New DBX User

li_bassman

I have just bought a DriveRack PA. I have read a ton, all the posts, recomendations etc (I don' seem to be able to get to the auto eq white paper). I think I have read too much because I am really confused on what to do. I have our first gig coming up with our new PA and I do not want to wreck our sound.

I need some serious help on what to use as a starting point and what to look to tweak at a first gig in order to sound good.

The PA consists of the following:
2 S115IV powered by a Peavey PV 2600
1 TurboSound 18\" Sub powered by Mackie 1200i
Mackie CFX 16 Mixer (with a sub out)
1 DriveRack PA
1 DBX Compressor (for our \"dynamic\" singer's channel)
Delay effects rack

We are a good rock Band that has 4 singers, elecronic drums, conga drums (miked) 2 guitars (miked amps), KBs (2 stereo), and a bass (who doubles as the pseudo sound guy - that's me).

1) Should I use theAuto EQ - I have read many conflicting posts - some say it is great - other's said it kills the crossover, lows and high settings. Also should I use the flat EQ or can I use one of the other settings to liven up the mix?

2) If I make corrections which EQ should I make it to.

3) Should I put the rack in the insert loop on the mixer or use it after the mixer and utilize the crossover

4) If I use the DriveRack crossover (I think I should) should I use the 6-8 ms delay I have seen recomended.

5) What should my initial compressor and limiter settings be set to - i am looking to protect the system but not kill our dynamics.

6) What does the sub Harmonic module do - I know it does something to the low end - If I use it, the sub amp has a high filter at 30HZ - should I defeat this or leave it?

I have been playing with the unit but do not fully understand it and am willing to put in the time to learn. I just want ot make sure I do not blow the sound the first time we use the newly put together PA. Sorry if I got any terms confuse - I am new using more sophisticated equipment (we had been using a simple integrated PA with no subs before).

Thanks in advance,
Doug

Gadget

Hi
1. If you do, (and there is a chance you won't be able to if there are customers there) use a nearfield (CLOSE 6-8 feet) mike on 1 stack(the side with the sub) centered between the woofer and tweeter on the Yamaha. use the flat response. After the EQ finishes, manually zero the below 150 and above 700 hz. This is were you use your ears and a good CD to \"season the sound \" to taste, using the GEQ... If there is too little bass use the amp controls first if possible, then the GEQ...the kick is centered around 80hz 150 will beef up the lo mid bass...This is a very simplistic answer to a deep subject... but for now...

This presumes you have 'roughed the system in, which means you did a gain structure(see the back of the manual), balanced the sound between the subs and the tops. (but you read all that right?)

Don't be surprised if you can't use the auto EQ, then just do a custom setup in the wizard, ballance the sound roughly, do a gain structure, as above season to taste..

2.The GEQ for the time being... when you are more familiar with the GEQ's they can be a really great alternative...

3.Not sure I know what you mean... but XLR's out of the mixer 'main' outs to the DRPA XLR ins, use the 'hi' outs to the yamaha's amp, 'lo' outs to the subs amp... Use a linked stereo setup, with mono subs

4. If you use the Linkwitz Riley 24 DB / octave slope... we know this one delays the sound to the subs amp about 7.5 ms.. this is the crossover point you would need to set up in the crossover after you have done a wizard setup. You would delay the 'hi' outputs to do this...

5. Skip the comps (you have to select 1 or the other) the limiters are kind of tough to set up if you are doing sound from stage... use the meters and yellow lights above each channel to indicate when the limiters are active. If you set the limiters too low, it will squash the sound and limit the volume you can achieve. a ballance of these things is necessary... Select how hard you want the limiter to hit, then lower the threshold to just above the level you find comfortable for the band and room. this allows a little overshoot before the limiters hit... this also assumes you have sufficient headroom to allow for this... if you don't, set the limiter so it hits harder and sooner to prevent the amps clipping.

6. Skip the Sub harmonic module...

Here's the paper's location:
http://www.driverack.com/drug/attachmen ... rence1.doc

There really is a lot to know here, but its pretty easy to get it up and running... remember, where you are unfamiliar... less is more. That is to say you don't NEED to use all these features... the DRPA sounds good enough without even using most of the features to get you started...using just the xover... Oh, use 100 hz crossover to start with with a L/R 24 as the center point of the cross between the sub and tops...so the tops do 100 hz and up and the subs 100 hz and below... set the HPF (lowest point the subs can go @ 50hz @ L/R 24 or BW 18.

Good luck
keep us informed.
Gadget

li_bassman

Thanks so much for your reply - I understand jsut about everythig except the following:

4) Does this mean I need to set the delay for the hi's to 7.5 ms

5) do you have suggestions on what settings to use on the limiter as a start?

Also when do I know if I have a problem with phase - or is this something not to worry about at this point ...

Thanks again with all the help - it is really appreciated.

Doug

Gadget

Doug,

You can, add the delay... but only if you are using the \"Linkwitz Riley 24\" DB per octave(L/R 24) filter... this is the only one that has been measured at this point and as in any digital device it is called 'latency' and is the product of the processing necessary to create the changes to the sound...The difference however is subtle... the un-trained ear probably won't notice any real difference... its just us anal types that strive for perfection... If you are interesetd in this as a process, at the old site there is information on the process used to determine where the delay is best set, using test equipment, or even just your ears and a \"null\" in the sound when the inputs of one of the speakers (sub or top) are reversed. if you play a specific frequency, the frequency you set as the crossover point (we set 100 hz right?), when you sweep the delay you will hear a null (lack of sound) when the two signals cancel.

As for the limiter thing... Its really not a big deal to set up... you need to know what the maximum volume level you want, and that can be found on the output meters of your mixer. Lets say they read +3 when the system is sufficiently loud. Toggle the Dynamics on, select 'limiter' you will see a meter at the top of the display. this will display the amount of gain reduction as it goes below the thesehold... I would suggest starting with a value of 5 for the over easy and turn the limiter to 'ON'. now slowly lower the threshold till it starts reacting to the signal (on the meter for the limiter) going through the board ( the +3 peaks we were speaking of ) This should be somewhere around the +3 area we set as our goal. Once the meter is detecting the signal from the mixer, as we lower the threshold further the meter starts to go neegative and the yellow lights above the DRPA meters will begin to blink indicating limiting action.. the harde it hits the more reduction will be applied, and you will start to notice the 'gain' volume decreasing... this is too much reduction and should be backed off till the reduction just stops, now if you want to limit harder or softer you would do so with the 'over easy' setting. this sets how much overshoot will be allowed... just play around with it and you'll get the hang of it...

As for phase its a deal that can be easily checked with a battery on cone drivers... a + to plus and - to negative on a 9 volt should drive the cone out from the frame of the speaker... as for drivers (horn typpe and tweeters it is important to know if the drivers are wound so that a + sigal will yeild a plus action of the diaphram... there are phase checking devices out there that you can purchase if its important to you... and I have one such device. Crossovers also create phase shifts, but that isn't in the scope of this discussion...

Be well
Gadget

li_bassman

It makes much more sense now - thanks!!

Last question - should I control my overall volume level from the faders on the board or the amp volumes -

That is, should I look to send a \"0\" signal from my mixer into the Driverack and turn down the amp volumes if it is too loud (no worry of clipping). This way I would be sending a better quality signal to the amps.

or

Do I have the gain structure aligned and lower the master mixer faders to control the sound - thus the signal out may be below \"0\"?

Thanks again,
Doug

Gadget

Do I have the gain structure aligned and lower the master mixer faders to control the sound - thus the signal out may be below \"0\"?

Always stay with the gain structure and then use the master faders for control..

G[/quote]

Mike McNany

Gadget wrote:

4. If you use the Linkwitz Riley 24 DB / octave slope... we know this one delays the sound to the subs amp about 7.5 ms.. this is the crossover point you would need to set up in the crossover after you have done a wizard setup. You would delay the 'hi' outputs to do this...

Gadget

Gary,
This is the first I've heard (read) of this. The sub output using the LR24 DELAYS the sub output, compared to the tops, 7.5ms? That would mean with the 10ms delay available, I would NOT be able to actually use the factory suggested 5msec delay to my tops (Yorkville U15 over LS808). I would need 12.5ms of delay in the DRPA! Hmmmm?

Mike McNany

Gadget

Hi Mike,
Ya, sorry bout that... :oops: That figure comes from a much higher source than myself, 8) and was measured with SMAART. :idea:

That in and of itself makes the 260 the only source for my system. The LABsubs are a 10.5 ms pathlength, Its funny, I had used my ears and arrived at 18 ms :shock: and couldn't figure out why till I found out about the delay in the L/R24 in the DR.

All the Xovers types will eventually be measured and posted as time permits.

Be well
Gadget

li_bassman

ok - so i am a little confused with the last post - do i need to set my delay on the highs to 7.5 or higher?

Thanks

Gadget

Hmmm,

Not sure what makes you think anything is different, Mike just wasn't aware that the latency issue had been found,,, I have answered many post in the past, and mike has been around for a while. The 7.5 ms pertains only to the latency issue, If you place your mains farther back on the subs you wull need to consider that also... remember the DRPA onl;y has 10ms of total delay available... The 260 however has MILES worth of delay...
Gadget

li_bassman

I just want to make sure I am settign the crossover points correctly - I am using DR24 - i set the for the subs to 125hz (turbosound recommended) and the low cut for the high at 125hz.

There is a little \"overlap\" on the graph on the slope but it looks like there is a small gap on hte graph as well. I just want to make sure i have this right.

BTW - the PA is up and running and sounds great so far.

muzacmedia

HI Guys,
so if i am using a L/R 24DB slope on my main cluster and I have a full range for a fill in the same room should I add the same 7.5ms delay on that speaker to compensate for the latency issue.

Gadget

Hi,
No, at least as far as I can tell from your post...the 'Group Delay' is 1.63ms, but if your not using subs, then there is no need to delay anything (the actual 7.44 ms). The L/R 24 delays the \"sub/lo outputs in a 2x3/2x4 xover. The test setup crossed out @ 121.4 hz @ L/R 24, with an 18 db/ oct. BW, @ 28.7hz HPF.

gadget

muzacmedia

HI Gadget,
I'm sorry, the question I was asking I guest should have been posted somewhere else. The DRPA cannot do what I am asking. On the DR260 running a 2x3 or 2x4 with another output HPF at about 60hz and LPF out (hope I am explaining this correct) :?

Gadget

Speaker delay has a lot to do with

1. speaker position with reguard to each other(are they far apart as in subs under the stage and the mains flown...)

2. alignment delay... how long is the distance from the speaker to the front of the cabinet (as in a horn loaded sub that has a 10 foot laberynth for the sound to get out of the cabinet)Or the distance from the bottom of the woofer on a front loaded top cab, to the diaphram of the horn driver.

3. alignment to backline, so the loudest thing on stage comes out @ the same time as the FOH speakers.

4. the correction for the delay the crossover creates. (if there are \"tops\" and \"subs\" in the case of the 7.44ms created in the Linkwitz Riley \"24\" db/oct. filter only)

So you could have multiple delay times for multiple speakers, and the 260 could do it all and more (it has MILES worth of delay)

So if you have subs... yes you should compensate for the delay... if you have horn subs, Yes, you should compensate for their path-length also, and if the speakers are divergent (big difference in position in the room) , yes, that should also be taken into consideration...even if there is only a few inches between the bottom of the woofer cone and the diaphram of the horn, and you are biamping, you should correct for this...Thats what \"alignment delay\" is for.
gadget

li_bassman

i think my question got lost in the thread ....

/********************/

I just want to make sure I am settign the crossover points correctly - I am using DR24 - i set the for the subs to 125hz (turbosound recommended) and the low cut for the high at 125hz.

There is a little \"overlap\" on the graph on the slope but it looks like there is a small gap on hte graph as well. I just want to make sure i have this right.

BTW - the PA is up and running and sounds great so far.

Gadget

Sorry, thouught we were through...

Yes If thats what you are going to cross at... I usually like to go lower unless the tops can't(or my power is limited), the subs sound less honky.
Its tough to beat manufacturer specs, but when your not using a specific system, there is room for experimentation.

As for the crossover slope, thats exactly what it is.. a slope... and where two slopes that are going oposite directions meet, there will be overlap. the steeper the slope the less the interaction at the overlap area. I assume you ment L/R 24 not DR24.

Gadget

li_bassman

perfect and thanks!!

li_bassman

We have been gigging out and the driverack has been working great. We have been utilizing the autoEq and it is doing a far superior job than I could do manually. Thanks for all the help to get us to this point.

We have a larger outdoor gig coming up and we are looking at adding some speakers for this one gig only.

Currently we run a 2x3 setup with:
peavey 2600 amp powering 2 yamaha SVIVs
mackie 1400 powering 1 turbosound sub


I want to add:
2 more yamaha speakers (powered by the same amp - there should be enough power for them)
one more sub and amp

Here is my quesiton -
I would like to add the speakers in parallel and the sub by using the line out from one amp into the other . I would leave the driverack settings the same. I want to take this approach to keep everything simple since I have a good grasp on how the system now works.

Will this be ok with the Driverack and will the autoEq still work?