (and non adjustable) passives may or may not improve things.
If you really want good ground loop isolation. Try isolated DC to DC converters with kV isolation. Murata makes these and you can use them to power a preamp and your miniDSP to remove ground loops.
Look for pro audio headphone distribution amps - they use a basic op amp and serve well as buffers or pre amp without adding noise. They are also not expensive to try.
I think staying all DSP has huge advantages in flexibility and minimal signal degradation of done right. Adding passive (and non adjustable) passives may or may not improve things.
If you really want good ground loop isolation. Try isolated DC to DC converters with kV isolation. Murata makes these and you can use them to power a preamp and your miniDSP to remove ground loops.
Look for pro audio headphone distribution amps - they use a basic op amp and serve well as buffers or pre amp without adding noise. They are also not expensive to try.
No, I am giving up mixing tube amps with Minidsp - too much noise. Already tried an isolation transformer and it worked to some degree, but I am not spending more on Murata isolation transformers, trying to fix something Minidsp already should have fixed.
I guess an op amp splitter will do fine, but I was hoping for something more extravagent using passive components and a well planned PSU.
I guess an op amp splitter will do fine, but I was hoping for something more extravagent using passive components and a well planned PSU.
Last edited:
I was starting to think about this as well. I am glad someone has the same idea. How would we split the signal then?
Er... two wires from B-1 output.
The HP function for the midrange horn might be done with C-R or C-R-C-R the last R being amplifier's input resistance. I guess a value between 22-82 nF for C.
The other wire goes to the miniDSP input ( if you use it ).
Ohh I see, the mini DSP performs the splitting between Wf and mid-Wf , so a R-C net before the mini DSP is required to limit HF signal.
The HP function for the midrange horn might be done with C-R or C-R-C-R the last R being amplifier's input resistance. I guess a value between 22-82 nF for C.
The other wire goes to the miniDSP input ( if you use it ).
Ohh I see, the mini DSP performs the splitting between Wf and mid-Wf , so a R-C net before the mini DSP is required to limit HF signal.
By "wire" do you mean "RCA Y-cable", likes this one? https://files.cablewholesale.com/hires/30r4-03200.jpg
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