Official Velodyne Digital Drive thread

[Hotblack Desiato]

Originally Posted by Uncle Eric

I've been taking a leaf out of Spences book tonight and put down Mecha Godzillas remote for a few hours.

I wish i could practice what i preach...Godzuki is gonna need new batteries in his remote soon.



Had my bass playing [IMG]images/smiley_icons/guitar.gif[/IMG] mate round last night...who then proceeded to spend an hour or so tweaking the Eq settings until everything sounded as good as it could to him. To be honest the trace looks about the same but the filters have all moved a few hertz this way or that and the levels up or down a few dB. I'll try and get hold of some before/afterEQ screen shots.



I go along with what's been said by others it's just amazing how much subtle texture this sub reveals in bass, that once sounded just low and loud.



I've disabled the sub's auto power on-off, and plan to leave it permanently powered, does this seem ok? Just wondering as it's relatively easy to turn on/off via the remote if this would be the better option.

[Uncle Eric]

Originally Posted by tyefi

I've disabled the sub's auto power on-off, and plan to leave it permanently powered, does this seem ok? Just wondering as it's relatively easy to turn on/off via the remote if this would be the better option.

Mine is permanently on and I just turn on/off with the remote. Best option IMO

[CarlB]

Any word from Bruce or Curt on whether lowering the subsonic filter slope unduly stresses the sub, giving more depth but taking away something from higher in the frequency range?



Just wondered why the 24db rolloff was chosen as default when it certainly seems these subs are capable of going lower. I tried the 6db rolloff setting but haven't really found any material which illustrates a significant difference yet, so I'm interested in what trade-off may be required for the extra depth on offer.

[Slartibartfast]

Originally Posted by CarlB

Any word from Bruce or Curt on whether lowering the subsonic filter slope unduly stresses the sub, giving more depth but taking away something from higher in the frequency range?



Just wondered why the 24db rolloff was chosen as default when it certainly seems these subs are capable of going lower. I tried the 6db rolloff setting but haven't really found any material which illustrates a significant difference yet, so I'm interested in what trade-off may be required for the extra depth on offer.

That was certainly one of my worries, but there again you could use EQ settings to boost the bass response to bring it flat again anyway. My thoughts on it were that it would only stress the sub if there were actually significant signals present at those frequencies AND you were expecting high spl's. I like organ music which can generate stuff genuinely in the 16Hz region, so I would prefer not to have the bass response rolled off until below that frequency.



With the subsonic filter set to 24dB and frequency 15Hz there is a discernible rolloff from between 20Hz and 25Hz downwards. Setting the subsonic filter slope shallower to 6dB simply allows the sub to play flat lower - nearly to 15Hz.



With the presets you could set it to only do this on say the Jazz/Classical preset for music use where the need to deliver ultimate spl is not an issue, and leave the Movie mode set to the default rolloff to provide headroom for a more explosive presentation. Lots of scope for tinkering here still.

[BruceHall]

Originally Posted by CarlB

Any word from Bruce or Curt on whether lowering the subsonic filter slope unduly stresses the sub, giving more depth but taking away something from higher in the frequency range?



Just wondered why the 24db rolloff was chosen as default when it certainly seems these subs are capable of going lower. I tried the 6db rolloff setting but haven't really found any material which illustrates a significant difference yet, so I'm interested in what trade-off may be required for the extra depth on offer.

First of all, I can't get the stupid grin off my face reading this thread. We put a lot of time and effort into the DD and this thread shows that it is appreciated. Thank you so much.



We chose 24, ironically, because it gives better low bass performance out of the box. The way this works is that a crossover frequency is typically the -3dB point. So, of you imagine a curve that passes up through 15 Hz at -3dB, and flattens at, say, 18 Hz, it will have a steeper up slope and get flat more quickly and thus play louder at frequencies just above 15 Hz, such as 20 Hz. A more gradual slope won't get flat until somewhere in the 20 Hz + range. While there is infrasonic information below 15, it is not, as they say, mainstream - most real room shaking bass is in the 20 - 40 range, so we want the sub playing at full power there. A lower slope would actually ramp up more slowly and not play as loud in the low 20 Hz range. Most of these settings will not much affect the amp headroom - there is quite a bit of that to spare for transients. We pretty much put in as much power as we could get off the power line.



But, as they say, the proof is in the listening! Please experiment and report your results! As they say, it's only software - we can change the default settings in a matter of minutes.



Thanks Again,

Bruce

[cajunlab]

This thread is THE definitive DD thread.

The UK definitely has a greater appreciation for the finer things in life

Thanks, Bruce!......and Eric!

(from the US)

[CarlB]

Bruce,



Thanks very much for a clear explanation. I've really been testing the sub with some music today and have found an album which is pure demo material - 'Do you like my tight sweater' by Moloko. The amount of seriously deep bass, which never even came close to sounding overblown or distorted (preset 4 - jazz/classical) was phenomenal.



It was like listening to the album for the first time. Quite shocking really, as I have hundreds of CDs now demanding 're-evaluation', never mind the 550 DVDs in my collection!



It's gonna be a great weekend...

[Slartibartfast]

I don't wish to contradict Bruce, but I thought it worthwhile showing a couple of pictures of my EQ'd room response to illustrate what happens with the subsonic filter slope.



The only difference between the setup for these two pictures is that in the first, the subsonic slope is 6dB and in the second it is 24dB. The subsonic frequency is 15Hz in both cases. As you will see the response is substantially flatter with the 6dB slope which is mode in which I set up the EQ. But if Bruce is right, I would expect the boosts given at 15Hz, 20Hz etc., would result in a peak in the response there when the subsonic filter slope is switched to 24dB, but the response goes the other way. Strange?



The first picture with slope 6dB...

[Slartibartfast]

And here's the second with the 24dB slope...





Oh, and don't worry about the stuff above 50Hz because that is what I have my crossover set to with my full-range speakers so the DD18 is unable to compensate for any peaks/troughs much above the 50Hz boundary. I need to do some stuff with bass traps to help with the rest of the response.

[Madge]

Surely it's worth taming those two peaks, or at least the lower one? Unless you're running a brick wall crossover (which the Theta might allow you to do )