Eighteensound 18NLW4000

vertx wrote: I probably need a better LMS with Dynamic EQ too so the balance is better early on when there's less people on the floor...

toastyghost wrote: Earplug wrote: IIRC, member      RC1 Sound System was developing something. Here:- https://forum.speakerplans.com/dj-sound-system-volume-levellers_topic101739_page1.html That’s the Leveliza already discussed. It’s not a protection device per se. Very useful if there’s no tech on site, or to allow one to have a break, but it won’t save the kit from being melted.

vertx wrote: So I've actually got a Drawmer SP2120 In between the DJ mixer and the DBMark XCA but I prefer it not in the signal chain, I can hear the difference... plus it's another point of possible failure. I though the Drawmer was actually a limiter, rather than a gain reducer/controller? I know the XCA has AGC on the input but I don't think it's good for music... I probably need a better LMS with Dynamic EQ too so the balance is better early on when there's less people on the floor... Something to bring the LMS input gain up slowly throughout the course of the night, automatically, would be good too. Drawmer between LMS and mixer, then automatic slow gain rise based on set times to peak when the headliner comes on....

It’s an install. Does it sound better with the Drawmer in the chain than it does without it, when your subs are hammered, burned and flabby?

It’s definitely an AGC. When the chosen threshold is reached, the gain is reduced. The only form of compression occurs when the input is fully saturated, which takes some serious doing. Regardless I’d suggest you do a double blind test on that perception. They’re not perfect, but I’ve measured one at various levels and it’s ruler flat bar a tiny wiggle of about 1 dB around the internal crossover frequency used to control the multi-band thresholds. If used sensibly, any distortion the op amps add should be far less noticeable than many other things in the chain - including your loudspeakers.

There are more transparent units out there, like the upper tier of the DateQ SPL range, but those get spendy very quickly.

Perhaps also use the possibly you can hear it being inserted as a cue to verify your gain structure throughout. Pro tip: you need to read some spec sheets or take measurements for that! It’s very, very often overlooked and as a result systems are sitting in or close to the noise floor or limit of components in the chain.

Check the ‘5 minute gain structure’ video by Pat Brown of SynAudCon on YouTube for a quick crash course.

I don’t have any experience with the dBMark XCA stuff but you shouldn’t be able to ‘hear’ an AGC, unless it’s not an AGC. It should work no different to you turning the channel gain knob up or down.

However this all just makes me think you should invest in the right tool for the job - open architecture install DSP with zoning and the like, plus the training or a tech to code it to your needs. No knobs or buttons to poke unless you choose to add them then too. Trust me, having many installs under our belts - if there’s anything to fiddle with by ‘someone’s mate’, it will be fiddled with eventually.

Earplug wrote: IIRC, member      RC1 Sound System was developing something. Here:- https://forum.speakerplans.com/dj-sound-system-volume-levellers_topic101739_page1.html

That’s the Leveliza already discussed. It’s not a protection device per se. Very useful if there’s no tech on site, or to allow one to have a break, but it won’t save the kit from being melted.

So I've actually got a Drawmer SP2120 In between the DJ mixer and the DBMark XCA but I prefer it not in the signal chain, I can hear the difference... plus it's another point of possible failure.

The Leveliza is great for keeping things to a perceived volume level. Still, it is not a limiter nor a true automatic gain control like the Drawmer SP2120, Formula Sound AVC2, Outline SPL Control Plus, etc.

Think of it more like someone riding the fader, based on the 'full-range level of the system you set:
https://www.waves.com/plugins/vocal-rider#achieving-perfect-vocal-levels-with-vocal-rider

Most importantly, it doesn't really track the bass. If someone kills the mids and highs of the mixer, then cranks the hell out of it, your subs will still be ramming into the limiter of your DSP.

In the before times, we were one of the first adopters of the Leveliza and found them best on gigs to allow for single engineer stages to have relaxed changeovers, toilet breaks and the like. The prototype install version we had made with a tamper-proof cover instead of knobs did the same trick for a three-floor nightclub that has a single tech on site. No more wondering 'is upstairs being hooned?!' when you're stuck in the booth of the basement.

You get the best results for an unattended playback install by using both of those types of toys together or coding your own in something that's open architecture like a BLU London or Xilica Solaro.

I'd suggest you do that in steps anyway because it'll benefit new subs too if you make them.

Port shape optimisation is the subject of lots of research lately. I shared some links to papers in another thread. Just guessing won't necessarily give better results than a straight slot, and could end up worse!

It's also worth noting that Hornresp doesn't include nonlinear behaviour in the modelling as far as I'm aware. You'd want to use large-signal data like the Klippel vibration file for the driver in Akabak3 to see what happens at large signal levels. Or just cut some wood, and get some drivers and port shapes cut to audition.

Sub measurements are a funny thing though, so if you're going down that route make sure you have a massive car park or field to hand. Ground-plane, nearest boundary 7m+ away, mic 10m from the average acoustic centre (not the grille!) of the cabinet.




Edited by toastyghost - 11 June 2021 at 10:10am

The original poster said:

"One of the big factors in wanting to upgrade is the PD186 are getting a bit hot and flabby/higher impedance/power compression degraded towards the end of the night if we aren't onsite and DJs have smacking the limiter straight from open doors."

Rather than spending thousands of pounds on new speaker drivers that you don't need, why not employ a sound engineer to manage the event for the night to "stop the DJ's smacking the limiters from open doors".

If you think that the sound has been degraded by the end of the night, what about peoples hearing?

If you run a sound system you should be in control...not a load of idiots (DJs???) who obviously havent got a clue.