ART Cleanbox frequency response

[blaser]

I'm happy to have dual RL-P18 in 650 L each and a FBQ2496

[Ilkka]

"Let there be bass: and there was bass."

Yes, the mod works. I doubt I have to tell which curve is before and which is after the mod.

I used 1uF 63V polyester capacitors (two red ones in the pic).

[Ilkka]

Chrisbee wrote:

Thankyou for sharing this graph, Ilkka.

How important, in your experience, is the bass roll off of these boxes in the real world?

Do these roll-offs just offer valuable protection to modest subwoofers?

Presumably the effect is very subwoofer dependent?

If a sub can't reach low and loud then it won't notice the high pass effect anyway.

Well naturally one doesn't have to be worried about this all if his sub goes only down to 30 Hz. But if one is after a good output down to 10 - 15 Hz or lower, I would definitely think which EQ to choose. And yes, one easily gains some or actually quite a lot of (excursion) protection with some of these models. But that's actually pretty old news to most of us...

Any kind of filtering (low or high pass) of course always adds group delay, though that's pretty much the least thing one should be worried about at these frequencies.

[Chrisbee]

Thanks, Ilkka.

[pbc]

Ilkka,

Have you tried sending the above shots to Velodyne to get there response? Would this be a software fix or would a resolder/new capacitator fix be needed similar to the ART?

Tx

[JimP]

Over on AVS, Velodyne posted that they were going to update the firmware to allow you to eliminate the subsonic filter which should improve the shape of that curve.

[Ilkka]

pbc wrote:

Ilkka,

Have you tried sending the above shots to Velodyne to get there response? Would this be a software fix or would a resolder/new capacitator fix be needed similar to the ART?

Tx

I haven't sent them, but Velodyne is well aware of the situation. Here's their response (copy/paste from AVS forum):

"The big concern here is some DIYer's want flat response to 5hz or even DC. The current SMS-1 has been designed for the more normal user. There are very few subs that have much energy below 20hz and the SMS is fairly flat to 20hz and not down very much at 15 hz. IMO, it's not wise to eliminate some sort of protection via a subsonic filter or other filtering. However, as I told you we will weigh the pros and cons and demands and address it at a future date. In your case with your bass reflex design subwoofer tuned to 20hz you would not notice any difference at all. Bass reflex designs have an 18db roll-off below tuning frequency and you should not (boost) eq at or below that tuning point. A few DIYer's with several large drivers in a very large enclosure (Infinite Baffle) want to try for flat output down to or below 10 hz. This can certainly lead to problems in the wrong hands. As Art points out humans don't hear much below 25-30hz and even then the signal would have to be at a very high amplitude with very low harmonic distortion to be audible."

But as Jim said, they have promised a firmware update that should completely bypass the subsonic filter. I will measure the frequency response with the newest firmware when it's available.

[brucek]

My goodness..... what a condescending response......

has been designed for the more normal user

DIY'ers aren't normal?

This can certainly lead to problems in the wrong hands.

They're worried the children will hurt themselves. Next they'll be advising not to run with scissors.

As Art points out humans don't hear much below 25-30hz

I would say both Velo and ART are completely missing the point......

brucek

[Ilkka]

brucek wrote:

DIY'ers aren't normal?

You might want to take that back?

I would say both Velo and ART are completely missing the point......

I think he meant some person named Art in the AVS thread where from I copied that reply. But that goes as well with the ART too though...

[pbc]

Thanks Ilkka. Will be interesting to see if they come up with this firmware.

PBC