Bypass Driverack PA?
dentcorn
Posts: 7
As a new user of a DRPA, I was wondering if there was any way you could bypass the thing - without too much fuss - to do some A-B comparisons to hear how much it was actually helping the sound. Thanks a lot
Mackie CFX-12
Mackie SA-1520z mains
Mackie SRM-450 mon
AkG D-5
Akg c-1000s
AKG C-2000
Driverack PA
Mackie CFX-12
Mackie SA-1520z mains
Mackie SRM-450 mon
AkG D-5
Akg c-1000s
AKG C-2000
Driverack PA
0
Comments
I know in the DR260 you can turn-off all of the prcessors (GEQ, AFS, PEQ, Limiters, Delay, etc., etc.)... I assume you can do the same in the DRPA... I guess you would still want your crossover to work?...
Kevin
DRA
DRA
I remember when I first heard the Driverack and what a HUGE difference it made...Can you believe I was using a BBE ...\"hey man it's like taking the pillows off the speakers!\"
Have a happy holiday!
G
PS anybody use the new AKG D5, just bought a couple and they seem to give quite a bit more GBF.
DRA
I have been using sort of a modified method of this setup for doing the RTA and it has helped our sound immensely. We do acapella barbershop, choir, etc to a crowd of about 700 and after the show I heard the comment \"did you get a new PA?'...so must be doing something right. Sound was much cleaner and tighter. Am looking to use this method next weekend to see if things can be improved further.
Explain something to me: The posters over at PSW (ProSound Web) sure do not like auto eq and/or feedback detection at all. As far as it goes, it seems to me the AFS would set filters more precisely, with less \"Q', than a 31 band GEQ could with even a very trained set of ears. And it seems that the AFS would cut out less of the musical spectrum than a manual GEQ run. As far as the auto-EQ/RTA function, the sound I obtained was probably better than I could do setting a 31 band by hand, because I am new to this and I have no idea which bands affect what, etc...that will come in the future I hope. All I know is I liked what I heard and apparently others did too.
All sound is subjective in some way: why would you choose a Martin guitar over a Yamaha or a Steinway over an Acrosonic?
Another thought: I will use the \"indoor method\" on my system and this thought does not negate that but...this method is setup to negate the effects of the room, air etc on the auto tune process (next post)
Anyways my idea was that when the sound engineer tunes the system from the mix position, he is hearing the effects of the room, etc...if he moves 10 ft from his mix position the sound is different...of course we try to minimize this...but it sounds like a lot of these guys are just being snobby or are just Luddites unwlling to learn some new, and maybe BETTER technology.
Any comments?
The purpose of the AFS is, duh, feedback elimination. The system should be as flat as possible to start. For an all vocal gig like yours, if you must chose between sonic purity and no feedback, guess which wins? While all things in sound are related, you must sometimes pick the things that in the end matter most for the gig. Yes, considering that each 31 band filter is 1/3 of an octive and even the lowest AFS setting (speech) is 1/5th octive, then up to 1/80th at music-high it make sense to go with the AFS over the EQ. Also the EQ is fixed on ISO centers and the AFS will zero in on the exact frequency. So use it.
DRA
By the the way what are the auto eq preset curves derived from (a, b, c, d)?
Which one should i use? (Probably the flat one...)
And for that matter, how much precision do I want out of the AFS setting? I have been using the highest setting, thinking that woud be the least intrusive.
Also I am setting all except two of the filters to \"fixed\". I seem to have a hard time getting it to catch feedback in the live mode. I am guessing that this is because somewhere in the gain structure chain I do no have it \"seeing\" enough signal (???).
Thank you again for all your help.
You have come to the right place for any information that is particular to the DriveRack!...
I have only used the DR260 so allot the things I suggest may not apply... I have also been waiting for a good excuse to do a write-up on some nifty procedures (with my spin of course) provided by Dra and Gadget...:)
I'm assuming that you have the DBX RTA microphone or one of equal or greater quality... If you have separate subs and tops I recommend that you check the time alignment and phasing before performing the AutoEq... This can be done with a signal generator, the DriveRack, and the RTA mic... If you don't have a signal generator you can download one from the web and use your laptop...
For both of the following procedures aim your RTA mic directly between your subs and tops... Only enable one side of your system (mute either the left or right)... Generate a tone at normal listening level that's directly in the center of the crossover point between your subs and tops... For example: if the HPF on your subs is 105Hz and your LPF on your tops is 109Hz then your tone should be set at 107Hz...
Before checking phase put your tops right beside your subs if possible... You can either use your ears or enable the live RTA on the DriveRack (if applicable) to get a visual indication of the tone... Sweep the phase (if applicable) on your subs until the tone is at its loudest peak... IMHO...your subs and tops will be "in phase" when the tone is loudest...
Before checking the time alignment put your speakers back to their normal positions and repeat the process... When checking alignment you can either set your subs at 180 degrees out-of-phase and sweep the delay until the tone is at its quietest or keep your subs in-phase and sweep the delay until the tone is loudest... Personally,...I have found that either method yields about the same delay...
I recommend using the flat response curve... When you perform the Auto-EQ only enable one side of your system (mute either the left or right)... Lay the RTA microphone directly on the floor about 2/3rds back from the front of the venue listening area and pointed towards the active side... Increase the pink noise volume to your normal venue listening level and use the fast mode... Once it has completed set everything (in the GEQ) from 0-100Hz flat (at 0dB) and adjust everything from 7KHz and above to suite your taste...
Always place your speakers in front of your microphones (closer to the audience), and place your wedges in front of your microphone stands aiming them directly toward the vocalist... This should help eliminate any direct feedback with exception to reverberant surfaces…
For surgical precision you can ring-out the system and use either the notch filter or PEQ's for additional suppression... Enable the AFS, clear the live filters, and turn-off the filter lift... This will allow the AFS identify the problem frequencies... If using the PEQs only enable one channel at time... Turn-up the gain, move your microphone around the stage, and ring-out the system... Every time the system rings check the AFS live filter for the frequency and set your notch filter or PEQ accordingly... Clear the AFS live filter and repeat the process until your satisfied... Once this is done I would keep the AFS enabled, all filters live, lift after 5 seconds, and music high... You may also want to read page 20 of this thread for additional information provided by Gadget...
Do not use the "system" compressor in the DriveRack... This compressor will allow for increased energy to reach your amplifiers and loudspeakers, and will increase the possibility of feedback...
The first thing you should do above all else is check your gain structure... The procedure is provided in the body ofthis thread...
Anyways,...I see it as my job here to create as much confusion and caos as possible...
Cheers,
Kevin
Well, Dra has already told you that the 1/3 octave EQ is inadequate to equalize the \"system\" With respect to the room. The Feedback eliminator in this case is usable, but far from perfect. The Auto EQ is pretty much useless as a room treatment. ESPECIALLY in the under 170hz and above 700hz frequencies. Room modes, and nulls will plague your sound in the low end. This is because of standing waves that can cause couplings and cancellations. The higher the frequency the more problematic the reflected cancellations are. (those frequencies that arrive at the mic 180-degrees out of phase will cancel. However, move the mic a couple inches and that cancellation is no longer a problem... but a new one is) These will limit the volume you can run and give you fits trying to find them. 8)
The Auto EQ presets are depicted in the manual, and represent some typical presets that \"emphasizes\" and \"de-emphasize\" different frequencies. The \"A\" curve has a boost in the bass and high end, and a cut in the midrange...~
I flattened the system using the \"New indoor method\" I had the crossover set, the alignment delay dialed in, the PEQ's set for CD horn compensation, and established the \"flat\" preset. I copied that to other locations and compared the way the Auto EQ from a specific room compared to the stored flat response.
The Auto EQ tries to get equal loudness from the 28 bands at it's disposal. In the indoor method which is also available here:
http://www.dbxpro.com/forum/viewtopic.php?t=953
which is in the FAQ, WELCOME READ ME FIRST post on this site... The problems associated with trying to use an RTA based system to tune a system in a room are as you said, that you take a measurement in one spot, say the mix position, and move a foot and it's different. What we profess here is to use the Auto EQ to flatten the system to get equal energy from all frequencies in your system. Then save that as a preset. You can then Auto eq a room and compare the different passes and see what the room is doing to the sound. When you become proficient enough you can make informed decisions on things to do in order to minimize these affects.
As Kevin points out phase alignment and gain structure are important facets of the tuning process.
Gadget
Second. Dentcorn, don't go crazy trying to find some of the features that K talks about. They don't exist on the DRPA. The more you look, the better though.
Third. Kevin, some pretty cool insight (incite) there. And, thanks for the tone generator link.
DRA
As my handle suggests I am a farmer. One thing I have learned from adjusting combines (and there is a lot of stuff to adjust on them) is to change ONE THING AT A TIME. If that doesn't fix the problem (i.e. too much trash mixed in with the clean grain), go back and reset that variable to where it was (i.e. open the chaffer back up) and try something else (bring the RPM's up on the cleaning fan). Trying to adjust too many things at once results in much confusion. I try to apply the same logic to SR stuff. By the way,farmers are the fastest adopters of etch around, I believe. Not me, but about half my neighbors have GPS auto-steer tractors...and other tech wonders.
But I digress.
One thing the Mackie SA1520's are active biamped systems, so you don't need to mess around with crossover points, time alignments, etc. It is all built in. Any comments on these speakers? I liked them better than the JBL EON G2's I auditioned.
Thanks again Kevin, Gadget, dra and others for all your help.