Isn’t that a preamp?
Somebody Please Make This Already...
Imagine an interesting new product: Two sets of analog inputs (when I say sets, I mean each set has single-ended and also balanced), one volume attenuator that controls output synchronously BY WAY OF TWO SETS OF SYNCHRONIZED RESISTOR LADDERS (analog-domain attenuation, not digital) between the two sets of inputs, and then matched sets of outputs (again, both, single-ended and balanced). The entire device should be active, so that if you use single-ended input, it can still output a balanced, differential signal after the volume control, and on the output end there should be an option to combine L/R signals into a single signal (like an LFE output).
Even better yet, we should allow adjustable high-pass filter on the first set of in/outputs and an adjustable low-pass filter on the second set of in/outputs. Slope and frequency should both be adjustable. And of course both filters can be separately bypassed.
The unit should also have a single 12V trigger input and three 12V trigger outputs, and it should have a remote control that can control volume, filter slopes and filter frequencies.
-Ed
22 responses Add your response
I have yet to see any device that synchronously controls the volume level of two entirely separate signals, preamp or otherwise. With this device, for example, you can have full-range or high-pass filtered L/R signals from a DAC go through input 1 and a separate, full-range or low-pass filtered L/R signal go through input 2. The signal going into input 1 would go out to your power amp(s) and can be high-pass filtered by this device if the source signal is full-range. The signal going into input 2 would go out to your subwoofer, where you can apply a separate low-pass filter with this device or your subwoofer if it’s a full-range signal. You can then level-match the sub to the speakers using the subwoofer’s volume control, and then from there adjust the entire system’s volume in-sync. You otherwise can’t do this if there’s no bass management upstream. So you could call this more of an independent bass-management system more than you would a preamp, especially if you sell this without a remote control. Some people also don't like the idea of digital volume control, so something like a WiiM Ultra streamer, despite having bass management, controls volume digitally. This device would allow an analog, resistor-ladder volume control to be used even with bass management, while keeping the sub and speakers level-matched. -Ed |
Why do you need two synchronized volume controls? I assume you have 2 amps, one SE and on XLR. you want them to go up and down at the same rate but how are you going to set them at the same level to begin with? so you have to ask for an adjustable offset between the 2 outputs. This is already available for AV--any AV receiver allows you to set the levels of each speaker or even automatically does it for you with a microphone. If you are looking for something for your 2 channel system biamped, I think you’re looking for a custom piece. Jerry |
@carlsbad2 this is really more of a bass management issue than anything else. I suppose an AV receiver would solve this issue as long as it sounds as good as the end listener wants. Some people prefer to use their own DAC (for the speakers), which they would deem better sounding than the DAC in any AV receiver of similar affordability, but don’t want to use digital volume control (upstream of the DAC), so they want the analog output of the DAC (even if high-pass filtered at the digital level before the DAC) and the (analog) signal to the subwoofer to be volume synchronized when raising and lowering volume. The subwoofer itself has its own volume control to ensure they are set appropriately versus the speakers to begin with. I’m sure you and many others would consider this a solved issue by simply, "settling," for either digital volume control upstream or using an AV receiver instead of proper high fidelity separate components (high-end DAC, pure power amplifiers etc.). I never said I expected this product to sell in the hundreds of thousands of units, but there are definitely niche uses for this. I posted this same idea to Reddit and someone else responded with, "Interesting. Like a stereo subwoofer pre-amp with L-R stereo attenuation. Could be very useful for people like me with no attenuation available on my power amplifiers, they are at 0db all the time. I’m currently using my pre-amp for volume / source selection but a little floor noise gets through when nothing is playing / quieter passages. This device could fit between my crossover and power amplifiers to allow attenuation at that point, but i’ve yet to find a device that covers this." And another person also suggested this device can be used in the process of comparing amplifiers. There are numerous potential uses for this device as I’ve outlined it. -Ed |
I didn't suggest using an AV receiver for 2 channel sound. I just was addressing if you want to use it for AV. Now I know you're looking for subwoofer volume control. I don't use subs but I know that many subs have a high level input so the sub and speaker are driven off the same wire. I know a lot of sub users have solved this and now that they know what you're asking, maybe they will have some suggestions. Jerry
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@carlsbad2 while I get what you're going for, unfortunately, high-level input is implies that the loudspeakers are not high-pass filtered, which is part of the main goal here. Thanks anyway, though! -Ed |
@eddnog We looked at something like this but the simple fact is to do bass management properly you start with a distributed bass array; four subs placed asymmetrically so to break up standing waves and thus have flat bass response everywhere in the room. At that point you really don't need much for bass management other than a subwoofer amp which has its crossover, phase and level all in the same box. IOW if you do the bass right, you don't need a product like this. |
@thecarpathian i haven’t seen too many preamps with full bass management including separately adjustable high- and low-pass filter frequencies and slopes. Much more basic sub outputs and non-adjustable crossovers, yes, but even those there aren’t a whole lot of. -Ed |
I use 2 Mcintosh C50 preamps. 1 to control my main speakers and 1 for my 3 subwoofers. Bass output of the extremely diverse music I enjoy varies greatly and this ended up being the best way to remedy the problem. After time I pretty much know where each volume goes in relationship to one another. I looked for a preamp with 2 separate volume control for 2 separate outputs for years and had no luck, so I sympathize with Ed's conundrum. |
The market is crying for a preamp with proper bass management. Straight through, HP out, Variable LP output, variable frequency and at least a couple HP/LP slopes. both balanced and unbalanced. Inputs and outputs. Throw in source switching, stereo/mono/l/r switching and a balance control, use some quality parts, and you're done. It's not that tough. |
Feel like a Parasound Halo 6 comes close. You want closer? Then I’m with BigKidz. Build your own. There are some great tutorials on doing this. I don’t have steady hands and can’t do what a preamp manufacturer can do with those little British fingers. Next question you need to answer before making your dream machine, tube or solid state? Bass management via tube could be so much fun. How’s your trig? I love algebra so much. Any who, Find yourself an old power amplifier and use the chassis. Send pics when done. I’m envious of your upcoming project. |
