Call me old fashioned, but I still believe in passively controlling audio level in amplifiers.
Unfortunately the norm has now become receivers, at least if you want to deal with more than two channels.
But my luck with HT receivers has been awful, first a reputable Onkyo one (very heavy) and then a Denon.
Not living in the USA adds up to the problem, because I can't enjoy warranty backup, which on the Onkyo case, having a two-year warranty might have solved my problem.
The Onkyo lasted one year, the Denon two. So I decided never again to get a receiver.
That decision puts you in a difficult position if you still want or use video & audio as your main programming source. Even more if you still want 5.1 or 7.1 audio.
Not willing to extend this introduction much more, let's go to the point. My problem is how to adjust volume levels remotely for 6 channels, that will feed 6 discrete power amps, or whatever amp I use. I do not want to do that setting actively, with a level IC, which is what the majority of receivers use.
That has always seemed to me a low point in receivers design, even if they are extremely sophisticated.
So I decided to try an old-style 6-channel pot, namely a motorized Alps type. Those are still being made and reasonably priced.
What I wonder is if someone has already dealt with such an arrangement, recently if possible. If someone did, please tell me your story and experience. What worked and what didn't.
There are kits available, some of them with input relay-switching controls, with remote and all. Like this one:
MV06 6 Way Input Motorized Remote Volume Control Kit ALPS|alps remote|alps volumealps volume control - AliExpress
Comments, suggestions, input please?
Unfortunately the norm has now become receivers, at least if you want to deal with more than two channels.
But my luck with HT receivers has been awful, first a reputable Onkyo one (very heavy) and then a Denon.
Not living in the USA adds up to the problem, because I can't enjoy warranty backup, which on the Onkyo case, having a two-year warranty might have solved my problem.
The Onkyo lasted one year, the Denon two. So I decided never again to get a receiver.
That decision puts you in a difficult position if you still want or use video & audio as your main programming source. Even more if you still want 5.1 or 7.1 audio.
Not willing to extend this introduction much more, let's go to the point. My problem is how to adjust volume levels remotely for 6 channels, that will feed 6 discrete power amps, or whatever amp I use. I do not want to do that setting actively, with a level IC, which is what the majority of receivers use.
That has always seemed to me a low point in receivers design, even if they are extremely sophisticated.
So I decided to try an old-style 6-channel pot, namely a motorized Alps type. Those are still being made and reasonably priced.
What I wonder is if someone has already dealt with such an arrangement, recently if possible. If someone did, please tell me your story and experience. What worked and what didn't.
There are kits available, some of them with input relay-switching controls, with remote and all. Like this one:
MV06 6 Way Input Motorized Remote Volume Control Kit ALPS|alps remote|alps volumealps volume control - AliExpress
Comments, suggestions, input please?
Another option I considered was coupling 3 x 2-channel remote controlled kits, that might come with legitimate Alps pots, but pot tracking between channels might certainly be a problem
What others existing and more reliable controllers would you suggest? Is there an existing system like that?
There are lots of good ways to control 6 channels and make them track. None are passive. And regardless, a passive volume control needs (or should have) a buffer, since pots make lousy line drivers. And now you're not passive anymore.
Sorry, I don't get it. A 5.1 or 7.1 system, properly set up and calibrated, needs far more than just 6 channels of tracking volume control. Somewhere along the line you'll need to calibrate individual channel levels, crossover frequency, bass management, and oh yeah, decode the source bitstream somehow, and if you want the best possible audio, you'll want the high-end codecs. An AV control system also has to switch digital video sources. Everything I know of that does that already includes a volume control that tracks perfectly.
Receiver reliability can be an issue at certain levels. No idea what you bought, though. I've had two Denons, one is now going on 8 years, no issues, the other when 7 then I upgraded without a failure. These are not flagship units, but near the top of the line.
Onkyo...yeah, many of their units tended to self destruct. Heat was a problem. Low end Denons had issues too, usually with the HDMI board.
But that's no reason to abandon the rather necessary features of a receiver or pre-pro and go back to the stone age, sacrificing all the things that make 5.1/7.1 possible, and done right.
Sorry, I don't get it. A 5.1 or 7.1 system, properly set up and calibrated, needs far more than just 6 channels of tracking volume control. Somewhere along the line you'll need to calibrate individual channel levels, crossover frequency, bass management, and oh yeah, decode the source bitstream somehow, and if you want the best possible audio, you'll want the high-end codecs. An AV control system also has to switch digital video sources. Everything I know of that does that already includes a volume control that tracks perfectly.
Receiver reliability can be an issue at certain levels. No idea what you bought, though. I've had two Denons, one is now going on 8 years, no issues, the other when 7 then I upgraded without a failure. These are not flagship units, but near the top of the line.
Onkyo...yeah, many of their units tended to self destruct. Heat was a problem. Low end Denons had issues too, usually with the HDMI board.
But that's no reason to abandon the rather necessary features of a receiver or pre-pro and go back to the stone age, sacrificing all the things that make 5.1/7.1 possible, and done right.
Hi Jaddie,
First of all thanks for a very detailed analysis, considering most of the factors involved in what I intend to do.
Let's try to explain a bit more on what I think and exercise the imagination on these issues.
There's one that you can't forget considering, which is the reality of someone living in the USA and the reality of someone living in Brazil. You have access to maintenance and particularly prices that I do not have. This makes a HUGE difference when you think about it. I found a similar problem when discussing my HDD array for my video store, everybody suggesting RAID, and doubling the HDDs for protection. Which may mean a reasonable amount of money there, but means a fortune here.
So let's go to analyzing the different stages, and my particular arrangement as I see it.
1) Number of channels. This is probably the most serious matter, as I have my opinions on this that probably differs with most. The question is I really need only FOUR channels: front left-right and side/back left-right. I don't believe in subwoofers, and I find them unnecessary, as long as you have proper woofers or mid woofers, larger than 8", in your L/R front speakers. My room is 40 square meters, so I don't even high power amplifiers, just enough for video programs. My wife will always complain when I try to go higher. My present stereo amp can reach 40 watts @ 8 ohms, and I can only go high when I'm watching just by myself. Center channels are a problem to install on my present setup, and as with subwoofers never felt a need for them. Dialogue plays right in the middle between both speakers. So my real problem is having four channels.
2) Calibration. Being just 4-channels makes setup easy, because I can trim that in the side/back power amps gains or input levels. I'm quite sure I can get a Dolby setting for levels between front and rear channels, which I have the high quality instruments (pro mics and preamps) to fine tune that, at several frequencies if necessary, which I don't is not necessary. The rear speakers I already have, that I used when I had the receivers. Same thing goes for the calibration of the front L/R channels, which a trimpot can spot in, replacing it later with a fixed gain resistor.
3) CODECs. That I solved quite recently, when I found this multi-channel high quality DAC:
Evolve II-4K HDMI v2.0 / Multi-Channel DAC - Essence For High Res Audio
In fact I'm quite sure this DAC is a lot better than those included with any sub $2,000 receiver, don't you think?
4) Source switching. That problem is the first I had to solve, as well as a way to split my HDMI outputs, so I can feed my TV and my projector. That I did. There are many of that around in Amazon, eBay, Aliexpress and many others. With remote and all.
My yet unsolved problem is how to control my audio levels, and adding buffers to them would be a very minor problem. Though I have been using passive pots for many years now, as source levels are quite high now and low impedance, and I'm not quite sure a buffer will improve things up. Though that's very easy to check, even on my present simple 2-channel arrangement.
So I'm not sure I agree with your final comments on going back to the stone age or sacrificing quality. In fact, considering the path the signal goes inside the receivers I would be willing to buy, or bought, I believe shorter paths for signals is a benefit.
My present problem is boxing all the stuff I am using or would use, perhaps putting all the small boxes, at least those for selecting/controlling the sources, on one single box.
Once I thought why nobody made a DAC + preamp combo, charging less than for a receiver. HDMI signals made the world more complicated and more crash prone. As you correctly said, HDMI boards are a very very weak link in receivers, and I'm pretty sure the problem I had on mine were in that area.
The Denon never turned on anymore, but the Onkyo still does. But the HDMIs do not work, so it's useless as a receiver.
Now there's one area I can certainly exceed most sub $3,000 receivers, which is audio power amplifiers. That would be the main reason for assembling a DIY multi-channel system.
Now, if you can think or suggest how to control the multi-channel level control, remotely if possible, perhaps we can start there.
First of all thanks for a very detailed analysis, considering most of the factors involved in what I intend to do.
Let's try to explain a bit more on what I think and exercise the imagination on these issues.
There's one that you can't forget considering, which is the reality of someone living in the USA and the reality of someone living in Brazil. You have access to maintenance and particularly prices that I do not have. This makes a HUGE difference when you think about it. I found a similar problem when discussing my HDD array for my video store, everybody suggesting RAID, and doubling the HDDs for protection. Which may mean a reasonable amount of money there, but means a fortune here.
So let's go to analyzing the different stages, and my particular arrangement as I see it.
1) Number of channels. This is probably the most serious matter, as I have my opinions on this that probably differs with most. The question is I really need only FOUR channels: front left-right and side/back left-right. I don't believe in subwoofers, and I find them unnecessary, as long as you have proper woofers or mid woofers, larger than 8", in your L/R front speakers. My room is 40 square meters, so I don't even high power amplifiers, just enough for video programs. My wife will always complain when I try to go higher. My present stereo amp can reach 40 watts @ 8 ohms, and I can only go high when I'm watching just by myself. Center channels are a problem to install on my present setup, and as with subwoofers never felt a need for them. Dialogue plays right in the middle between both speakers. So my real problem is having four channels.
2) Calibration. Being just 4-channels makes setup easy, because I can trim that in the side/back power amps gains or input levels. I'm quite sure I can get a Dolby setting for levels between front and rear channels, which I have the high quality instruments (pro mics and preamps) to fine tune that, at several frequencies if necessary, which I don't is not necessary. The rear speakers I already have, that I used when I had the receivers. Same thing goes for the calibration of the front L/R channels, which a trimpot can spot in, replacing it later with a fixed gain resistor.
3) CODECs. That I solved quite recently, when I found this multi-channel high quality DAC:
Evolve II-4K HDMI v2.0 / Multi-Channel DAC - Essence For High Res Audio
In fact I'm quite sure this DAC is a lot better than those included with any sub $2,000 receiver, don't you think?
4) Source switching. That problem is the first I had to solve, as well as a way to split my HDMI outputs, so I can feed my TV and my projector. That I did. There are many of that around in Amazon, eBay, Aliexpress and many others. With remote and all.
My yet unsolved problem is how to control my audio levels, and adding buffers to them would be a very minor problem. Though I have been using passive pots for many years now, as source levels are quite high now and low impedance, and I'm not quite sure a buffer will improve things up. Though that's very easy to check, even on my present simple 2-channel arrangement.
So I'm not sure I agree with your final comments on going back to the stone age or sacrificing quality. In fact, considering the path the signal goes inside the receivers I would be willing to buy, or bought, I believe shorter paths for signals is a benefit.
My present problem is boxing all the stuff I am using or would use, perhaps putting all the small boxes, at least those for selecting/controlling the sources, on one single box.
Once I thought why nobody made a DAC + preamp combo, charging less than for a receiver. HDMI signals made the world more complicated and more crash prone. As you correctly said, HDMI boards are a very very weak link in receivers, and I'm pretty sure the problem I had on mine were in that area.
The Denon never turned on anymore, but the Onkyo still does. But the HDMIs do not work, so it's useless as a receiver.
Now there's one area I can certainly exceed most sub $3,000 receivers, which is audio power amplifiers. That would be the main reason for assembling a DIY multi-channel system.
Now, if you can think or suggest how to control the multi-channel level control, remotely if possible, perhaps we can start there.
The above would the the strongest design parameter. Understood.
8" speakers cannot provide the bass extension needed to reach 20Hz at reference SPL. However, that's clearly not your goal. If you want reasonable response in the bottom octave, the 8" speakers will not be able to do it.
Also keep in mind the LFE channel is not just about bass extension. In fact, with your DAC, if it doesn't have bass management, you will end up dropping the primary purpose of the .1 LFE channel: Low Frequency Effects. Bass management has several different modes that can distribute the LFE to other channels...or not, as is the choice and match to the speaker system. I'd check on bass management in your DAC.
SPL and bass extension are two different, but related parameters. You can get bass extension without high SPL, but not with 8" speakers, and not without equalization. Further, low level full spectrum performance mandates an active bass processor of some sort, Audyssey Dynamic EQ is one of them. Again, preference will determine necessity.
But it doesn't unless you sit right between the front speakers. Which you might. Be aware that in any 5.1 mix 70% of the average total energy comes from the center channel. It is therefore the most important. And is always the most difficult to place. You're not alone in ditching the center, but understand that the choice has nothing to do with how important the channel actually is, it's a practical matter, and individuals will often choose to compromise rather than solve the placement issue. Placement is made worse by the fact that to get it right, the center and L/R should all be identical speakers. The specific "center channel speaker" design is another form of compromise that fixes one problem, and creates several others.
Yes, that is a real problem. More on this in 3.
Calibration is not just adjusting levels though. That's the most basic, and necessary, true, but there is much more to do. But what do you do about equalization, "room cal" if you like? Speakers in different positions do not match each other's FR, and that's just the beginning. Pro mics and preamps won't help you here. You specifically need a calibrated measurement mic, which is omnidirectional but calibrated for grazing response or on axis response (you need to know). These are not expensive, but then, you are where you are. Lacking that, a good, true omni mic (not a multi-pattern mic) is a good compromise. Analysis should be done with REW, free and incredibly capable software. You do need a means to get your mic into a computer.
Otherwise, all you're doing is setting channel levels, which is not real calibration. However, if you don't provide any means of calibration, making measurements with a measurement mic doesn't make sense either.
Just note that all of that is built into any mid-price AVR.
One question to answer is the capability of the DAC to provide a valid downmix to 4 channels (no center). I didn't see and documentation on it.
Not at all. Decoding the bitstream, particularly Dolby Digita, TrueHD, and DTS (everything) is a matter of license, and chip sets, DSP software. There are really not that many options. The DAC section uses DAC chips that would be available to any manufacturer. DACs have the least impact on sound quality of any component in the chain. Most of the cost of any audio product is the power supply and packaging. So no, it's not going to be better than an AVR.
Yes, HDMI switching is fairly easy. Be aware there are two manufacturers of HDMI chip sets. Unlikely you're making an improvement here either, though replacement may be less costly.
It looks to me like you're creating a bit of a control nightmare. Having a remote for the HDMI switch, one for the DAC (?), one for the volume control, source device controls, and then...how do you turn the system on and off? Is this something the wife will use, or will you be the Control Tzar? If a system is unusable by a family member, it becomes a questionable investment.
Shorter paths are a benefit, but there's also a practical limit to their benefit. It's not a problem at all to send an analog audio signal over cable quite some distance. But not if it's coming from the wiper of a pot. You'll want a buffer in there. It's possible to have short paths that don't work well and long ones that do. Electronics is involved, it's not a general rule, it's application specific.
The pre-pro market is very tiny, limited to high end. The product does exist up there.
But you said your 40wpc was already too much? Every respectable AVR, event the cheap ones, will do at least twice that. Having equal simultaneous power in all amps is completely unnecessary as simultaneous full power peaks simply do not occur in a 5.1 mix. There is nothing to be gained here except possibly heat management by spreading it out over several devices.
Look at the motor driven multi-section controls (assuming you don't want a DSP or even digitally controlled attenuator in there). There are several VC chips in the world, but again, not sure the cost to your location would be worth it.
Don't under value buffering your passive control. If you had a 10K pot, set mid-resistance, you're driving your load through a rather significant resistor. A buffer drops the source impedance to a couple hundred ohms, and cable drive is no longer a factor. Also, amps may or may not present a strange load. Unless you like the "color" of a high source impedance output, it's just not good practice.
Since this is DIU, make your own. Use 5 (Or 6) Elan VSE-100 transformer volume controls, which can be electrically ganged and operated by a common remote. Transformers will need to be replaced with 600 Ohm TVCs, for example Atlas Sound AT-10 or something fancier. Advantages:
- Remote controlled;
- True free-standing passive pre;
- TVCs are superior to potentiometers;
- Compatible with interconnects;
- Any number of channels.
- Remote controlled;
- True free-standing passive pre;
- TVCs are superior to potentiometers;
- Compatible with interconnects;
- Any number of channels.
My 8" speakers and room allow me to get to 45Hz, flat with the rest. No qualization.
But I will add one NHT 1259 12" driver on each side, independently powered but connected to same L/R output as the mains. That will get me to 28Hz, which should be more than fine. Let's forget about 20Hz.
To start with I do have Dolby and DTS decoding on the media boxes I'm using, so they are doing that decoding. But if I use this external DAC I mentioned, it does decode different Dolbys and DTS too. I'm not so sure I want the eq Audyssey does, which you seem to find mandatory.
Who says I want a downmix to 4? I never noticed any audio or dialogue missing in the 2-channel I have been listening since I lost the receivers, as should be the case. Right now the HDMI audio is decoded to two channels in the converter box I'm using. I would have to find out what the external DAC does. Right now is Kodi that does the CODEC conversion.
No center channel for me. Used many 5.1 setups, with HDMI and without it, and I never lost any center channel specific info. Maybe they do send it if you are using the channel, but I never lost any dialogue or sound because I wasn't using it. That would be obvious if it was missing.
Calibration the why Audyssey, with that mic they use, it can't do much more than adjusting levels. Sorry if I don't really believe there's no speaker or room response being done with it.
Using REW for measurement and setup is something that really does interest me. I have really pro mics with, AKG or Sennheiser condensers, and I can use the Tascam preamps. I have to find out how to connect the Tascam into the computer to use it as preamp, if it's possible.
I'm not aware of any DIY mic preamps to USB that I can assemble. Perhaps the Behringer UCA202 that I have might be my way in, using the Tascam recorder as mic preamp.
Right now the level control is partly on the power amp and partly on the remote of the source device. It would be much better if could use just one volume level: on the power amps.
No problem in trying buffers at the power amps inputs. In fact I can assemble a pair on my prototype boards quite easily, using high quality DIP ICs I have here, and check what happens.
No problem turning things on and off on my present setup. The TV/projector and the signal source: that's all. Nothing more complicated than that. With the receivers it was turning the receiver on/off and turning the TV/Projector on/off. So not that different from what I have now.
Selecting the source is done on a small remote that comes with the HDMI switcher. That I would like to be better.
But one thing I can tell you: many more years have passed by using the HDMI switchers than the ones that passed by using the receivers. Call it bad luck, or whatever you like, but if you can offer me an absolutely reliable option that lasts the 7 or 8 years you mentioned, do you think I wouldn't run and grab it? Do believe I would!!!
It's a pity there are not more affordable multichannel preamp being made, because that is what I would buy. Something costing around $300/500 or so, which is the price those switchers and DACs add up to, more or less. Something reliable and sturdy.
Sounds more like a measurement error. I've measured more rooms than I can count, none were ever flat before cal, even with subs. The room is too small not to have modes everywhere.
Ok. Wrong technique, but whatever. If you want to know how to get the subs to work right, ask. Otherwise I'll assume "mind made up".
Audyssey had several processes, one of which is "Dynamic EQ", which corrects for the spectral offset you get when you play a mix below the reference level it was mixed at. Dynamic EQ "knew" the exact SPL offset, and corrected dynamically. Especially good for low volume listening. But that's just one thing Audyssey can do. It also did room cal. But it's not the only, or even best solution.
I've never found a room, dedicated theater, studio control room, or home, that didn't benefit from equalization. Don't know why people don't seem to even want to try it.
Then obviously, there's a downmix going on somewhere. 5.1 > 2 is common, as is 5.1 > 3, I'm not sure about 5.1 > 4. To get this to work you'll have to "tell" something how many speakers you have, where they are, and what kind. If you didn't do that, you're getting a downmix that may or may not be correct.
And there it is. Downmix of 5.1 > 2. You 're not getting your 4 channels or LFE done right, sorry.
It's not a question of lost dialog, it's a question of localization. You cannot get a stable phantom center image with two speakers, simply not possible in more than one seat. Center speaker completely solves that problem...that is, if you think it is a problem. I happen to think it is.
You have a rather significant misconception. The mic they use is either one of their standardized ones that comes with the AVR, or the calibrated one that comes in the Pro kit. Either way, its response is known. It does MUCH more than just adjust levels. It develops a digital filter that compensates for response in the time domain for each speaker with a measurement procedure called "fuzzy clustering" that improves measurement precision over traditional swept sine chips and spatial averaging, and goes way beyond the RTA from the stone age.
Unless they are at least omni directional, you're not getting good measurements at all. A cardioid condenser will mislead you. Sorry, that's life.
There are several around, I happened to like the UMIK-1 because it's excellent quality, calibrated, easy to use, and works with computers and tablets. There are cheaper ones, none better for the price.
Acoustic Measurement Tools : UMIK-1
I also have an Earthworks M30 with cal curve.
M30 — Earthworks Audio
It's better, but not better enough for the additional cost for most measurement uses. I rarely need that level of precision, but I do use it.
But the mic is the first step, the analysis software is the next, the EQ to respond to your measurements is the final step. Since you're doing all DIY, take a look at the miniDSP products (they do sell just the boards):
miniDSP Webshop | DSP solutions
Sounds difficult to use.
The buffer goes right after the volume control and before the cable that feeds the power amp, not at the power amp input.
Nobody can offer that. Denon used to have a 3 year warranty. HDMI failure was a significant problem about 10 years ago, because of the failure rate I would have to think the problem has been solved. I only had one client with an HDMI board failure in a low-end Denon product, and it was related to a lightning strike.
The problem is, getting it to you in an affordable way, but here:
MC-700 7.1 Channel / 4k HDR / Surround Sound Processor – Emotiva Audio Corporation
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