Subwoofer Placement--delay necessary?

twinspindj

Hello Gadget and Dra, Happy New Year to you and the others who consistently provide help to all who seek your advice.

Recently, I purchased only a single Yorkville Elite SL801PB 18" subwoofer to go with the two Yorkville NX 750PB 2-way mains.

I have not yet used them at any event. However, I did check the sub out with the two 750's; x (main) - (sub) x (main) setup ("x-x"). Unfortunately, it was in my garage pointed to the opening. Normally, I use an 8' rectangular banquet table...speaker on either end of table with subwoofer centered in front of table. Because the sub was equal distant from mains (old setup with Yorki 750s and Yorki LS700PB [double 10" sub]) there didn't appear to be the need for any delay. Of course "what do I know about delay...nothing" but it sounded OK to me.

Now that I have the larger 18" sub and the energy pressure that is emitted from the rear, I don't dare position it in front of the DJ table as in the previously used setup. Keep in mind that I only have (1) LS 18" subwoofer (1500w).

What would be the preferred position for the 18" sub? I would guess that either the left or right side of the DJ table w/Pole mounted main and the other main spkr on stand. Ultimately, I will get another 18" sub LS801PB for the system and put subs w/pole mounted mains on each end of table. Since I'm not there yet, will I need to use the delay feature in the DRPA? If so, how and what setting? :?

Keep in mind I have diminished tech knowledge with regard to the DRPA. :oops:

Dennis

Since the delay would be used for time alignment between the sub and the mid/hi speakers, it would be a bugger to time align one sub to two mid/hi speakers in two different locations unless the sub was centered between them.

Dennis

twinspindj

Dennis, thanks.

So I've made a mistake by purchasing only one 18" subwoofer? :x

I suppose an option would be to move the DJ table to one side or the other of the "Spkr - sub - Spkr" setup, so the sub will be equidistant from the speakers? Or, move the DJ station farther back from the setup so the "sound pressure" is minimized to some degree? Somebody say "ear plugs?" :roll:

Dennis

No, you didn't make a mistake purchasing one sub.

What is the downside of the sub being close to your table? Do you use vinyl that the sub can cause to feedback?

Dennis

Gadget

No, A simple building block system is one way to look at it...If you place the sub under one side of the mains that means that the sub is mono and omnidirectional, and needs only to be aligned with the speaker it is matched with...IF you had placed the sub in a corner...to take advantage of corner loading the free gain that affords...as Dennis points out you would have two different path lengths in that scenario, you won't have with a sub right under one of the tops...

So, if the subs have a delayed sound output like a horn loaded sub (yours is a "rear loaded" front firing sub and not horn loaded per-say) like the UCS1P, then you would need to delay the tops to allow the sound time to get out of the horn loaded sub. That is however not the case here, and the DRPA+ doesn't have enough delay to really match a horn loaded sub, much less a remoted sub like the corner loading scenario...

If you do get another sub, your best bet is STILL going to be to have them both in one location under one of the tops and in a mono block. This will eliminate comb filtering from causing sonic chaos in the room...(if your unfamiliar with comb filtering you should check it out...) and here is a great tool for visualization of this affect:
http://webphysics.davidson.edu/Applets/ ... fault.html
take the two red dots (subs) and place them on either side of an imaginary stage like you would when setting up for a show...note the finger like sound waves.... the fingers are sound, and the black areas are those that the sound is far less audible...

Now take one of the red dots and place it ON TOP of the other and see that the waves are now strong all around the room.

Gadget

Dennis

Gadget, I hate it when your right so I'm going to say you are almost right. The sub has to align with both mid/hi's or you will have a mess somewhere. After doing a sketch and measuring, the sub (positioned under one mid/hi) will align with both tops at a center point between the tops (at any distance from the stage). Since you can align to only one point in space, center will do even though its not perfect. The two tops will have to be at the same elevation.

Dennis

twinspindj

Gadget, thanks for the additional instruction. I'm also using a DRPA not a +.

Dennis, I do appreciate your taking time to respond, too. To answer your question, No, I'm not using turntables. However, the sound vibrates quite a bit from behind the sub and I will be standing behind the table and the sub will be in front of the table (centered).
I tested the sound without the table and stood behind the sub and felt the pressure.

Gadget, thank you for the visual aid. I understand what you are saying. I am running the system 2-way w/mono sub.

So the best option when using either a single sub or double subs is centered in front of table or "stacked" if using double subs?

And, with a single sub on either side of table, w/2-way either pole-mounted or speaker stand, will work too?

And, with a double sub setup, one left and one right of table w/pole mounted 2-way spkr with a 2-way w/mono sub setup, would also work just fine?

The red dots when placed one on top of the other really strengthend the sound waves throughout the entire room. If the "stack" were on either side of the table, that would work too, but the waves wouldn't be as strong throughout the room?

And, a sub w/ pole mounted speaker on left and right side of DJ table would also work? Would the DRPA setup then be "DJ Setup stereo" or "2-way w/ mono sub?"

Gadget

Agreed Dennis, but with the fact that the DRPA has only 10ms of delay...and with a measured propagation 7.5ms delay from tops to subs in an LR24 2 way setup in the DRPA... even if he was SITTING on the subs with the speakers CLOSE on either side... he would STILL not have enough delay to properly do the job...SO, that said, do you not agree that the lesser of the evils here is to have at least ONE side aligned properly? What with the rule of thumb less than 4 feet or greater than 50 feet(rounded off for simplicities sake) for sub separation... few of us can do over 50 feet on the stages we work with...I personally have had my best success with this configuration... 2 subs stacked with a tops sitting on it and the other top on a tri-pod @ the same height as the other...

Twinspindj... I agree.. I cannot set up behind my subs... it's bad enough with them on one side or the other...however if you look at the position carefully... with proper setup position you can minimize the affect...

I do NOT place a sub per side unless there is NO OTHER WAY...

G

twinspindj

DARN! I messed up somehow and lost my post. Have to do it all over again. I'll be brief...yeah, right.

Thanks Gadget for being sympathetic toward standing behind the sub. Dennis must be younger than us old buzzards...LOL...no slam intended.

I will try the single sub w/ spkr on tripod next to it and the other main on the opposite side of table, using "2-way w/mono sub."

When I do acquire a sister sub I will place one on each side with pole mounted Main above them. Would I use the same "2-way w/mono sub" setting? OR...DJ setup stereo?

I doubt I would stack the double subs on one side...I'm afraid the 137 lb. sub would be way to heavy and I doubt the venue has a mini-fork lift...LOL! I'm my own roadie, too.

Thanks guys. It was not my intent to cause disagreement between you two, but each of you have your own preferred method of setting up your equipment.

Agan, many thanks...and I'll be back after my next gig with the new setup to explain how it sounded.

Dennis

If you didn't cause disagreement between me and Gadget, we would find something else to disagree about. And I don't know how old you are but me and Gadget are the same age...I just like standing behind subs.

Dennis

twinspindj

:P Glad to see you and Gadget are on level ground, age-wise. I'm older but definitely not as wise and experienced in the field of sound technology as the two of you.

Maybe I should find a bullet-proof vest to replace the tux vest I now wear

Gadget

I think Dennis and I sparred from his first post but we remain friends because we learn from each other... The one axiom you cannot argue with is "the more you learn... the less you know! I know for certain I don't know everything...but if I don't know something... I know how to find out...Many time I have searched the web emailed Mikey, Dennis or a number of other luminaries in the biz.. to find out everything I can so I can come back here and pass on that knowledge.
be well
G

twinspindj

Good morning Mr. Gadget...

Finally, I will be able to use the new Yorkville LS 801PB sub (1500 watt)...in a couple of weeks. The setup will be 2-Yorkville NX750PB (750 watt ea) and the 801PB.

This is a volunteer event, "Walk to Defeat ALS." The issue is best positioning for this setup. First, I know that I am grossly underpowered for this event...but it is NOT a dance, only background music (Top-40, Oldies, etc. that appeal to all ages) and PA for the Opening and Closing Ceremones of the event.

I will be setup on a very large (covered) cement stage. Can you picture ampatheater....cement area in front where people could dance and then a gradually sloped area (grassy hill) the rest of the way.

My idea of the setup would be "X.........sub..........X" @ 2-way w/mono sub setting.

The first question:
[Obviously, I will be centered on the width of the stage and the speakers/sub approximately 8 -10 feet from the front edge.]

What distance between sub and "X" would work best? I was thinking of 20-ft per side. All will be in the same line. I could go 40-ft per side, but then I'm not a band with mega sound system.

However, I could place the 801 sub w/Main setting on top of it and the other Main on Spker Stand (same height as sub/main). What distance between speakers would work best?

Second Question:

What DRPA settings would most likely work for this speaker arrangement? (The NX 750P does have a "60" and "100" db button that can be depressed when using it with a subwoofer. I have been pushing button IN for 100 when using subwoofer; leaving it "out" when using them as stand alone speakers.

Next to Last Question: The back of 801P has several XLR inputs. There is a Mono Blend Input XLR, as well as Input/Output. Also, a couple of dials: 801P Level dial, Shape dial, and HI Freq Rolloff dial. Your help with these settings, too, please. :oops:

Last Question: If I were to connect my smaller powered RCF Mains (12") to the Yorkville Mains, how can I keep from blowing the smaller speakers? Each speaker has it's own Level Control knob. On the other hand, I could use the smaller RCF mains as the PA, connect them to each other and input the Microphone XLR direct to the speaker. Only down side to that is that I would be unable to raise/lower the Volume during the opening and closing ceremony without physically adjusting the knob on each speaker manually...look kind of odd with me standing behind the system and then moving to each speaker to adjust the volume while the Official is talking. BUT, I could connect the RCF mains to my mini-mixer and control the volume from there.

Thanks in advance for any help that you may choose to provide.

Gadget

Well, the absolute best thing for coverage and sonic purity, put the tops together side by side using the coverage angle of the horns to determine the splay...with the subs under (think point source). Next, sub in the middle with less than 10 feet from sub to speaker so you might have enough delay to do some alignment, and then one top over one sub on one side and the single top on the other.. Dennis?

What DRPA settings would most likely work for this speaker arrangement? (The NX 750P does have a "60" and "100" db button that can be depressed when using it with a subwoofer. I have been pushing button IN for 100 when using subwoofer; leaving it "out" when using them as stand alone speakers.

Here I have to assume you mean 60HZ and 100HZ??? yes, with sub set to 100 hz, and use the DRPA to set the xovers.

Set up a 2X3 use the hi outs for the tops or just one if you want to run mono 2 way and daisy chain .. but really, if you set all the pan controls on the mixer to center (unless you use a DJ mixer that doesn't have pan...)you have an effectively mono mix... Use the left mono out for the sub. You can let the sub be it's own HPF and limiter, so set the HF rolloff knob as hi as it will go.. as in toward 200 hz as opposed to toward -20- hz. we will let the DRPA set the xover point here.

Set the xover @ 80-90 hz to avoid the built in xover point on the tops. As for the blend knob I don't know what that does so you might want to experiment with it, but I suspect you could accomplish the same thing (and much much more).

Last Question: If I were to connect my smaller powered RCF Mains (12") to the Yorkville Mains, how can I keep from blowing the smaller speakers? Each speaker has it's own Level Control knob. On the other hand, I could use the smaller RCF mains as the PA, connect them to each other and input the Microphone XLR direct to the speaker. Only down side to that is that I would be unable to raise/lower the Volume during the opening and closing ceremony without physically adjusting the knob on each speaker manually...look kind of odd with me standing behind the system and then moving to each speaker to adjust the volume while the Official is talking. BUT, I could connect the RCF mains to my mini-mixer and control the volume from there.

Run the system 2x6 use the left channel and put the left channel in to the Yorkvilles, use the hi and mid outs for instance for the hi, and sub outs, simply set the mid channel up like you would the lo outs (HPF 30 hz BW18, LPF 80-90hz LR24) then send the right channel to the RCF using the right HI out and set a bandpass filter (simply lower the HPF to 80-90hz as you did the NX tops. this way you can control the Yorkies with the left channel and the RCF with the right...(again unless your using a DJ mixer without pan or left right out controls...)

Gadget

twinspindj

Gadget...thanks for speedy reply.

I am using DJ Mixer...left and right outputs...no panning capability.

I didn't follow the 2x6 setup.

I'm thinking of using 10' left and 10' right of sub...making a front line of 20'. Since I am up in the air well above the crowd, would I need to put the Yorkie Mains on spkr stands? If so, then at the lowest stand setting?

Then, I will position one RCF Top to left and right of each Yorkie...and run this as only PA. I have a small mini-mixer about 6" x 4" that I can plug either a wireless or cord microphone. I can control volume from my DJ station. They don't need a mic stand for opening/closing remarks.

Because I'm still not learned with setting the crossover freqs, etc. on the DRPA, I'm trying to accomplish task without that assistance. That's why it is easier for me to run 2-way w/ mono sub. I realize that I may not be using the DRPA to the fullest, but so far it sounds good.

Have faith...I will learn...it's only a matter of time. :roll:

Dennis

Gadget wrote:

Well, the absolute best thing for coverage and sonic purity, put the tops together side by side using the coverage angle of the horns to determine the splay...with the subs under (think point source). Next, sub in the middle with less than 10 feet from sub to speaker so you might have enough delay to do some alignment, and then one top over one sub on one side and the single top on the other.. Dennis?

I like twinspindj's idea. With the sub centered, if you were to actually do a sub alignment it wouldn't matter if the mains were 10' or 30' from the sub...the measurement mic would be 50' to 75' in front of the stage and the variation in sub/main distance would be mere inches at the measurement mic position. 10ms is plenty...remember, you aren't measuring the full distance of main or sub to mic position but rather the difference between the two.

Twinspin, this mic position does not refer to any auto function of the DRPA but rather for a dual FFT program that would be necessary to correctly do an alignment. My post was FYI only.

Dennis

twinspindj

Dennis, thanks for the kind words. I'm trying to keep it simple until I can find someone to actually sit down with me and the DRPA and show me how to do the crossover settings, ect.

10ms is plenty...remember, you aren't measuring the full distance of main or sub to mic position but rather the difference between the two.

I have a measurement mic but I have never used it (Behringer ECM 8000). Are you advocating that I need to use the maximum dealay for mono sub to mains?

Please forgive me because I am a nervous novice when it comes the DRPA.

Gadget

Ok,
the thing is the DRPA has the capability to run 2 channels separately...so consider the left channel as channel 1 and the right channel as channel 2, so, from the mixer, pull the right channel fader down and you have only signal going to the left channel correct? So if we hook the left output of the mixer to the left channel of the DRPA, we can then say we have mono capability..

The DRPA can be set up stereo, and dual mono.. in dual mono you can auto eq each side separately, which comes in handy for a number of things.. like an uneven room, or mono FOH and one monitor channel, or in your case, left channel for the Yorkvilles and Right channel for the RCF's and there you have the ability to use the left fader and left DRPA channels to control the Yorkies, and the right fader and right DRPA channel to control the RCF speakers.

Now, it is important to overlap coverage as little as possible...What about setting up the yorkies as a center cluster, and using the RCF's as an outer coverage? or using the left right config you spoke of and using the RCF's as outfills beyond the coverage of the yorks. As Dennis said the measurement and delay would be very difficult for you to do...

You can set the DRPA up as a 6 speaker controller, each can be set up to reproduce some or all of the audio spectrum by simply manipulating the HPF and the LPF (high pass filter.. the lowest you want the speakers to go, and the LPF, the highest you want a speaker to go). The High outs on the DRPA do not have LPF's, but the mid and low do, the High outs have 3 peq's (parametric) the mid and low have 2 peq's.

In this way you can set up,the left channel of the DRPA as a 2 way mono system to control the Yorkvilles, and set up the right channel control the RCF's

In the Wizard:
1. Set up a 2x6 all custom setup (don't worry about any of the presets, they are useless here so just enter custom)
2. load the preset (press the encoder button) this is like a "home" button, pressing it will bring you back to the preset you are working with.
3. press the xover button
a. using the <prev next> buttons and the encoder select the High outputs HPF (this is again all you have to work with) set it at (lets use 90 hz for this example) 90hz, LR24.
b. select the LPF of the mid band, set it AT 90HZ LR24.
c. set the HPF for the mid out at 30hz BW18.
that now gives the left high outs from 90hz on up to out (whatever the speaker can do), and the mid outs will then be set up reproduce 30hz - 90hz and this would then feed the yorkville speakers.
d. next select the Low out on the xover and select the HPF this can be set to the same frequency as the Yorkville tops @ 90 hz LR24 the LPF can be set to out or anything above 15khz with and LR6 slope if you wish. This will then allow the right low output to reproduce 90hz on up for the RCF's

Gadget

Dra

Let's make a few assumptions.
The NX750's "may" be processed.
The LS801PB definately are.
If we assume that Yorkville intended you to pole mount a Yorkville speaker on top of the sub, AND that the unpowered version of the sub needs (can't remember exactly), but 5-10ms of delay provided by the Yorkville processor. Then the powered one will too. Sooo... the LS801PB will have whatever the correct amount (pole mounted) of delay. So at least all of the DRPA+'s delay will be usefull for actual separation issues.
Hope that made sense.

DRA

twinspindj

Gadget...you made the light bulb come on :idea: ! :P I think I understand the concept and path you are leading me down. I will have to digest all that you have said and report back.

:roll: Dra...thank you, too. If I may try to paraphrase what you are saying: Put the Yorkville on the Pole mount (if I have one and if I don't then put a Speaker stand directly beside it?) BECAUSE the Yorkie powered sub and powered main are internally crossed over for delay? :?

Gadget. Here is where we may have a problem. The mixer I am using and I know you're going to shreek is a Numark CD-MixII whch has only one Master fader that controls left and right channels simueltaneously, or in your words, "Channel 1 and Channel 2."

I also have a Numark DM1295 Mixer...same issue as the CD-MixII...only one master fader. But, I do have an OLD, get this, Radio Shack Mixer that has a Left Channel and Right Channel Volume Control, but all of the connections are RCA vs. XLR.
Is this what you are talking about Left Channel Volume (to Yorkville mains and sub) and Right Channel Volume (to RCF's).
:roll: I don't even know if the radio shack still works. :P

Once again, you fellows are helping a "dumb, partially blind, and deaf" old fart. (Not really deaf or blind, but definitely ignorant of DRPA use). This will be one for the record books if you get me up and running! :shock:

Dennis

twinspindj wrote:

I have a measurement mic but I have never used it (Behringer ECM 8000). Are you advocating that I need to use the maximum dealay for mono sub to mains?.

NO! I am suggesting that the 10ms delay available with the DRPA is more than enough to align any configuration you could come up with as long as it stays in a straight line (x..sub..x or x......sub......x). Without the proper measurement equipment, you are probably better off not delaying the sub at all...you might do more damage than good. I was just trying to explain the concept.

Dennis

twinspindj

Dennis, I follow what you are saying. Thanks for the clarification. I always set my system in a line; Yorkville's on either side of 8-ft banquet table with the subwoofer in the middle.

twinspindj

....in your case, left channel for the Yorkvilles and Right channel for the RCF's and there you have the ability to use the left fader and left DRPA channels to control the Yorkies, and the right fader and right DRPA channel to control the RCF speakers.

Gadget, I don't have seprate cross fader for left out and right out, except for the OLD Radio Shack mixer w/ RCA input/outputs.

Please clarify. :?

Gadget

Ok, without the independent L/R you could still do the same, it's just not as easy...You can however use the crossover gain control on the DRPA to turn the RCF's up and down..If you have the DRPA+ you also have the individual output on off switches.
Gadget

twinspindj

Thanks for clarification. I will try to locate the OLD Radio Shack and see if it still works? :roll: It probably does, it's just old. I have rca to XLR adpters or TRS to RCA adapters, so I will be able to hook up the RS to the DRPA.

I'll be back :!:

Gadget

sorry but the old Radio Shack probably won't work.. just use the info we gave already ..
G

twinspindj

:P :roll: Gadget, Dennis and others who speculated on how to position the subwoofer for maximum affect.

Saturday, 4-10-10, I finally got to use my new Yorkville LS801P subwoofer with the Yorkville NX750P's.

Setup on stage that was probably 8+ feet high that was made of cement It was pretty much an open-air affect with 3-sides open (front, left and right). I blieve the entire front was about 200 ft wide.

I set up the subwoofer at center stage about 15 feet from front edge. Placed subwoofer in the middle and then 20' left and 20' right of subwoofer, in a direct line: x - x (x=sub), y=Mains.

The RCF Mains were placed beside each Yorkville Speaker to the outside, about 5'.

I used the 2-way with mono sub setting for the DRPA. Did not set any high or low pass filters. I let the speakers do whatever they could do. The RCF's were plugged into the Yorkville (output) XLR so the signal would pass through to each RCF main.

At a reasonable sound level I tweaked the York Mains and Subwoofer. Next, while the system was playing I turned on the RCF Mains and adjusted the sound level so that both the York and RCF mains were at the same loudness.

I can tell you that that 18" powered subwoofer did its job very well. I had the DJ table at least 8' behind the subwoofer and I could heat it loud and clear.

I use the wireless mic and had no feedback issues.

I was amazed at the amount of sound that the system was capable of producing. Didn't blow the smaller speakers either. I set the volume control at only so loud vs full open.

Have faith, I will learn to use the DRPA.

Gadget

Ya but you can't let the speakers do

I let the speakers do whatever they could do.

the interaction in the crossover will creates problems sonically.. with the RCF's run through the subs I assume the LPF was put to use on them.. :?
G

twinspindj

The RCF tops were connected to the Yorkville Top's "Output" connection, so they were getting the same signal.

Because there were no "boundaries or nodes" the sound was pretty good. In fact one of the local radio station DJs that was co-sponsoring the function came up after and complimented me on the sound system. I would take that as a good indication that the system did quite well as set up. Now, could it have sounded better? Yes, but I'm looking forward to working more diligently in learning the programs of the DriveRack PA.

Gadget

If you were to stand in one place you may or may not have noticed the problems, but if you move around, or are unlucky enough to be in the myriad sonic chaos locations... you WILL notice the problems...and the HF sound isn't the only frequency areas that will be affected by speaker locations... ESPECIALLY sub-woofers...if you split them one per side... well you will have cancellations, lobes and nulls and FINGERS of bass and regions of limited bass...and a power alley of varying size down the middle...
Gadget

Mikey

I have this theory about delays...if what is going into the system sounds really bad, use a delay. About 2 days will usually work. That way, if the musos really suck, the sound will try to get out after the system is safely in storage in your garage. No one will be harmed and your reputation will be intact.

This has been Mikey's mix public service announcement number 37.

Mikey