BillFitzmaurice.info

Hi!
I am wondering about pros and cons, choosing setup for a venue..
It is about 5m. wide, 12m. long and with a height of 3 meters. (About 16x40×10 feet?)
The floor right now is gravel with thick textile carpets on, walls are plaster or wood.

The ceiling is now planks with plastic foil on and glass fibre insulation on. The wood is less than 1"x 5" (guess 22mm x 95mm) the space between the planks are about the equal size as the planks making the ceiling striped and similar to acoustic walls visually.. the plan is also to put a hanging roof below this roof with acoustical plates. (For fire safety)

On the short wall in opposite side of the stage there is 145mm insulation with a thick carpet on it, covering the lower half side of that wall.

In other words, it is an extremely dry room. I'm just in the beginning of this and will get photos and learn how to measure the room .

What would be your first recommendation?
Handling all kind of live music. (And also dance music)
Horns? Line arrays?

My setup now is a pair of omnitop15 and two titan48. I haven't found a good spot for titans yet, getting cancellations. I am happy with this , and do often get compliments for the sound. Since it's a small venue , I might build something smaller ..

The best if made possible without feedback would probably be to use FOH as monitors? Minimizing stage sound.

Sorry for the English, hope it's understandable and pictures will come if anyone finds it interesting enough to help with

Camillo wrote: ↑Mon Oct 28, 2024 1:01 pmSorry for the English...

No apology necessary. Understood just fine. Your English is way better than my Swedish.

...I haven't found a good spot for titans yet, getting cancellations...

If you don't mind sharing a little more information, I'd like to know what cab placements and deployment configurations you've tried and what specific results you experience with them.

Haha! Thank you Seth.

Well, not too many yet, had them laying down, wall loaded at each side first i think. It worked okay. Then standing up at each side. Once i raised the stage i put them centered together
in front of it , both straight and coupled. Had som blankets in front of them and noticed at a sound check that i couldnt get more bass and raising made the blankets move but no increase in sound.
I was sure the polarity was correct but switching made the trick, haha. Had to turn down the volume...
I panned el. Bass and kick drum to each cab and iirc that sounded a bit better , or easier to control.
Massive bass buildup in the height of the mixer(+2m), leaving that place walking around I find nulls and low response .

I want to use rew in order to find the best positions, but It would be great to have a good start of choices where to put them. Anything is considerable. . Along the side walls, ceiling , u name it or a good software perhaps, putting dimensions and door openings to see differences ..

But before that, I was thinking about speaker choice, since I'm planning on building some other bfm:s anyway.. (even though I might find it too hard to change the otop's). haha

So, this is a quick rough draft of the venue.
I might be able to record a 3d view soon though.

As said, venue is about 5x13x3 meters.
Stage is about 5x3 meters
In the left corner of the stage is a drum riser that is about 1.3 meters high from floor and 60cm from stage height.

One thought was to corner load the 2xt48 under the drum riser. A quick Google search lead to a forum where Bill wrote about the importance of distance from drum mics, causing feedback so I guess this isn't an option.

How crucial is the distance between the t48s and omnitops that are flown in line with the front of the stage? (Marked x) And is this generally a good location for the tops? Just time aligning?

I marked the walls a b c d. Corner loading in the other end of the venue? (Wall c)
Along the right (b) wall?

Since omnidirectioninal, does the mouth facing do any difference, facing from b to d (5 meters).

I guess i wouldnt need the t48s for this small venue but.. but..

Curious where to start.. haha
Thanks

In a room that size, I would personally gather as much data as possible and choose the best compromise. There will always be hot and cold spots, there's little chance of getting around it. It may be worth trying opposing corners, AB & CD. How much wall is there from the corner of AB and the 130cm opening on Stage Left (right side in drawing) on wall B?

Ah I see. Do you have any "dont's" for when I'm testing locations? Except from near mics that tend to feedback..

Seth wrote: ↑Sun Nov 17, 2024 2:25 pm How much wall is there from the corner of AB and the 130cm opening on Stage Left (right side in drawing) on wall B?

I'd say about 40cm.
With that doorway opened.. it's hard to calculate what happens to the subs, if placed in that corner, right?.except from a lot of sub going into the restaurant ..

A good way to save space and also hade storage would of course be built in under the stage somewhere..

No matter where the subs are the result in an adjacent room will be the same.

Bill Fitzmaurice wrote: ↑Mon Nov 18, 2024 5:55 pm No matter where the subs are the result in an adjacent room will be the same.

The best way to "protect" the other room is to highpass the subs around 50hz - that's plenty for live sound and will help to mitigate the low-end in the other room..,....it's not going away, but will be somewhat less annoying.

Bruce Weldy wrote: ↑Mon Nov 18, 2024 6:49 pm

Bill Fitzmaurice wrote: ↑Mon Nov 18, 2024 5:55 pm No matter where the subs are the result in an adjacent room will be the same.

I see. Even placed in a doorway/door opening?

The best way to "protect" the other room is to highpass the subs around 50hz - that's plenty for live sound and will help to mitigate the low-end in the other room..,....it's not going away, but will be somewhat less annoying.

Okay, well I'll have measure the room, a weak memory says it has a peak in the 40hz region som that might be good. I don't really have any issue with bass leaking to the next room, just had a thought that placing them in the AB corner in the sketch would increase the sub in the other room since it shares the same wall and it would be placed in the door opening then.

Where frequencies below 80 Hz are concerned there are no doors, there are no walls. That's why all you hear from the kiddies driving past in a $500 car with a $5000 sound system is boom-boom. Stopping bass frequencies requires a wall with extreme mass.

This is probably a boneheaded suggestion, but could a small width sub of the same design be placed in the restaurant, out of phase to the primary subs?

Rich4349 wrote: ↑Tue Nov 19, 2024 11:05 am This is probably a boneheaded suggestion, but could a small width sub of the same design be placed in the restaurant, out of phase to the primary subs?

Since the other room isn't the primary conversation point, I won't go down that rabbit hole. But briefly, yes there are situations where strategic placement and time/phase manipulation can be used to create intentional null zones. I'm nowhere near knowledgeable enough in the subject to speak to it with any sort of authority. That would be a learning conversation for me and would really demand it's own dedicated thread.

Camillo wrote: ↑Mon Nov 18, 2024 5:51 pm Ah I see. Do you have any "dont's" for when I'm testing locations?

Don't place the cabs in the no-go zone.

The no-go zone is a distance from a wall that is greater than a quarter wavelength of the highest frequency the cab's intended to create and less than a quarter wavelength of the lowest frequency.

To calculate those distances, divide the speed of sound in feet (or meters) per second by the frequency to get the wavelength. Multiply by 0.25 (or divide by 4) to get a quarter wavelength. The speed of sound varies with temperature, but I always use 1125fps in my calculations (343 meters per second)

So, for a bandwidth of 40Hz to 100Hz, the no-go zone is between 86cm and 214cm (2' 10" and 7') from a wall.

If you place the cab with the mouth in the no-go zone, the reflected soundwave will produce a deep cancellation centered on the frequency at which a quarter wavelength corresponds to the measured distance. "Centered" means that's the frequency the cancellation will be greatest. The cancellation will also effect frequencies surrounding the center cancellation frequency to a diminishing degree the further out a frequency is from the center frequency.

Best practice is to place the cab with the mouth aimed into a corner or angle loaded against a wall whenever possible.

You may also try putting the cabs together and angle loaded in the center of wall "D". I know it doesn't make sense to the eyes, but let your ears and measurement microphones determine the optimum position and placement. If I put a blindfold on you then guided you to stand where a huge stack of subwoofers were a meter away from you, immediately to your left, yet placed the mains in front of you and asked you to point to the subwoofers... if the subwoofers are playing cleanly without any distortion, even though you could literally raise your left arm and touch them, you won't be able to point to them. You'd most likely point in the direction of the mains, which is the only location your brain can possibly associate the frequency location... unless you already knew this, in which case you'd point elsewhere in hopes a random lucky guess could could look like you broke the laws of physics in relation to human physiology. LOL

Really truly though, try them on that wall in this configuration:


Here's a sticky thread if you haven't already seen it, Rules for Subwoofer placement and stacking.

Seth wrote: ↑Tue Nov 19, 2024 3:00 pm

If you place the cab with the mouth in the no-go zone, the reflected soundwave will produce a deep cancellation centered on the frequency at which a quarter wavelength corresponds to the measured distance.

Thank you Seth. Yes I've looked at the placement thread and considered different scenarios. Just a bit stuck in omnidirectional thinking since I probably don't understand it truly. So the mouth is still the important bit in the distance from wall, not the other sides of the cab?

Since two t48's probably is more than needed, (even if coupling smoothens the response,) I actually considered placing them under the drum riser, with one turned backwards inverted to cancel out the backwards sound but thats a bit over my head, haha.
Perhaps placing them in the AB corner as you suggested, even though it fully don't become a corner when the door is opened.. perhaps v-couple them on stage , using them as a riser for.. bassplayer. (Actually used my old Martin 115's for that on stage but not connected, just for.. beauty.. haha

Omnidirectional is just that, emanating equally in all directions from the radiating plane. The radiating plane of a horn is the horn mouth.

Camillo wrote: ↑Wed Nov 20, 2024 4:33 am

Seth wrote: ↑Tue Nov 19, 2024 3:00 pm

If you place the cab with the mouth in the no-go zone, the reflected soundwave will produce a deep cancellation centered on the frequency at which a quarter wavelength corresponds to the measured distance.

Thank you Seth. Yes I've looked at the placement thread and considered different scenarios. Just a bit stuck in omnidirectional thinking since I probably don't understand it truly. So the mouth is still the important bit in the distance from wall, not the other sides of the cab?

Since two t48's probably is more than needed, (even if coupling smoothens the response,) I actually considered placing them under the drum riser, with one turned backwards inverted to cancel out the backwards sound but thats a bit over my head, haha.
Perhaps placing them in the AB corner as you suggested, even though it fully don't become a corner when the door is opened.. perhaps v-couple them on stage , using them as a riser for.. bassplayer. (Actually used my old Martin 115's for that on stage but not connected, just for.. beauty.. haha

While I would try both configurations (among others), I want to clarify that my previous recommendation involving corner AB was to split the subs up, running one in AB and the other in CD in an effort to minimize null spots. To smooth out response throughout the room, not smoothing the cabs response... which occurs as you mentioned, with mutual coupling. Also, I forgot to mention... in testing this configuration and any other configuration where the subs are split up, run a test, then invert the phase on one of the cabs and see if anything changed for the better or worse in the room. I highly recommend keeping written notes on all the configurations and observations. Place masking tape on the floor with notes about that location. Test as many possible configurations and be as thorough in your documenting as you can.

As Bill pointed out, yes, the mouth is still the important part. In a direct radiating cab, the speaker cone is the "radiating plane". In a horn loaded enclosure, the horn mouth is the radiating plane. It's the distance from the radiating plane to a reflective boundary (or in some cases, the distance to another cabs radiating plane) that matters. Taking the T60 for example; if you were to place a T60 laying flat on the ground, against a wall, mouth aimed out away from the wall it would put the radiating plane of the T60 5 feet (1.5 meters) away from the wall, squarely in the No-Go zone... 56Hz null. In all reality, in a small room like you have, the reflections off nearly every wall will be strong enough to create areas where constructive summation makes certain frequencies in certain locations louder and destructive summation makes certain frequencies in some locations essentially disappear. It really truly is going to be a matter of choosing the configuration with the most favorable combination of compromises.

Personally, I would not be inclined to try the "one cab flip, drum riser orientation". However, testing it won't hurt anything and will add to your experience, knowledge, and understanding. So, I can't say it's the worst idea ever. If you're inclined, give it a go.

That said, I would absolutely test that location V-Plated and aimed into the corner. If it turned out to have the best response in the room and you wanted to put them under the drum riser, there are tricks you can use to eliminate feedback into the kick drum microphone, depending on the mixer you're using. What mixer are you using?