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Multiband compressor 6 years 1 week ago #26847

  • bcodemz
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We currently have a compressor on the miniDSP, but it is only a single band compressor, making the application extremely limited. Could you add a functionality for a multi band compressor? This would be extremely useful for sealed subwoofers or 2 way speakers to set limits for different compressor settings for different frequency bands without the volume dropping for the entire band when a strong bass signal happens. A 3 bands or higher compressor would be very useful.

This should be trivial to do if a single band compressor code is done. All is needed is to separate one band into 3 bands like a crossover, apply the compressor, and then sum the signal together. The computational horsepower is there for a 4 band compressor, since we can use 4 compressors for each of the 4 crossover bands. Since the compressor is usually only used for the bass channel, it could be done for only one crossover band if computational power is limited.

I hope miniDSP can add this extremely useful functionality. It also helps that it is simple to implement.
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Multiband compressor 6 years 4 days ago #27000

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@ bcodemz

Thanks for the feedback... miniDSP is the company name, more than 30 DSP platforms.. Can u pls clarify which one we're talking about here? :-)
It all depends on the software/environment/resource still available in the dSP. in 90% of cases, all plugins run at 95% of processing power, so sometimes adding DSP isn't easy.. :-(

Once we know more, we can add to whish list. Sounds good?
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Multiband compressor 6 years 4 days ago #27007

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@ bcodemz

Thanks for the feedback... miniDSP is the company name, more than 30 DSP platforms.. Can u pls clarify which one we're talking about here? :-)
It all depends on the software/environment/resource still available in the dSP. in 90% of cases, all plugins run at 95% of processing power, so sometimes adding DSP isn't easy.. :-(

Once we know more, we can add to whish list. Sounds good?


I was specifying the miniDSP 2x4 and the miniDSP 2x4 HD, but I think all of the miniDSP products would benefit.

We know that running 4 compressors is definitely within even the miniDSP 2x4's capabilities, so theoretically a 4 band compressor can be made for one crossover band if we're willing to disable the compressor functionality for the other 3.

Right now, I am making a 2 band compressor by splitting the <300Hz range into 2 bands, one for 65-300Hz, and the other one is <65Hz, and I apply different compressor settings for each band, and then I use an analog stereo to mono adapter to sum the 2 outputs into one. Ideally I would like to be able to just sum output 3 and output 4 together, and output that summed signal into output 3. Summing 2 signals should be trivial in processing power.

I say these are easy to implement because the most engineering heavy part of the feature is all complete, which is the single band compressor. To implement a multiband compressor is simply using an additional crossover on the crossover band, and applying the limiter, and sum the signal back into one. All the code is already written, it just needs to be pieced together.

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Multiband compressor 6 years 18 hours ago #27086

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This is important to me as well. Rather than multiband I suggest parametric compression. I think that it could be cleanly implemented by selecting a PEQ tap and switching it from eq to compression so that each comp tap replaces an eq one.

This is an example of parametric compression


Notice how it compresses only the frequencies that cross the line and not a whole range of frequencies like a multiband or the current compressor does.
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Multiband compressor 5 years 11 months ago #27511

Hi,

I'd also be very interested to see this.

As a feature it would enable us to maximise a drivers capability.

Ideal:
A dynamic eq (or parametric compressor as described) would be the nicest way to implement it. But I assume it would involve significant development.

Practical first step:
Perhaps the easiest improvement is to add a simple 'matrix style summing bus' after the DSP output channels and before the physical outputs. This way the existing crossovers could be utilised. I.e. basically recreating the analogue summing system described in the previous post with software prior to the output.

I'd like to see it on the mini shark platform. The 8dsp channels could be put to great effect in a 2or 3way stereo system.

Thank you

Phil

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Multiband compressor 2 years 11 months ago #43792

I would also like to see a multiband compressor feature. This is a feature of oem subwoofers but does not seem to be available for DIY or non-powered subwoofers. Without it you have to throw away amplifier power by compressing the whole range or use an underpowered amplifier. I'm looking at the SHD to integrate a pair of DIY subs which is a primary use of this processor but even at this price point I can't equal what OEM's do. Seems like it would be a great differentiator from other sub integration options out there if the SHD has the power to do it.

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Multiband compressor 2 years 10 months ago #44155

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If you have an SHD, you'd have sub on a specific channel. Correct? If so, you wouldn't need a multiband. You just put the comp/lim on that specific SUB channel. That's the properway to tune a 2.1/2.2. we'd think.. at least that's how we have it here in our listening room.. :-)
www.minidsp.com/applications/audio-strea...integration-with-shd

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Multiband compressor 2 years 10 months ago #44156

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@[email protected]

If you have an SHD, you'd have sub on a specific channel. Correct? If so, you wouldn't need a multiband. You just put the comp/lim on that specific SUB channel. That's the properway to tune a 2.1/2.2. we'd think.. at least that's how we have it here in our listening room.. :-)
www.minidsp.com/applications/audio-strea...integration-with-shd

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Multiband compressor 2 years 10 months ago #44157

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@[email protected]

If you have an SHD, you'd have sub on a specific channel. Correct? If so, you wouldn't need a multiband. You just put the comp/lim on that specific SUB channel. That's the properway to tune a 2.1/2.2. we'd think.. at least that's how we have it here in our listening room.. :-)
www.minidsp.com/applications/audio-strea...integration-with-shd

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Multiband compressor 2 years 10 months ago #44206

Hi, thanks for getting back! But it seems you may have missed the point of this topic. It applies more to DIY where the properties of the woofer and amplifier are known. Woofers are either excursion limited or power limited depending on the signal frequency and level that is applied. For example, a particular woofer in a sealed cabinet might be able to handle it's full power without damage down to say 50hz, below that it is excursion limited so power needs to be reduced to protect the woofer. This is either done by applying a filter for that lower range or a limiter. But a filter will reduce the level even when playing at low levels, which you don't want. A compressor could be used to limit the power to that channel as you suggest, but that means the power level you can play at 50 and above is limited to what the woofer can handle at 20, which you also don't want. The solution is a limiter that can be applied where needed, a multiband limiter. In my case the subwoofers I've nearly completed could gain headroom with this feature, it's not a showstopper, but very nice to have and used by some manufacturers.

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Multiband compressor 2 years 10 months ago #44207

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I can confirm this is exactly the situation I would use this for.

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Multiband compressor 2 years 8 months ago #45309

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I need this!!! This would make subwoofer integration perfect. Frequency dependent compression. That’s all I need

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Multiband compressor 2 years 5 months ago #47093

  • Andre0815
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In my bass-shaker system having a multiband compressor would be great for bringing quieter bass to 0db ! Each band must have a high and low cut value for specifying the band borders.
Please implement it with minAttackTime shortest as possible. 1 or 0.5 ms is the standard.

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Multiband compressor 3 months 5 days ago #60660

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Following.

I also need this for my MiniDSP 2x4HD, to limit excursion at a driver's Fs without applying global equalization. 

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