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Forums     Discussions     Announces, Releases and Discussions Voxengo 5.1 Bass Management System (alpha)

Alpha version of a new BMS-51 plug-in has been released.

It works pretty much like other bass management systems in existence (hardware ones included), but it also allows you to select LFE channel index.  You can adjust the gain of original LFE channel signal and also change

the gain of the sum signal which is being mixed in to this LFE channel.

The function of this system is basically simple: it extracts the low-frequency signal from broadband channels (L, R, C and others), sums extracted signals and adds this sum to the LFE channel in the specified proportion.

Low-pass filter's rolloff is controllable in 0.1 dB/oct steps.  But please note that rolloff near the Cutoff frequency is around -12dB/oct and is not considerably affected by the Rolloff setting.

Please note that this is a 6in/6out effect, supports all sample rates.


Does the system actually subtract from the main channels, or simply add the content to the LFE?

What I mean is, if for example a figure of 80Hz is selected, does this mean that there will be nothing below that figure in the main channels themselves, or does it simply add to the LFE in addition to the mains?

If so, then it would be a good idea to have an option for switching behaviour from HPF mode to an additive mode instead.


Because you should not use the LFE as a replacement for the bass, but as an extension.

LFE is not the same as subwoofer - and the main channels really should all be full range, and treated as such - especially for DVD-Audio material.

DVD-Video material too should have full range in at least the front Left/Right pair, and ideally across the rest of the system too if Music mixes are being prepared.

The only time the centre channel and surround pair should be bandwidth limited is for Movie soundtracks, and even then at the discretion of the producer.

The way that a consumer grade system with Sub/Satellite setups works is via it's own internal crossovers - which vary wildly from system to system.  We have no way at all of knowing what these crossover points might be, and to use a BM tool as a way of extracting bass frequencies from the main channels is inevitably going to lead to a great big hole in the audio spectrum at one point.

Unless the tool is used properly, and only as a way of checking how the mix will sound across a Bass managed system.

Which brings us right back to the problem of not knowing what the consumers crossover point actually is.

If such a tool is used to produce the mmix in the first place, again there are going to be serious problems when it comes to the mix translating top other systems.

Can I give you an example?

The Pioneer 563/565 range of DVD players, when playing back from it's analogue outputs for DVD-Audio, has an internal crossover point to the LFE of everything below 200Hz.

This has led to an awful lot of posts on firums from angry users wondering where all the bass has gone.

In a similar way, using a Software BM tool will cause much the same problems.

Suppose I try to play back a mix where a BM tool has been used during mixing, with the HPF set to 120Hz.

This means that I will have nothing below 120Hz in any of my 5 main channels, which are all set up with full range operation in mind.

Also, if - as is common - the playback system does not actually have an LFE (You do not need one if you listen to music only, and your 5 main channels are full range) then you will simply hear no bass below that figure of 120Hz at all.  It will be missing.

Multichannel Audio Specialists

DVD-A, DVD-V Authoring

Mixing & Mastering to most formats

Yes, it substracts the low-pass'ed signal from the broadband channels.

OK, your post does make sense.  I will add the option of leaving broadband channels intact.

Do you have any other thoughts of what you want to see implemented in such bass management system?

I will sit down and have a long, hard think about this.

One thing does occur to me off the top of my head though.

Would it be possible to implement alternative configurations?

What II mean is, say, 2.1 or 4.1?

There are a lot of systems these days, BlueSky is one that instantly comes to mind, that use a 2.1 monitoring system.

This way, it will be possible to emulate those kind of systems as well.

This type of flexibility seems to be virtually absent in software.

Multichannel Audio Specialists

DVD-A, DVD-V Authoring

Mixing & Mastering to most formats

I will try to implement variable channel count (I'm actually very interested in this, but to date I was not able to figure out how to do this in VST realm).  Will post more details later.  Thanks for your request!

Do you have any other ideas for this plug-in?


I tried your Bass Management System on the latest Version of Cubase SX 3.

Not sure if I use it correctly (I put the Plugin as an insert on a 5.1 master bus) but it seems as if it would mix tracks together and make some kind of mono tracks. from FL and FR

I am unable to get bass on the 4.  Channel (which is in Cubase per default the Channel for LFE)

And finally it seems as if the tracks are out of sync when the plugin is active, I mean it sounds as if there is some delays between the tracks or as if the tracks are not really synced together.

BTW I use the "Bass Manager" Plug in from Kelly Industries and it works smoothly on my system.

(For the umprobable case you would not know this plugin, here is a link:

I sadly have no further idea for this plug but I do second all suggestions of neilwilkes

(though I cant really believe that someone using a bass management system plugin would have the idea to downmix with the plug active ;-)




I finaly did get the chance to try it out.  Like teacue I had the same problems with the pluging (Nuendo 3.0.1 so basically the same setup).

I found this way of thinking a while ago.

Myself I prefere to avoid using the LFE channel for surround music and considering all the 5 channels to actually be fullrange or let the end user system deal with that (like I do with the Genelec seup, 85Hz crossover and everything below routed to the subbase).

You mention variable channel count... would that be able to solve the fact that if you set the PrestineSpace to 6ch in/out it works in Nuendo on 5.1 OR stereo channels but will not even load in Wavelab?  A separate "always stereo" version would of course also solve that.

Thanks for your feedback.  I'm working on the updated version and fixing issues.  If I succeed with 'auto channel switching' in bass management plug-in, it will be possible to implement this into Pristine Space as well.
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