I have a few old 15" woofers and a lot of odds and ends of compression tweeters in the junk pile. Combined with a few Hafler Transnova amps I have refurbished I thought I might make a few biamped speakers for general yard/pool party use.
If I understand the typical modern speaker that is designed to be biamped (not biwired) when you remove the bars that connect the woofer to the tweeter you are left with a low pass to the woofer and a high pass to the tweeter. I would probably just do an active cross over before the amps and do away with any circuits post amp.
But it occurred to me that lots of modern AV receivers can reassign the back surrounds to be used for biamping the fronts. And they have that automation where you plug in a microphone and they do room optimization. Would they be smart enough to approximate some sort of cross over function in the biamping? Do these tuning systems do any equalization? Or do they just control the relative volumes in expectation that the right cross over is already there?
Best,
John
If I understand the typical modern speaker that is designed to be biamped (not biwired) when you remove the bars that connect the woofer to the tweeter you are left with a low pass to the woofer and a high pass to the tweeter. I would probably just do an active cross over before the amps and do away with any circuits post amp.
But it occurred to me that lots of modern AV receivers can reassign the back surrounds to be used for biamping the fronts. And they have that automation where you plug in a microphone and they do room optimization. Would they be smart enough to approximate some sort of cross over function in the biamping? Do these tuning systems do any equalization? Or do they just control the relative volumes in expectation that the right cross over is already there?
Best,
John
If you have to ask the question, then yes it is going to be a challenge to improve on your current situation that way.
I have another suggestion, why not leave the passive crossover and perform global EQ. This will ensure you can make an improvement.
I have another suggestion, why not leave the passive crossover and perform global EQ. This will ensure you can make an improvement.
The speakers are not yet built. So there is currently no cross over to leave in place. The idea is to skip that entirely.
No receiver's auto-eq system is going to decide it should put a crossover between discrete speaker channels. Some may set a crossover between any channels set as 'small' and the LFE channel, but that is usually a manual setting and quite limited, not really suitable for crossover duty.
You can do what you want by feeding the multi-channel analog inputs on the receiver from the outputs of an active XO. This will give you synchronized volume control for all channels. The easiest way would be with an XO with analog outputs, like a minidsp 2x4hd or the dayton dsp unit. A better but more expensive way is to keep the signal digital, using a minidsp Nanoavr-dl to pass 7.1 channels of lossless PCM over HDMI to the receiver. That gives you enough channels to do a stereo 3 way + .1 channel for sub(s).
In any of these cases, you MUST use a receiver with a proper 'pure direct' mode, that does not apply it's own filtering or delays to any channels.
You can do what you want by feeding the multi-channel analog inputs on the receiver from the outputs of an active XO. This will give you synchronized volume control for all channels. The easiest way would be with an XO with analog outputs, like a minidsp 2x4hd or the dayton dsp unit. A better but more expensive way is to keep the signal digital, using a minidsp Nanoavr-dl to pass 7.1 channels of lossless PCM over HDMI to the receiver. That gives you enough channels to do a stereo 3 way + .1 channel for sub(s).
In any of these cases, you MUST use a receiver with a proper 'pure direct' mode, that does not apply it's own filtering or delays to any channels.
Thank you Morbo I think I understand. For my current application I think I will retreat to simplicity. I think I have some old M&K line level crossovers around here somewhere. If not I will go with something active with rca in/out.
But I am fascinated by the minidsp Nanoavr-dl you have put me onto. I scanned the manual. Do I understand correctly that I could program the crossover across 2 of the outgoing HDMI sound channels for each speaker? I couldn't tell if I could also program some delay to time align. And then I just get a used but high end HDMI AV receiver that is obsolete because it doesn't have ARC return or other modern features to run it all into? If so, that is fantastic. I will definitely cook up a project based on that idea.
But I am fascinated by the minidsp Nanoavr-dl you have put me onto. I scanned the manual. Do I understand correctly that I could program the crossover across 2 of the outgoing HDMI sound channels for each speaker? I couldn't tell if I could also program some delay to time align. And then I just get a used but high end HDMI AV receiver that is obsolete because it doesn't have ARC return or other modern features to run it all into? If so, that is fantastic. I will definitely cook up a project based on that idea.
The Nanoavr is an 8-in 8-out device so you have a lot of flexibility in using it. I have one of these in my computer nearfield system right now. I believe my use case is the same as yours - take a 2 channel stereo signal, up to 24/96 (the native sampling rate of the nanoavr) and split it into different passbands for different drivers. The way it works in my case is - my pc is set to output audio over HDMI (as LPCM), 2.0 channel stereo. The hdmi out goes to the hdmi in on the nanoavr. The nanoavr takes the 2.0 channel and routs a copy of it to tweeters, woofers, and sub. Then each of those channels has appropriate PEQ, delays, and crossover applied to it. The hdmi out is then routed to a ~10 year old Pioneer Elite receiver with a proper 'pcm stream direct' mode that disengages all delays, dsp, and bass management in the receiver.
As an aside - when looking for a suitable receiver, aside from the usual power/distortion/snr measures, I believe the relevant spec to look for on the receiver is HDMI 1.3b or 1.4 support. Before that HDMI revision, LPCM over HDMI was only supported up to 2 channels, and you will need to send full 7.1 channel LPCM over HDMI to the receiver for this to work. My receiver is the VSX-72TXV and I paid maybe $250 CDN for it. It is a MOSFET model, stable into 4 ohm loads and has plenty of power for all but the sub, but nearfield it's fine even for that. I believe an even better candidate would Elite models from the 1-2 years where Pioneer had just started going Class-D for amplification, and was using proper ICEpower modules for amplification. Later they designed their own cheaper d3 amps, which would still serve but not quite as well.
The interface on the NanoAVR assumes you are using it to to process a 7.1 channel surround signal, usually in between a source and a receiver lacking room eq or good bass management. Because of this, it's not quite as intuitive as it could be, but it's really not bad at all. I'll post a few screenshots so you can see how it looks on my system.
The routing screen - in my setup, FL/FR are L/R woofers, SL/SR are L/R tweeters, and C is a subwoofer. But you can see that I could have all sorts of routing arrangements..
The main interface - levels, delays , polarity inversion etc are set here. For each channel there is also an Xover and PEQ screen:
In both cases, you can enter basic settings via the gui, or paste in biquads calculated in REW or your XO sim tool of choice to the advanced section.
There are also per-channel compressors, but I haven't touched those at all so can't speak to them.
It's quite powerful and simple to use really. I also have Hypex Fa123 plate amps, and I prefer the minidsp interface over hypex filter designer by a fair margin; it supports direct biquad input, is more responsive, stable, and less glitchy than HFD.
Absolutely fascinating. My audio hobby has always been old school analogue. I like to tinker with old tube stuff and horn drivers. But I am good at computer stuff and I did do physics and EE degrees back when there was a lot less physics and EE to learn. Looks like it is time for the two halves of my brain to arrange a meeting. I even have a couple of old Pioneer Elites around. I always buy them if I see them at thrift stores or garage sales. I guess it is those rosewood side panels.
Thanks again for taking the time to explain it all.
John
Thanks again for taking the time to explain it all.
John
If you use a PC with HDMI as music source, you can install Equalizer APO and run the crossovers in the PC and feed it to the AVR (direct mode or similar) via HDMI . No hardware needed, and SW is free. Use one driver per channel and filter them as you please, delays, FIR, IIR- A lot more processing power in the PC than a miniDSP.
Beware of the time delays from the AVR for speaker distance, that can give you trouble if you don't have a mic & SW to verify your system.
Beware of the time delays from the AVR for speaker distance, that can give you trouble if you don't have a mic & SW to verify your system.
Also interesting. I presume someone makes a HDMI to rca or XLR outputs with decent DACs? Then I could use my Hafler amps rather than an AV receiver.