Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Foggyroad]

I had a close call recently when changing a peaking filter in the PEQ. just before turning up the volume I noticed I had typed 100dB instead of 10dB. It could have been a blown driver.  Would it be possible in the PEQ to enable a user setting of an overall limit to any PEQ filter boost eg 10dB or 20dB. If someone wanted to set a larger boost then it could be set to zero. I've often seen people say they won't use software filters just because of this issue. It would offer a bit of protection.

[Matt]

I'd really recommend volume protection.  It will step in front of a huge spike.

If you're not outputting with JRiver volume, the max level probably wouldn't do any damage since a song often has the max level as part of it as well.

[Foggyroad]

Yes, I use volume protection and that works well for protecting the system from a sudden volume change.

However, I don't think it would work to protect drivers if you are doing a PEQ filter change on the fly. For example, if I have the volume set at 85% and I'm playing some pink noise and I wanted to hear how a change in a narrow peaking filter from a 5dB boost to a 10dB boost sounds and I accidentally type 100dB (yes, I know clumsy fingers, but it happens) - that wouldn't be prevented by volume protection would it?

[Matt]

I was trying to add a big volume boost today and volume protection was engaging.

[Foggyroad]

With all due respect Matt, have you tried the scenario I set out in my previous post.

Using a pair of old full range drivers, whilst music was playing I have changed a PEQ filter set at 3kHz (Q2) from 10dB to 100dB and the volume protection does not stop the change. I had the volume set low and there was still a very loud screech from the speakers as the change took effect. Had I been listening at a normal level there is every chance that the drivers would have been damaged.

[Matt]

I just added a "+100.d dB at 3000 Hz (Left, Right)".

The peak level in DSP Studio changes to the words "Protect" which means no audio is coming out.

[Foggyroad]

It seems to depend on what the Peak Level is. If it is above about 10% Protect works, but if it is below that level it doesn't. However, this doesn't solve the problem of potential damage to drivers in my use case - multiway active speakers.

I set up a scenario where Peak Level is at 6% playing JRiver's pink noise (-20dBfs). The volume control is at 80%. The PEQ filter for this driver is bandwidth limited with x-overs at 120Hz and 1kHz and has some other EQ. The filter to change is at 3kHz, Q2 and +10dB, so actually outside the bandwidth, but still having a noticeable effect. I changed that to 100dB and protect does not kick in. Peak level jumps to 100% and in my test my amp shutdown after the test speakers' driver voice coils heated up. In fact they heated up to the point that the speakers no longer work - and they don't smell nice, either. 

I have a video clip of the test, but it appears to be too large to attach here.