Recently, a thread about "what do you prefer about passive crossovers" got me thinking about active crossovers and active (powered) multi-way loudspeakers, and how this has to be more of less "cobbled together" using external parts. For example, if I want to make a 3- or 4-way active loudspeaker (and yes, I typically do that) I need two 4-way or a single 8-way active crossover, and that many amplifications channels as well. My wife is very opposed to a cable morass that tends to occur when all these components are external and not in a dedicated cabinet of some kind, so I have always wanted to build everything into the loudspeaker. This would leave a power cable, and line in or (even better) wireless audio bringing the audio signal to the speaker(s). Unfortunately I have just not found good, compact, multiway amplification and DSP or other active crossover units that can be built into the loudspeaker simply and easily. So this thread is my daydream about what these components would look like. I invite you to put down your thoughts about the form/format that these physical components might use.
As an example, let's say I want to build a 3-way loudspeaker in an box. If electronics were available in a half-rack 1U size format they could be very easily built into a recess of this size in the rear of the loudspeaker. Amplifiers would be 1 or 2 channels, and a 4-channel DSP unit would provide enough analog I/O to run everything. I can sort of put this together now, from some components that I own, but not without some issues. Half-rack amplifiers are available, for example the small class-D amps like the TPA325x series, or even class AB amps, for example the Parasound Zamp v3. The problem is that these will generate heat and that would have to be removed, probably using a fan to pull air in/through. It's not exactly ideal to have a fan in your loudspeaker!
Most components generate heat, of course amplifiers but even line-level ones. Why not place 25-40mm deep heat sinking on the front panel, taking up the entire panel itself? If the components are assembled in a stack similar to a PA rack, the heat sinks would line up to form a taller one. I/O lines that lead external to the loudspeaker could come out of a separate panel, or from the crossover unit. Internal connections for AC mains power and speaker wires would be made via terminals on the side opposite the heatsink, the "inside", where they can be out of sight.
I think that this kind of market is probably quite small, since it would be specific to DIYers only. It would make things relatively simple, however, and I think it would be much more versatile than plate amps. Who knows, maybe it would become popular. You know: "build it and they will come". The user could add as many channels as he/she wishes using additional amplifier or crossover modules. The small "stack at the back" would keep things tidy and would simplify construction.
So, what do you (dear reader) think about this idea? Are there any other concepts/ideas for built-in active loudspeaker components? If you are a manufacturer out there and listening, this is a thread you might want to follow. We could use your input as well.
As an example, let's say I want to build a 3-way loudspeaker in an box. If electronics were available in a half-rack 1U size format they could be very easily built into a recess of this size in the rear of the loudspeaker. Amplifiers would be 1 or 2 channels, and a 4-channel DSP unit would provide enough analog I/O to run everything. I can sort of put this together now, from some components that I own, but not without some issues. Half-rack amplifiers are available, for example the small class-D amps like the TPA325x series, or even class AB amps, for example the Parasound Zamp v3. The problem is that these will generate heat and that would have to be removed, probably using a fan to pull air in/through. It's not exactly ideal to have a fan in your loudspeaker!
Most components generate heat, of course amplifiers but even line-level ones. Why not place 25-40mm deep heat sinking on the front panel, taking up the entire panel itself? If the components are assembled in a stack similar to a PA rack, the heat sinks would line up to form a taller one. I/O lines that lead external to the loudspeaker could come out of a separate panel, or from the crossover unit. Internal connections for AC mains power and speaker wires would be made via terminals on the side opposite the heatsink, the "inside", where they can be out of sight.
I think that this kind of market is probably quite small, since it would be specific to DIYers only. It would make things relatively simple, however, and I think it would be much more versatile than plate amps. Who knows, maybe it would become popular. You know: "build it and they will come". The user could add as many channels as he/she wishes using additional amplifier or crossover modules. The small "stack at the back" would keep things tidy and would simplify construction.
So, what do you (dear reader) think about this idea? Are there any other concepts/ideas for built-in active loudspeaker components? If you are a manufacturer out there and listening, this is a thread you might want to follow. We could use your input as well.
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Well, there are processors and then there are amplifiers, and you may mount all those on the same old 19" rack system. Multi-way processors do exist and some popular ones are Datasat (DTS) AP20, Dolby CP850, DBX Driverack 260, Behringer DCX2496 etc.
I think the in-built crossover and amplifier method you mention is called "powered speaker" or something along those lines. There are a few like that, with everything including the power supply fitted into a recessed portion of the back panel. However, these are not DIY, they're commerical products that I'm sure someone here owns.
I was planning on some "DIY" thing like that (without the built-in part) for 16 channels, with legacy decoding, bass management, crossover, equalisation, limiting and time alignment, all in a single box like a cinema processor. As extra features, I had thought of amplifier control (using external pulse), remote control and a digital recording output.
I think the in-built crossover and amplifier method you mention is called "powered speaker" or something along those lines. There are a few like that, with everything including the power supply fitted into a recessed portion of the back panel. However, these are not DIY, they're commerical products that I'm sure someone here owns.
I was planning on some "DIY" thing like that (without the built-in part) for 16 channels, with legacy decoding, bass management, crossover, equalisation, limiting and time alignment, all in a single box like a cinema processor. As extra features, I had thought of amplifier control (using external pulse), remote control and a digital recording output.
There are 2 and 3-way plate amplifiers with built-in DSP available, most are Expen$ive but I have seen some from far east distributors that don't cost much.
So, you want to build your speaker wide enough so that a 19" rack fits INSIDE it??? Be my guest. That's not what I want to do.
I am talking about narrow form factor electronics, 9" wide or less, that can be built INTO the rear of the loudspeaker to make an "active loudspeaker".
I haven't seen too many 3-way DSP plate amps...
The plate amps by Hypex are indeed expensive. Also, I think that 500W per channel, or even 250W/ch, is overkill. I would take a 100W@8R, 150W@4R per channel, or even half of that, when combined with something small and passively cooled.
Dear Charlie,
I got your point. However, I suggest that you read the whole passage. Multi-way boxes with only a power cord already exist, there's nothing novel about it. Besides, there are modules that allow DIY implementations, as already mentioned by conanski.
EDIT: Also, my processor idea was not for a 19" rack (that's an industrial size). I only intend to adopt the features of commercial processors not their sizes. Besides, since amplifiers and power supplies could be sources of electromagnetic interference, I prefer them in a separate enclosure.
Cheers.
I got your point. However, I suggest that you read the whole passage. Multi-way boxes with only a power cord already exist, there's nothing novel about it. Besides, there are modules that allow DIY implementations, as already mentioned by conanski.
EDIT: Also, my processor idea was not for a 19" rack (that's an industrial size). I only intend to adopt the features of commercial processors not their sizes. Besides, since amplifiers and power supplies could be sources of electromagnetic interference, I prefer them in a separate enclosure.
Cheers.
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I like the offering from Zoudio but the amps (50W/4Ohm) won´t be sufficient for many.
Especially when I think of heavily EQed woofers for an open-baffle speaker.
It´s only a question of time until somebody realizes something similar with a TPA325x or so.
Class-D-amps are small enough though that you could take your DSP-board of choice plus your favourite 4-channel-amp plus SMPS and put it in the speaker enclosure.
Another forum member has done many designs of amplifier-"HATs" for the Raspberry Pi:
Class-D – #360customs
Especially when I think of heavily EQed woofers for an open-baffle speaker.
It´s only a question of time until somebody realizes something similar with a TPA325x or so.
Class-D-amps are small enough though that you could take your DSP-board of choice plus your favourite 4-channel-amp plus SMPS and put it in the speaker enclosure.
Another forum member has done many designs of amplifier-"HATs" for the Raspberry Pi:
Class-D – #360customs
I have used Hypex FA123 in two projects of 3-way speakers. It shoud be quite easy to set 3rd amp to feed mid and tweeter with passive xo in a 4-way. It's power is adequate for normal domestic hifi listening. More powerful modules are much bigger. Some have reported of quality issues, but I've been lucky.
The board is perforated, so the amp must have an airtight compartment inside the speaker, but this is ok for typical 3-way floorstanders.
Using encasement as heatsink would be a good idea, but I guess even Genelec doesn't do that with their Al-boxes. I don't know why, it should be easy.
Putting only amps modules inside the cabinet is another option, classD don't make much heat. One challenge might be how to avoid wall fuse from blowing when all amps get power on simultaneously... soft start or stand-by state that keeps capacitors loaded?
The board is perforated, so the amp must have an airtight compartment inside the speaker, but this is ok for typical 3-way floorstanders.
Using encasement as heatsink would be a good idea, but I guess even Genelec doesn't do that with their Al-boxes. I don't know why, it should be easy.
Putting only amps modules inside the cabinet is another option, classD don't make much heat. One challenge might be how to avoid wall fuse from blowing when all amps get power on simultaneously... soft start or stand-by state that keeps capacitors loaded?
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I got a couple of miniDSP's ICE-PWR plate amps. Very nice 2-ch units. Ethernet setup, control, and monitoring. Capable dsp, including FIR. Analog balanced & unbalanced, and AES3 inputs. Decent small form factor.
Only complaint, it was a little more trouble to fit them into a speaker, where they both ventilated well, and kept the rest of the speaker sealed up.
But despite a good experience using them to power a coaxial project, no more plate amps for me.
I said to myself, well i need two wires to a speaker now....AC and signal. Before, I needed one.
(I use multi-strand speaker cable and speakon connectors, good for one wire to a 4-way.)
I still need a processer/interface of some sort, between my multiple sources and the plate amps. Especially if the plate amp has dsp, and I want to send digital to it to eliminate the additional AD conversion at the plate amp, and the DA at the source/interface.
So i kinda came to what am i really saving or cleaning up.
Now I keep a processor that can accept all my sources, digital or analog, next to the sources.
It sends however many processed channels digitally via a single ethernet cable to multi-channel network amplifiers, near the speakers.
It's used pro gear and for less than i see folks routinely spending on better DIY active setups.
Only real caveat to me is the pro amps fans are too damn noisy. I know i can modify their fans to be quieter as I seldom run them where they need the constant cooling, but i've been too lazy.
I would love to see quality home audio multi-channel amps with DACS that accept input via Ethernet (Dante for example). Gain, sensitivity, polarity, and limiting would be all I'd ask of the amps' dsp.
Keeping filters in the processor makes more sense to me, as processor filter capability is increasing rapidly i think. Would hate to have a locked in investment there.
Software monitoring of each channels' output is pretty cool too ...voltage RMS and Peak, wattage, load impedance, etc. All over the same ethernet cable. I'd want that as part of the amp/DAC package.
Anyway, my 2c thoughts 🙂
Only complaint, it was a little more trouble to fit them into a speaker, where they both ventilated well, and kept the rest of the speaker sealed up.
But despite a good experience using them to power a coaxial project, no more plate amps for me.
I said to myself, well i need two wires to a speaker now....AC and signal. Before, I needed one.
(I use multi-strand speaker cable and speakon connectors, good for one wire to a 4-way.)
I still need a processer/interface of some sort, between my multiple sources and the plate amps. Especially if the plate amp has dsp, and I want to send digital to it to eliminate the additional AD conversion at the plate amp, and the DA at the source/interface.
So i kinda came to what am i really saving or cleaning up.
Now I keep a processor that can accept all my sources, digital or analog, next to the sources.
It sends however many processed channels digitally via a single ethernet cable to multi-channel network amplifiers, near the speakers.
It's used pro gear and for less than i see folks routinely spending on better DIY active setups.
Only real caveat to me is the pro amps fans are too damn noisy. I know i can modify their fans to be quieter as I seldom run them where they need the constant cooling, but i've been too lazy.
I would love to see quality home audio multi-channel amps with DACS that accept input via Ethernet (Dante for example). Gain, sensitivity, polarity, and limiting would be all I'd ask of the amps' dsp.
Keeping filters in the processor makes more sense to me, as processor filter capability is increasing rapidly i think. Would hate to have a locked in investment there.
Software monitoring of each channels' output is pretty cool too ...voltage RMS and Peak, wattage, load impedance, etc. All over the same ethernet cable. I'd want that as part of the amp/DAC package.
Anyway, my 2c thoughts 🙂
Hi Charlie,
I agree shame there’s no readily available solution.
Here’s my engineer’s spec:
4 channels per plate
200+ 200+ 100+ 50W into 4 ohms (enough for virtually all domestic speakers 4 or 3 way- S/W/M/T)
flashable DSP (biquads) with 3 presets, programmable DSP. FIR optional
Self enclosed box with heat sinking and/or temp whisper quiet fans (no louder than typical laptop PC noise) that screws on existing speaker.
Analog in/Digital in.
Forget about Bluetooth and HDMI and other bells and whistles
I’m surprised miniDSP hasn’t created a product for this?
miniDSP?
Okto Research?
Maybe ask Hypex for a 3/4 way 150W/4ohm 3-4 channel product ?
I agree shame there’s no readily available solution.
Here’s my engineer’s spec:
4 channels per plate
200+ 200+ 100+ 50W into 4 ohms (enough for virtually all domestic speakers 4 or 3 way- S/W/M/T)
flashable DSP (biquads) with 3 presets, programmable DSP. FIR optional
Self enclosed box with heat sinking and/or temp whisper quiet fans (no louder than typical laptop PC noise) that screws on existing speaker.
Analog in/Digital in.
Forget about Bluetooth and HDMI and other bells and whistles
I’m surprised miniDSP hasn’t created a product for this?
miniDSP?
Okto Research?
Maybe ask Hypex for a 3/4 way 150W/4ohm 3-4 channel product ?
Feel free to build an amp into a speaker box.
I see no sonic benefits to such ideas.
I much prefer to stay "old school" and have the amp traditionally displayed as a seperate component.
Much easier to service if needed, much nicer to have some knobs easily accessable for adjustments if desired.
I see no sonic benefits to such ideas.
I much prefer to stay "old school" and have the amp traditionally displayed as a seperate component.
Much easier to service if needed, much nicer to have some knobs easily accessable for adjustments if desired.
^^^^^^
This is the problem the market is too small.
The world has moved on from home hi-fi, and the existing enthusiasts are getting grey.
Virtually all portable/battery powered/wireless speaker under 1 litre has DSP and built in multi-way amplifiers and sound incredible compared to what was available in that form factor a decade ago.
Automotive audio sounds amazing- even stock systems in new cars have built in DSP and multi way amplifiers, some with active noise cancellation.
My Yamaha digital piano from 2015 has built in DSP, with FIR and multi-way amplifiers (US$1500, not $15K)
All under the hood, not advertised.
I want my 50L 3-ways to sound like a 200 litre passively crossovered/unequalised 4-ways
Settings for far/near wall placement, bass/treble lift/tilt, excursion limiters etc in case I move the speakers to a different room/house.
But most of the 2 channel crowd wants to keep it old school, so there's NO market to sell these nice plate amplifiers that Charlie et. al dream of.
This is the problem the market is too small.
The world has moved on from home hi-fi, and the existing enthusiasts are getting grey.
Virtually all portable/battery powered/wireless speaker under 1 litre has DSP and built in multi-way amplifiers and sound incredible compared to what was available in that form factor a decade ago.
Automotive audio sounds amazing- even stock systems in new cars have built in DSP and multi way amplifiers, some with active noise cancellation.
My Yamaha digital piano from 2015 has built in DSP, with FIR and multi-way amplifiers (US$1500, not $15K)
All under the hood, not advertised.
I want my 50L 3-ways to sound like a 200 litre passively crossovered/unequalised 4-ways
Settings for far/near wall placement, bass/treble lift/tilt, excursion limiters etc in case I move the speakers to a different room/house.
But most of the 2 channel crowd wants to keep it old school, so there's NO market to sell these nice plate amplifiers that Charlie et. al dream of.
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Long established practices of old school design are not going away, regardless of trendy new devices being pushed on consumers.
True story:
My neighbor and I enjoy sitting on the patio and sharing a couple of beers and conversation on nice evenings.
He's got one of those Bose bluetooth little speakers and listens to Pandora streaming stuff.
Yes, it sounds nice, as you would expect.
Recently, I brought over one of my "old school" portable AM/FM radios, a Panasonic, made in 1969.
I have an FM transmitter in my house linked to my basement shop PC, with Winamp programmed with various genre's of music that we both like.
After a few evening sessions with MY tunebox, his response was "man, that sounds SO nice! - "I'd forgotten how decent the vintage stuff sounded"
So you see, people are now so wrapped up in their digitally manipulated worlds, and when they hear straight analog again without all the digitally modified crap, they wonder what happened.
Indeed, and it is also not very clear as to how the multichannel DSP+amp+speaker would allow simple things like volume, source selection (tape/CD/FM) without a central unit. Maybe remote control can help. I believe that this type of all-in-one solution is more suited to portable PA applications like guitar/instrument cabs and stage monitors. The SRX835P (released years ago) has been a popular model.
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I use AVRs or Yamaha WXC-50 as source. Mid-price AVRs have at least L/R line outs, that follow main volume. WXC is nice but I miss a FM tuner...
There are so many options how to send source signal to dsp and to amps, RCA line level is practical and widely availabe in consumer mid-price products. I don't miss balanced which woud give theoretically better S/N ratio and enable longer runs. Optical or other digital out have typically only one plur on the receiver/source, which means that signal has to be spit and jumped to the other speaker.
Wireless has delay and L/R matching problem - but it's OK for low-fi mono sound boxes on the patio...
Basically I guess we are now discussing diy projects, not serial production or kits? We have so varied personal preferences and different installations, that I can't see a single "best" choice existing...
There are so many options how to send source signal to dsp and to amps, RCA line level is practical and widely availabe in consumer mid-price products. I don't miss balanced which woud give theoretically better S/N ratio and enable longer runs. Optical or other digital out have typically only one plur on the receiver/source, which means that signal has to be spit and jumped to the other speaker.
Wireless has delay and L/R matching problem - but it's OK for low-fi mono sound boxes on the patio...
Basically I guess we are now discussing diy projects, not serial production or kits? We have so varied personal preferences and different installations, that I can't see a single "best" choice existing...
No-one is disputing that vintage stuff doesn’t sounds good.
What I’m are disputing is that, in the same form factor of the AM/FM tunebox (4-5L?) a better speaker can be made today in 4-5L than in 1969, thanks to better amplifiers, better drivers and better crossovers.
What I’m are disputing is that, in the same form factor of the AM/FM tunebox (4-5L?) a better speaker can be made today in 4-5L than in 1969, thanks to better amplifiers, better drivers and better crossovers.
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I would think so too.
People nowadays are moving more and more towards other, more compact solutions like soundbars or tiny bluetooth-speakers.
The DIY-market sure is negligible.
I understand that not all DIY-people like to work on electronics and do metal work but for the price of a Hypex FA123 (which is pretty reasonable) you can easily build something yourself that is cheaper (that is if you consider your own time&effort as "free"), smaller and pretty comparable.
Take a nice slab of aluminium, mount your favourite DSP-board (substitute an analogue XO if you like), amps (like two TPA3220-EVM micro) and a Meanwell SMPS. All in all probably 250€.
Your AVR/Yamaha then is a central unit that commands all the speakers, i.e. it selects the source, receives and decodes data, controls volume and sends it to the "autonomous" speakers.
Each speaker has, on its own, many similar (redundant) modules like power supply and processing. Power supply modules mostly tend to be more compact, EMI-friendly and cost-effective when implemented centrally. Also, the central unit (AVR etc.) often has enough processing capability to carry out the crossover/EQ for all channels. Doesn't such a method increase the costs to non-DIY-friendly levels?
Yes I can easily agree. I am looking at 16 channels with legacy decoding (AC3/DTS/PCM), which makes it very clear that I can't have 16 decoders, 16 processors (DSPs), 16 power supplies etc. However, with a central unit, I can manage with one decoder, two processors and so on.
However, for 3-way/4-way stereo, the processing would be only for 8 channels or less, but the issue relating to power supply redundancy still persists.
Regards.
Well, I didn't start from zero... I had the Yamaha RX-V, turntable, TV, CD and DVD and 5 passive speakers already. I just wanted to make the stereo pair active and 4-way. I use Minidsp 4x10HD for dsp (single external power supply) and a pair of B&O ICEpower stereo modules as amps (each module has it's own transformer) For movies I have a 5.0 system available with just click or two on remote (to select source and set to multichannel)
Other projects utilize Hypex boards, each of which has a single transformer for dsp and amps.
Hum and elevated S/N ratio by picked-up interferences might be a problem with this kind of puzzle systems, but I've been lucky... Shielded RCA cables and a replacing the 4x10HD's broken transformer were the tricks to do!
I am one of those with limited metal and electric working skills, including passive xo design. UMIK and REW plus several iterations of settings was needed to get the best sound out!
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for me, the basiscs would be to make it appealing for me and i guess also the majority of the people
Full containing unit with high quality components. It does not have to be esotheric expensive stuff, but high quality on audio. Especially AD/DA must be adressed (as that is the weak point of many dsp's).
100w/4R per channel would be good enough for me. I prefer discrete AB amps (no typical cheap opamps), altough i can live with class D of the quality of NCore. PSU may be good shielded SMPS, but mainly more than powerfull enough and well shielded (no switching noise).
Simple to calibrate 3way stereo (or dual mono) DSP, dummy proof with mic to measure that is already calibrated to the system. FIR and so are optional but would be nice. An automatic system that works would be a big deal.
Inputs in digital (USB\Coax\Optical) and analog (RCA/XLR), not BT, HDMI or so. Output if it's not a plate amp in speakon or banana plugs.
And this for a reasonable price, not more than an average high quality integrated amplifier (1K) for a whole stereo system all included.
Full containing unit with high quality components. It does not have to be esotheric expensive stuff, but high quality on audio. Especially AD/DA must be adressed (as that is the weak point of many dsp's).
100w/4R per channel would be good enough for me. I prefer discrete AB amps (no typical cheap opamps), altough i can live with class D of the quality of NCore. PSU may be good shielded SMPS, but mainly more than powerfull enough and well shielded (no switching noise).
Simple to calibrate 3way stereo (or dual mono) DSP, dummy proof with mic to measure that is already calibrated to the system. FIR and so are optional but would be nice. An automatic system that works would be a big deal.
Inputs in digital (USB\Coax\Optical) and analog (RCA/XLR), not BT, HDMI or so. Output if it's not a plate amp in speakon or banana plugs.
And this for a reasonable price, not more than an average high quality integrated amplifier (1K) for a whole stereo system all included.