TOPIC:

When using SHD with analogue-in, and analogue-out, what is the maximum gain, or is it just zero? Thanks in advance.
FYI, not a user yet but keen to get one into my system

My understanding is that Dirac attenuates the signal by 10dB to allow it some headroom to boost into.
The SHD then allows gain up to 0dB, ie. unity.
You can then add gain to specific channels in the plugin if required.
So it all rather depends on what room correction Dirac applies but is likely to be close to unity.
In my case there was sufficient gain to replace a preamplifier.

The analogue inputs and outputs have the same maximum levels. If you drive the inputs at full level there can be no more than unity gain.

Thanks for sharing your personal experience. As you've probably guessed, am keen to know if I will need a pre-amp in addition to the SHD; definitely keen to avoid it. Cheers

entripy wrote:

My understanding is that Dirac attenuates the signal by 10dB to allow it some headroom to boost into.
The SHD then allows gain up to 0dB, ie. unity.

From other threads I've seen here it's not clear to me this definitely happens. Version 1 of Dirac appeared to have a control for attenuation to apply but v2 does not. Here's a current thread discussing this but without resolution:

www.minidsp.com/forum/shd-series/16778-s...stortion-2-ch-purity

sweemeng.lim wrote:

Thanks for sharing your personal experience. As you've probably guessed, am keen to know if I will need a pre-amp in addition to the SHD; definitely keen to avoid it. Cheers

What sources do you want to connect? Most won't need any gain. My SHD is actually currently sitting on top of an unused analogue pre-amp.

The answer to your question though is that up to 12 dB gain can be set on each output. I realise that without knowing for certain what Dirac does this isn't entirely useful information though .

Dirac Live 2 is unable to compensate for frequency response dips larger than 10dB for me, which suggests it still has 10dB attenuation like DLCT defaulted to.

entripy wrote:

Dirac Live 2 is unable to compensate for frequency response dips larger than 10dB for me, which suggests it still has 10dB attenuation like DLCT defaulted to.

Have you read the thread I linked to? The OP gets distortion unless he keeps the master volume below -10 dB, which suggests automatic attenuation may not be applied.

Yes I have read that thread. I am only confident in my own experiences though, where Dirac Live 2 operates identically to DLCT defaults in respect of its apparent attenuation. I am, umm, fortunate to have rather large SBIR suckouts which make the behavior obvious without a sub. It is annoying that Dirac Live 2 hides this though.

entripy wrote:

Yes I have read that thread. I am only confident in my own experiences though, where Dirac Live 2 operates identically to DLCT defaults in respect of its apparent attenuation. I am, umm, fortunate to have rather large SBIR suckouts which make the behavior obvious without a sub. It is annoying that Dirac Live 2 hides this though.

Could you maybe reply to the other thread with your experience? I'd like to discuss this more but it would be more appropriate there.

Thanks you both for your input.
To answer a specific question, I'm using a PS Audio DAC which has a relatively lower (in comparison to others) output signal; some find this a problem while others have not - associated problems with this has also been discussed on forums elsewhere. Feeding it directly into a power amp, the max volume through my rather insensitive speakers doesn't quite work for me.

Consequently, am hoping there's enough gain in the SHD to avoid the need to include a pre-amp.

What I can gather from the discussion so far (rightly or wrongly), is that the average SPL gain of 12dB is available, whereas the 10dB limit stated elsewhere really reflects the amount of attenuation (to the various frequencies?) available - is this correct?

BTW, is anyone aware of manufacturer's contract details, so that they might put this to rest? Their online help isn't very useful, or maybe I've just overlooked something obvious.

Thanks again & regards

It's difficult to predict anything. I went from using a preamp to just the SHD and it obviously has less gain than the preamp. But it has enough for me to run the SHD at -20dB normally, -15dB on quieter sources, so there is still apparent gain left unused. It now goes to just louder than I need rather than much louder than I need.

In my case the power amplifier gain and input sensitivity were known, my power amplifier needs less than 1V to be driven to full power and the SHD can output 2V so it likely has enough output voltage to drive most power amplifiers. If you know the output level of your DAC and the input level of your power amplifier you know how much gain you need for nominal full levels. If that is less than12dB the SHD can likely drive the power amplifier adequately.

But there's really only one way to know for sure, Calibrate your room and see if your system goes loud enough. The nominality of most levels means the margin of error on calculations makes a calculated answer approximate at best and uselessly misleading at worst.

sweemeng.lim wrote:

To answer a specific question, I'm using a PS Audio DAC which has a relatively lower (in comparison to others) output signal; some find this a problem while others have not - associated problems with this has also been discussed on forums elsewhere. Feeding it directly into a power amp, the max volume through my rather insensitive speakers doesn't quite work for me.

Are you talking about feeding the analogue output of the PS Audio DAC into an analogue input on an SHD? This would render the PS Audio DAC pretty pointless to be honest and you may as well just use the SHD as a DAC instead. If people want to use a different DAC with an SHD the logical place for this is after the SHD, not before. I appreciate this wouldn't solve your level problem though.

sweemeng.lim wrote:

What I can gather from the discussion so far (rightly or wrongly), is that the average SPL gain of 12dB is available, whereas the 10dB limit stated elsewhere really reflects the amount of attenuation (to the various frequencies?) available - is this correct?

Not quite. Firstly the 12 dB gain is an absolute figure not some sort of average. All signals can be increased in amplitude by up to 12 dB.

Dirac complicates the picture. The issue is that if this applies boosts to try to fill in dips in a frequency response then this itself increases the peak levels. If you have a low amplitude input signal then this is no problem, but if the input includes peak levels close to the allowed maximum then this can result in clipping (a bad form of distortion). This can (and should) be prevented by additional attenuation. If such attenuation is applied automatically then it would essentially cancel out the potential 12 dB gain and so the answer to your original question would be that the SHD can't apply any significant gain for you. If on the other hand such attenuation is not applied automatically then in your situation you could actually have more than 12 dB overall gain. Unfortunately it is currently unclear which of these last two situations applies, as is being discussed in another thread. If you really want to persue this I would suggest contacting miniDSP support but to go back the point I made right at the start of this post, I don't think it is sensible to connect a PS Audio DAC to an SHD input in the first place.

sweemeng.lim wrote:

BTW, is anyone aware of manufacturer's contract details, so that they might put this to rest? Their online help isn't very useful, or maybe I've just overlooked something obvious.

Use the Support link at the top of the page to submit a query. If you do find out anything useful I'd be grateful if you could post back here to share it .