Hi atledreier,
I also have 2 PSC2.400D modules which I am now builing into a cabinet. Anyway the pitch is a standard 2.54mm, so any IDE cable should fit, wouldn't want to power these modules true a <1mm wire though...
Can you indicate what kind of hiss level I can expect? The sensitivity of my system is 92dB for the woofers & 95dB for the tweeter. Much lower than yours but your statement got me kind of worried
I also have 2 PSC2.400D modules which I am now builing into a cabinet. Anyway the pitch is a standard 2.54mm, so any IDE cable should fit, wouldn't want to power these modules true a <1mm wire though...
Can you indicate what kind of hiss level I can expect? The sensitivity of my system is 92dB for the woofers & 95dB for the tweeter. Much lower than yours but your statement got me kind of worried
My Klipsch RF-82 speakers are listed as 98dB/m and I have very little audible hiss in those. I think you'll be fine.
Powering is currently done through the DSP board via the same thin connectors, so I guess if it's good enough for Hypex it's good enough for me. I'll only be running the modules at idle anyway, so not alot of power draw.
Edit: looking at the Hypex pinout I see they are using 4 pins each for positive, ground and negative power supply, and five pins for each speaker pole, so I guess they DID think about it...
Powering is currently done through the DSP board via the same thin connectors, so I guess if it's good enough for Hypex it's good enough for me. I'll only be running the modules at idle anyway, so not alot of power draw.
Edit: looking at the Hypex pinout I see they are using 4 pins each for positive, ground and negative power supply, and five pins for each speaker pole, so I guess they DID think about it...
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I have a couple of questions for Atledreier:
1. Why did you choose the PSC2.400 for home use? It is targeted for pro audio where noise figures are less important.
2. You have high effeciency speakers, why take a product with such much power? More power=more gain= more noise.
3. Did you short the input's from the UCD400 modules to check where the noise is coming from: amp or dsp?
With your setup will be better of with a volumecontrol between the dsp and amps!
Regards Gerhard
1. Why did you choose the PSC2.400 for home use? It is targeted for pro audio where noise figures are less important.
2. You have high effeciency speakers, why take a product with such much power? More power=more gain= more noise.
3. Did you short the input's from the UCD400 modules to check where the noise is coming from: amp or dsp?
With your setup will be better of with a volumecontrol between the dsp and amps!
Regards Gerhard
Well, the Hypex amps are noted as very quiet, so I thought I'd get rid of my noise issues once and for all. About the power figure, I'm a firm believer in headroom, so more power is better in my opinion. I already downgraded from 2kW amps to the 2x400W Hypexes, that's about as far down as I'm prepared to go. In my previous setup it was also the DSP that gave me issues, the amps were quiet, as I suspect is the case here too.
I had hopes for the MiniDSP, but Hypex claim it's the same DSP chip and they have taken steps to ensure it's as quiet as possible. The weird part is that I've spoken with alot of people with sensitive horn speakers and none have mentioned any issues with hiss with any combination. But I can't see the hiss coming from anywhere else in my setup.
I had hopes for the MiniDSP, but Hypex claim it's the same DSP chip and they have taken steps to ensure it's as quiet as possible. The weird part is that I've spoken with alot of people with sensitive horn speakers and none have mentioned any issues with hiss with any combination. But I can't see the hiss coming from anywhere else in my setup.
What about the 3308?
Should I build my own DSP from scratch? I have no illusions that I'll get it quieter than MiniDSP or Hypex.
This weekend I'll dissect one of the amps and try it without the DSp board just to make sure that is indeed the problem. If it is, I'll need some options and routes to try.
Should I build my own DSP from scratch? I have no illusions that I'll get it quieter than MiniDSP or Hypex.
This weekend I'll dissect one of the amps and try it without the DSp board just to make sure that is indeed the problem. If it is, I'll need some options and routes to try.
No, in fact there are already build out of the box, just plug them and use them (look for evaluation boards)
I see.
As far as I can tell there is 10 inputs, but you only select one, and can have that spread to the 6 outputs. So I'll need 3 boards for this to work.
Still, from the specs this doesn't seem to be any quieter than the others. it's on par with the Hypex DSP specs, and the MiniDSP have some 7-8dB better S/N ratio in their specs. Now, the MiniDSP specs are likely bloated.
As far as I can tell there is 10 inputs, but you only select one, and can have that spread to the 6 outputs. So I'll need 3 boards for this to work.
Still, from the specs this doesn't seem to be any quieter than the others. it's on par with the Hypex DSP specs, and the MiniDSP have some 7-8dB better S/N ratio in their specs. Now, the MiniDSP specs are likely bloated.
Of course, I was just messing with you!
I used to use the Behringer DCX2496 that has 3 in 6 out. But similar noise issues there. I figured that was because the DCX had insane gain on the outputs, it will easily put out 11V to the analog outputs. back then the amps themselves were quiet, it was DSP that was noisy. I figured a consumer-level DSP would be quieter. My mistake.
I used to use the Behringer DCX2496 that has 3 in 6 out. But similar noise issues there. I figured that was because the DCX had insane gain on the outputs, it will easily put out 11V to the analog outputs. back then the amps themselves were quiet, it was DSP that was noisy. I figured a consumer-level DSP would be quieter. My mistake.
If you search around a little you will see that many use this one with a volume pot after the DCX exactly because of the noise issues !
Keep in mind that if you have an amp channel capable of feeding 400 Watts into a speaker with a sensitivity of 100 dB you will have a system that can supply an insanely loud 126 dB (the inevitable power compression not taken into account). Now you take a DSP system with an SNR of 100 dB approx (which is quite high compared to what is stored on most program material, and definitely slightly higher than CD standard) you can easily figure out how much noise you will have ! Now take into account that you have multiple speakers each with more than one amp channel ........
Sometimes people forget that dynamics is not only about how LOUD one can go but how quiet as well.
You definitely have a system that can't walk normally because it has too many muscels.
There would of course be a remedy by inserting some voltage divider between DSP and amps (maybe you can make it remote controllable).
Regards
Charles
Well, the problem isn't my speakers or the amps, it's noisy DSPs. If the system is dead quiet without the DSP and noisy with DSP, I blame the DSP. I'm not about to cripple my speakers' dynamic abilities (which is why I built them in the first place) because you think headroom doesn't matter.
So my search for a quiet DSP continue.
So my search for a quiet DSP continue.
Again...the easiest solution is to reduce the gain in the HF channel. The so-called-noise-problem is due to the used DSP nothing else. Probably we can help by modding the HF channel.
Jan-Peter, I realize I may come across as overly negative to your product. i'm really not at all. I love how the amps sound, and on my Klipsch speakers where the noise is less of an issue they are top notch. And these are really the lower end of your range, I'd love to hear the high-end stuff!
The DSP2W board has a maximum output of 9 (or 13) Vrms (i.e. same ballpark as the DCX2496), while for 400 watts into 4 ohms you need 40 Vrms. Required gain thus would be about 13 dB - the amp provides 13 dB more (26 dB total), hence DSP noise will be correspondingly higher.
That's why reducing DSP output level is the way to go. Nothing wrong with a bit of headroom, but 10 dB less should be easily doable.
It's quite amazing how a seemingly large dynamic range on paper (you'd think a little over 100 dB would be nothing to sneeze at, right?) can turn out to be insufficient in practice just because it gets shifted by transducer sensitivity. This kind of thing actually is very common in the headphone world, as sensitivities there may vary by up to ~40 dB.
If you've got very sensitive speakers, the best idea probably is aiming for around 110 dB SPL at the listening position for maximum DSP output, regardless of amplifier capabilities. With 103 dB / 2.83 V speakers at typical "hi-fi" listening distances that'll probably mean the amp will never have to output more than 5 to 10 watts. Which is why people were able to rock the house with that kind of power in the olden days. Amps with more power gave speaker designers the option of reducing sensitivity in order to improve other parameters.
That's why reducing DSP output level is the way to go. Nothing wrong with a bit of headroom, but 10 dB less should be easily doable.
It's quite amazing how a seemingly large dynamic range on paper (you'd think a little over 100 dB would be nothing to sneeze at, right?) can turn out to be insufficient in practice just because it gets shifted by transducer sensitivity. This kind of thing actually is very common in the headphone world, as sensitivities there may vary by up to ~40 dB.
If you've got very sensitive speakers, the best idea probably is aiming for around 110 dB SPL at the listening position for maximum DSP output, regardless of amplifier capabilities. With 103 dB / 2.83 V speakers at typical "hi-fi" listening distances that'll probably mean the amp will never have to output more than 5 to 10 watts. Which is why people were able to rock the house with that kind of power in the olden days. Amps with more power gave speaker designers the option of reducing sensitivity in order to improve other parameters.
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