KVR Audio

Tagirijus · Post by **Tagirijus** » Tue Sep 18, 2012 8:52 pm

valhallasound wrote: The idea behind the Dark Modes (Dark Room, Dark Chamber, Dark Space, Nostromo, Narcissus, LV-426) is that the reverb is downsampled, so there won't be any signal above 1/4 the sampling rate. The downsampling filter (8th order elliptical, less ripple) used isn't super steep, so the rolloff will probably start happening around 8 kHz for a sampling rate of 48 KHz. Any signal/artifacts above 1/4 the sampling rate should be attenuated by 106 dB, as that is the highest sidelobe for the elliptical downsampling filter.

Hi there,

I also use Valhalla room for my stuff, since I got it. I really love it! Thank you so much for this reverb! Besides I would like to ask a question, which hopefully is tolerated here - even if it's a little bit offtopic:

You already explained the technical idea behind the dark modes. May I ask what the practical idea is? Is it for less CPU usage or something like this in the first place? Or is it only for a different sound? I have to confess that I was sitting many hours switching between the "Large Chamber" and the "Dark Chamber"(filmmusic orchestra context). Somehow I like both, since the Large sounds bit brighter of course, but the Dark sounds a bit more "something is really inside the room". In the end I was wondering, if there is maybe some very basic difference in the usage of these two modes?

Thanks for the reply!

Manu

Edit:
May I add some further question? Your "tutorials" are nice on your site. Nevertheless: you did not mention how to find the right algorithm for the right situation. Of course there are some information about how the algorithms work and so on, but I still do not feel very comfortable with all the algorithm choices. Is there maybe some basic rule or trick how to chose the right one?

Please forgive me for this offtopic. Maybe I should start a new thread in the Valhalla DSP foorum?

valhallasound · Post by **valhallasound** » Wed Sep 19, 2012 12:33 am

Tagirijus wrote: You already explained the technical idea behind the dark modes. May I ask what the practical idea is? Is it for less CPU usage or something like this in the first place? Or is it only for a different sound? I have to confess that I was sitting many hours switching between the "Large Chamber" and the "Dark Chamber"(filmmusic orchestra context). Somehow I like both, since the Large sounds bit brighter of course, but the Dark sounds a bit more "something is really inside the room". In the end I was wondering, if there is maybe some very basic difference in the usage of these two modes?

Thanks for the reply!

The original idea was to reduce the CPU usage, as well as add some interesting coloration to the reverb. Theoretically, a reverb running at 1/2 the sampling rate should use 1/2 the CPU of the full-rate version. In practice (at least with my code) this isn't the case. There is a bit of a CPU reduction, but nowhere near halving the full rate CPU usage.

So the main reason to run an algorithm at a lower sampling rate is for the change in the sound. The steep order filters that I use in ValhallaRoom, when they are *working* (cough), cut out all energy above 1/2 the sample rate. In addition to that, the linear interpolation I use in the Dark modes further reduces the amount of high frequency energy.

I have several half-formed theories about why getting rid of this top octave might be a good idea. However, the original reason was pretty simple: The EMT250, Lexicon 224, and Quantec QRS all have a sampling rate around 20 kHz, and filter out all of the energy above 8 to 10 kHz. People LOVE those reverbs, and I was wondering if part of the reason was due to the lack of high frequency energy. The reactions of people to the Dark modes in VRoom suggests that this might be the case.

In most algorithmic reverbs, the region between 10 kHz and 20 kHz is an area where it is easy to hear any flaws in the algorithm. Get rid of this region, and the reverb sounds better. In addition, many of the producers and engineers that use ValhallaRoom talk about how the Dark modes sit better in the mix than the full bandwidth modes.

May I add some further question? Your "tutorials" are nice on your site. Nevertheless: you did not mention how to find the right algorithm for the right situation. Of course there are some information about how the algorithms work and so on, but I still do not feel very comfortable with all the algorithm choices. Is there maybe some basic rule or trick how to chose the right one?

Please forgive me for this offtopic. Maybe I should start a new thread in the Valhalla DSP foorum?

Feel free to start a separate thread. However, there is no real fixed answer for this. The only strong suggestion I have is to try the Large Room, Large Chamber and Dark Chamber modes for percussion, as these tend to be the densest.

Sean Costello

Tagirijus · Post by **Tagirijus** » Wed Sep 19, 2012 7:33 am

Hi Sean,

Thank you very much for this information. I think I should understand a bit more now. Keep on the good work and have a nice day, by the way!:)

Manu

valhallasound · Post by **valhallasound** » Tue Feb 12, 2013 8:23 am

For anyone who cares about this topic: I am preparing a beta of the ValhallaRoom 1.1.1 update. No new features this time around, just a few bug fixes:

- Aliasing bug is fixed. I'd love to get more people to test this, but a few quick tests show that the brickwall filters are now properly brick walling.

- Dual monitor fix in Pro Tools. I haven't tested this yet, but the new build uses the fixed code from ValhallaVintageVerb, so this should work.

If you are a registered user of ValhallaRoom and you would like to try the beta, send me an email, or PM me with your email address. I should have the beta ready to test sometime tomorrow.

Sean Costello

solidtrax · Post by **solidtrax** » Tue Feb 12, 2013 8:55 am

valhallasound wrote:[..]

- Aliasing bug is fixed. I'd love to get more people to test this, but a few quick tests show that the brickwall filters are now properly brick walling.

I would love to test this for you later today, but can you tell me how to test this? The thing is.. I never noticed it before... (is that a bad thing?)

Normally, I hear aliasing from miles away (in synthesizer plugins) but I never noticed it in your plugins.

valhallasound · Post by **valhallasound** » Tue Feb 12, 2013 5:38 pm

solidtrax wrote:
valhallasound wrote:[..]

- Aliasing bug is fixed. I'd love to get more people to test this, but a few quick tests show that the brickwall filters are now properly brick walling.
I would love to test this for you later today, but can you tell me how to test this? The thing is.. I never noticed it before... (is that a bad thing?)

Well, I didn't notice when I introduced the aliasing bug. It is honestly pretty subtle on most program material. For most music, there aren't a lot of harmonically aligned harmonics above 10 kHz, just noisy transients that don't sound that different when aliased.

To test the aliasing, the best way is to run a sine test tone into the plugin, and set the frequency above 1/4 the sampling rate. If the antialiasing filters work, the output of the reverb should be silent. If they aren't working, the output will be an audible sine wave at some seemingly random frequency.

Normally, I hear aliasing from miles away (in synthesizer plugins) but I never noticed it in your plugins.

Analog synthesizer waveforms have harmonics from DC to daylight. This can result in aliasing when being simulated by a plugin, or can produce audible aliasing in a plugin that has broken antialiasing filters.

Sean Costello

djanthonyw · Post by **djanthonyw** » Thu Feb 28, 2013 3:54 am

Hi Sean, I'm planning on getting VRoom again. Just wondering if the beta that addresses this is ready?

valhallasound · Post by **valhallasound** » Fri Mar 08, 2013 11:14 pm

djanthonyw wrote:Hi Sean, I'm planning on getting VRoom again. Just wondering if the beta that addresses this is ready?

I have a beta out there. Waiting on feedback from users.

Sean Costello

Yorrrrrr · Post by **Yorrrrrr** » Wed Apr 17, 2013 7:51 am

valhallasound wrote:
djanthonyw wrote:Hi Sean, I'm planning on getting VRoom again. Just wondering if the beta that addresses this is ready?
I have a beta out there. Waiting on feedback from users.

Sean Costello

Nice! Could you please add a low cut slider, please?

EDIT: Oh..I just saw in another thread somewhere, that what I'm asking for was planned, but won't be possible in the end (something to do with Reaper VR users)

kimik · Post by **kimik** » Wed Apr 17, 2013 8:40 am

Yorrrrrr wrote:
valhallasound wrote:
djanthonyw wrote:Hi Sean, I'm planning on getting VRoom again. Just wondering if the beta that addresses this is ready?
I have a beta out there. Waiting on feedback from users.

Sean Costello
Nice! Could you please add a low cut slider, please?

yes... +1

Yorrrrrr · Post by **Yorrrrrr** » Thu Apr 18, 2013 9:24 pm

So, how is the beta going? When is it planned for release?

valhallasound · Post by **valhallasound** » Thu Apr 18, 2013 10:06 pm

Yorrrrrr wrote:So, how is the beta going? When is it planned for release?

I'm holding off on the release until I have AAX working.

Sean Costello

Yorrrrrr · Post by **Yorrrrrr** » Sun Mar 30, 2014 6:12 pm

It's really taking long time, nearly a year now

valhallasound · Post by **valhallasound** » Sun Mar 30, 2014 7:05 pm

Yorrrrrr wrote:It's really taking long time, nearly a year now

Please send all complaints to support@avid.com.

The OSX beta, with fixed aliasing artifacts, has been released as a beta for the past few months:

http://www.valhalladsp.com/aax-updates

Sean Costello

Yorrrrrr · Post by **Yorrrrrr** » Sun Mar 30, 2014 8:38 pm

Hehe, effing AAX ports..they're useless to me, as Windows ports are what I'm looking forward to.

Keep up the good work Sean.

Valhalla Room aliasing artifacts