I have heard that class D amps have decent imaging in general, perhaps not seven in a row in an avr. I could be wrong about it. Maybe a two channel amp would improve the sound stage you're hearing?
You never know until you try, it seems to me.
You never know until you try, it seems to me.
You are implying that all switch-mode power supplies are bad fo audio. That is just not true. The goal of any PSU is to provide one or moe DC voltages with enough current capacity for an amplifier to provide rated power to the speakers. Since a power amp directly modulates voltage from the PSU, havning ANY sort of noise on those DC lines would be very detrimental, regardless of PSU design.
So lets look at two misconceptions:
1. Analog PSUs are always better
2. Switch-mode PSUs are bad for audio
For #1, we need to look at what makes up an analog PSU. Theres a power transformer that takes line voltage down to something appropriate for the amplifier. There's our first glitch. Evern power transformer has series impedance that causes its secondary voltage to change downward with increased current draw. Every single one. The degree is a function of the transformer design, but you never get away from it. Problem 2 is that the line fequency is rectified, so the huge noise that must be filtered off is twice the line frequency, so 120Hz or 100Hz, and that's a pretty big problem. PSUs used for power amps are typically not actively regulated becaue of the high currents involved. So we're left with using a biggie sized capacitor. The problem with those is that the bigger they are the more internal series resistance they have, a parameter called ESR. It's really expensive to get that low and maintain high C. ESR increases charge time and limits discharge curent, tending to mess with our filter. So the short-cut is to use smaller value caps in parallel with the large one for better HF capabilities. But a high current peak will still cause the voltage rails to sag, and recover. And the parts are expensive, inefficient, and the transformer gets hot and has a rather powerful magnetic hum field. Heat is the enemy of all electronics.
Now he have good switch-mode PSUs. The first thing to go away is the huge transformer. Line voltage is rectified, then a chopper regulator reduces its average voltage, followed by a filter. The speed of the chopper (switching) determines the size of the filter network, so higher is better. But we also need to watch for EMI, so shielding is required too. Ultimately, you get DC voltage that is every bit as clean as an analog supply, but without the difficulty of a huge filter cap, AND, with the side benefit of faster recovery from high current draw. The actually can perform better!
There is a bias against switch-mode PSUs because of the switching frequency. 40 years ago that was a real problem. Today, that problem is gone. The cost of good, clean switch-mode PSUs long ago dropped below that of analog PSUs. Throw in the potential for faster high current draw recovery, and you have a win. And ask yourself this: what amplifier, AVR or otherwise, could ever pass a critical review if it had HF junk in its audio output? That would be a big, obvious problem. Intermod products would be all over the audio band, and would pop out of even conventional THD measurements. But we don't see any of that. Precautions have been taken. Heck, even the power supply that drives the DAC and digital circuits is separate from that of the power amp.
The bias for analog supplies is psycological now, but none the less powerful. Plus, if you make a big, heavy amplifier with huge iron in them, then you are justified in charging $60K per channel (yes, that's real), because it takes two people to lift one monoblock. But from an audio standpoint, nothing is really accomplished that a good switch-mode PSU couldn't have done lighter, cheaper and cooler.
I believe we've established that AVRs aren't using Class D. 350kHz is easy to eliminate with a chunk of the right ferrite. Not sure why you'd be seeing it other than incomplete design.
Yep, correct. I don't have one to try on hand. But I also RF proof audio gear all the time because one of my clients has a studio directly under a tower with 7kW of AM radio on it. Slightly higher in frequency, but a ferrite choke does the trick every time, so frankly, I'm surprised its an issue, especially at that level. However, AM radio is modulated, what do you see on that 350kHz? And what problem does it cause?
That RF field the studio is in is high enough that a ferrite choke will get hot to the touch when in use.
Again, we have not confirmed Class D amplifier use in AVRs. The units I've checked use switch-mode PSU and conventional amplifiers.
I've looked at several Class D amplifier application notes and data sheets. Every one of them includes an LC filter. The spectrum shows energy at 350kHz should be down 40dB post filter.
Yep, it's hard to even jam that frequency into a driver because of it's inductance.
If you diy then several excellent quality amps are in your budget. Diy can be challenging but this group is really wonderful at walking you through.
Didn’t read the whole thread
Thanks, but I have no interest in DIY amps. Have done my share of electronics building in the past way back to Heathkits. So, I know how to do it but don't enjoy it all. Rather pay to have someone else do it.
Speaker building is entirely different. I have a very well-equipped woodworking shop, so it fits right in with my other hobby.
I second this.
Look, moving speakers or furniture is essentially free, but absolutely effective.
Changing floor/wall/ceiling materials can be inexpensive and also make a difference.
To simply "answer" your question: conventional knowledge is that speakers make the biggest impact on soundstage, electronics second, EXCEPT for Digital Signal Processing (DSP). "Purists" eschew DSP, but from a purely logical perspective it should work wonders.
I do not own a DSP.
I think of getting one every so often.
Not an issue, HF at audio out is the norm of class-d. I was responding to your previous statement which is not true.
In my experience, soundstage and imaging depend on the following in order of importance:
So for the original post, one can high pass the book shelf speakers and add a bass module and turn them into 3-way speakers would be good. Mr. Bagby wrote about this. For amplification, LSA Warp 1 commercial amp designed by our own here @ diyaudio - XRK audio @ $1200 is a good choice.
Note I haven't addressed other issues such as distortion and tonal balance, etc., just soundstage and imaging.
Enjoy the music!
- Speakers: phase tracking between drivers (closer phase tracking the better), frequency response range (more extension the better) and efficiency (more is better). I think his speakers have good phase tracking but a bit on the low efficiency side (82dB / w?) and little extension (-3dB @ 60 Hz?). Usually smaller, less efficient speakers are more demanding of amplification than larger, more efficient ones.
- Room & speaker positioning: higher and wider room is better, speakers away from room boundary is better, more distance between speakers is better. More diffusion & absorption to an extent is better.
- Amplification - relative to efficiency. Ability to deliver instantaneous current & voltage is better => stiffer power supply is better (eg more capacitance is better). For AVR, the power supply is where many manufacturers skimp so it is usually just good enough but not more.
- Source - less noise, less jitter, lower output impedance is better
So for the original post, one can high pass the book shelf speakers and add a bass module and turn them into 3-way speakers would be good. Mr. Bagby wrote about this. For amplification, LSA Warp 1 commercial amp designed by our own here @ diyaudio - XRK audio @ $1200 is a good choice.
Note I haven't addressed other issues such as distortion and tonal balance, etc., just soundstage and imaging.
Enjoy the music!
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From the data sheets though, it looks like what I said should be true. -40dB at 350Khz, that would be pretty clean.
More and more it seems like the only options insisted on are mid fi, despite how many good suggestions are made.
Lot more fun talking about hi fi. Even something physically larger would be a relief at this point. Interesting colors. A vivid blue maybe. A wi-fi upgrade.
Lot more fun talking about hi fi. Even something physically larger would be a relief at this point. Interesting colors. A vivid blue maybe. A wi-fi upgrade.
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I've come to the realization that in my small room, 10.5' wide by 12' deep, the size of the sound stage I have right now is about as big as it can be with conventional speakers. And it really isn't that bad at all. It's actually pretty good. I started this just to see if there is a reasonable way to expand it even further, but I don't think there is. The room size and shape are limiting what I can do.
I've also changed my goal somewhat. While I would like orchestras to appear larger, I really don't want the same for opera singers. They are just about the right size now. And voices from radio announcers are already on the verge of being too large. If there is a way to change the apparent size for orchestras but then shrink it back down for singers that would be ideal. But I don't think that is possible.
So, for now the goal is to add more bass. And Jeff Bagby's bass module is certainly one of things to consider.