The No.1 Website for Pro Audio
subwoofer placement
Old 1 week ago
  #31
Gear Maniac
 

How large is the space?

as it was said earlier, your best bet is place your mains on top of the subs and call it a day. plus having your mains fire straight rather then at a toe'd in angle is better. buy some black duvetyne and gaff tape if you need to hide them or make them blend in better.

Do you plan on reinforcing the band? this space seems like the natural acoustics will carry most of the instruments and you will primarily be reinforcing the vocals, which you should be using a hpf on. not sure about the size of the space though. if this space was larger I think you'd at least have 4 tops or a set of delays so that's why I'm guessing its smaller and you won't be using that many mics.

toe'ing your mains in at an angle too much how you have them pictured in your first post can cause some feedback issues with mics on the stage if they have a wide throw angle. another reason to keep them on top of the subs preferably on the floor next to the two front corners of the stage. id add another set of tops if the space is larger then I'm thinking it is out wider, firing straight if the dance floor is wide.
Old 1 week ago
  #32
Gear Nut
 

If subs below tops is set for practical / esthetic reasons, I wonder if it would be a good idea to split the sub band in two (bass / sub bass) and send one band to either side. Clearly not as efficient as clustered/cardioid setups, but should take care of power alleys, shouldn't it?

Cheers, Peer
Old 1 week ago
  #33
Lives for gear
 

Quote:
Originally Posted by PeerSoe View Post
If subs below tops is set for practical / esthetic reasons, I wonder if it would be a good idea to split the sub band in two (bass / sub bass) and send one band to either side. Clearly not as efficient as clustered/cardioid setups, but should take care of power alleys, shouldn't it?

Cheers, Peer
theoretically, if there isn't too much overlap in terms of frequency range between the subs, the power alleys to some degree could get minimized - however, one would need to use ridiculously steep filters on the x-overs.

also worth noting that the room dimensions can have far bigger effects on the (combined) pattern behaviour of the subs than the spacing between them; in the op's situation, positioning the subs in the upstage corners would help to even out modal issues (but cause havoc on stage).

setting two of them on top of each other on one side of the stage touching the sude wall would get him the most output; setting them in front of the stage might get him the most even distribution while using a cardioid endfire array in the center position would keep the stage clear but lead to raised spl right in front of the array etc.

pic your poison...
Old 1 week ago
  #34
Quote:
Originally Posted by nephew312 View Post
How large is the space?

as it was said earlier, your best bet is place your mains on top of the subs and call it a day. plus having your mains fire straight rather then at a toe'd in angle is better. buy some black duvetyne and gaff tape if you need to hide them or make them blend in better.

Do you plan on reinforcing the band? this space seems like the natural acoustics will carry most of the instruments and you will primarily be reinforcing the vocals, which you should be using a hpf on. not sure about the size of the space though. if this space was larger I think you'd at least have 4 tops or a set of delays so that's why I'm guessing its smaller and you won't be using that many mics.

toe'ing your mains in at an angle too much how you have them pictured in your first post can cause some feedback issues with mics on the stage if they have a wide throw angle. another reason to keep them on top of the subs preferably on the floor next to the two front corners of the stage. id add another set of tops if the space is larger then I'm thinking it is out wider, firing straight if the dance floor is wide.
The barn is around 8 meter wide and probably 15-20 meters long, ceiling around 10-15 meters up, so it's a big rectangular shaped space, with a dance floor/stage on one side and bar / dining area on the opposite side.
We won't play super loud and if there are around 100 guests in total, not more than maybe 20-50 of them will be in front of stage .
Old 1 week ago
  #35
Quote:
Originally Posted by deedeeyeah View Post
theoretically, if there isn't too much overlap in terms of frequency range between the subs, the power alleys to some degree could get minimized - however, one would need to use ridiculously steep filters on the x-overs.

also worth noting that the room dimensions can have far bigger effects on the (combined) pattern behaviour of the subs than the spacing between them; in the op's situation, positioning the subs in the upstage corners would help to even out modal issues (but cause havoc on stage).

setting two of them on top of each other on one side of the stage touching the sude wall would get him the most output; setting them in front of the stage might get him the most even distribution while using a cardioid endfire array in the center position would keep the stage clear but lead to raised spl right in front of the array etc.

pic your poison...
Thank you deedeeyeah

I have two questions regarding cardioid endfire array's.
My subs doesn't have a DSP for cardioid mode built in.
1) Can I use an external dsp to get this working?
2) Just like power alleys/comb filtering, aren't cardioid endfire array's depending on specific frequencies? Like you can set it up to work perfectly for 50 Hz (1.7 m spacing, ¼ wavelength, 5 ms delay, ¼ cycle), but you will still have comb filtering at 80 or 40 for example?

Thank you
Old 1 week ago
  #36
Lives for gear
 

Quote:
Originally Posted by jallejulius View Post
Thank you deedeeyeah

I have two questions regarding cardioid endfire array's.
My subs doesn't have a DSP for cardioid mode built in.
1) Can I use an external dsp to get this working?
2) Just like power alleys/comb filtering, aren't cardioid endfire array's depending on specific frequencies? Like you can set it up to work perfectly for 50 Hz (1.7 m spacing, ¼ wavelength, 5 ms delay, ¼ cycle), but you will still have comb filtering at 80 or 40 for example?

Thank you
1) yes (i very much prefer to do so)
2) yes and no

for optimum coupling of subs, the spacing should be WITHIN a quarter of the wavelength of the frequency at which you're aiming so you got some range to play with.

it's true though than one can always ever optimally align a sub array (within itself and but also with mains, fronfills etc.) for one frequency and hence for one distance!

any frequency below or above that will measure less fine (will vary from predicted pattern, the lower the worse) and any distance shorter or longer than (a multitude of) the wavelength of the center frequency will combine worse with the rest of the pa.
if mains don't go very low, things become more easy; with a large overlap, things become tricky...

pic your poison part II



p.s. you need enough space behind (and above) the 2-box endfire array (well, anny subs...) for it to work properly: if haven't, you could as well just put them side by side (or advance one sub a bit; prediction becomes almost impossible but you can at least measure how much - if any - rear damping you get)...
Old 1 week ago
  #37
Lives for gear
Quote:
Originally Posted by deedeeyeah View Post
1) yes (i very much prefer to do so)
2) yes and no

for optimum coupling of subs, the spacing should be WITHIN a quarter of the wavelength of the frequency at which you're aiming so you got some range to play with.

it's true though than one can always ever optimally align a sub array (within itself and but also with mains, fronfills etc.) for one frequency and hence for one distance!

any frequency below or above that will measure less fine (will vary from predicted pattern, the lower the worse) and any distance shorter or longer than (a multitude of) the wavelength of the center frequency will combine worse with the rest of the pa.
if mains don't go very low, things become more easy; with a large overlap, things become tricky...

pic your poison part II



p.s. you need enough space behind (and above) the 2-box endfire array (well, anny subs...) for it to work properly: if haven't, you could as well just put them side by side (or advance one sub a bit; prediction becomes almost impossible but you can at least measure how much - if any - rear damping you get)...
Actually an end fire array where you have two or three rows of subs in front of the stage will remain perfectly time aligned (with it self, not with the mains) in the whole plane in front of it. If you use the same subs for both rows (you should), it will also remain in phase over the whole frequency range. The attenuation behind the array depends on the frequency.

If you want to achieve higher attenuation over broader range, you can add an additional row of subs or go for a cardioid array. Cardioid array provides somewhat constant attenuation across the whole frequency range, but you loose more power and it affects the frequency response in front of the array. In practice CSA usually works pretty well, especially if you use subs that were designed for this application.
Old 1 week ago
  #38
Lives for gear
 

Quote:
Originally Posted by jetam View Post
Actually an end fire array where you have two or three rows of subs in front of the stage will remain perfectly time aligned (with it self, not with the mains) in the whole plane in front of it. If you use the same subs for both rows (you should), it will also remain in phase over the whole frequency range. The attenuation behind the array depends on the frequency.

If you want to achieve higher attenuation over broader range, you can add an additional row of subs or go for a cardioid array. Cardioid array provides somewhat constant attenuation across the whole frequency range, but you loose more power and it affects the frequency response in front of the array. In practice CSA usually works pretty well, especially if you use subs that were designed for this application.
i wasn't referring to the phase* - sorry if i was implying this (due to my poor english).

i don't agree however with your claim that directional sub arrays show '(somewhat) constant attenuation across the whole frequency range':

in the real world, it's close to impossible to get the same amount of rear attenuation say at 30hz vs 90hz (and it'd be quite time consuming/difficult to measure); ime it's more like loosing ca. 3dB per octave.


* well, if an endfire array gets relatively long, you can actually start finding interesting effects towards the extremes: i got a chance to measure a 40m sub array which i set along the tarmac at an airshow and results were pretty far from prediction! if i ever find time, i might publish findings...


...which is unlikely though: not too long ago, i did a venue with a capacity of 12500 people with just a pair of dual 18" on each side: line arrays have become so efficient that imo days of huge sub array have mostly gone, at least indoors (of course assuming one gets to use mains capable of covering almost the entire frequency range).
Old 1 week ago
  #39
Lives for gear
Quote:
Originally Posted by deedeeyeah View Post
i wasn't referring to the phase - sorry if i was implying this (due to my poor emglish)

i don't agree however with your claim that directional sub arrays show '(somewhat) constant attenuation across the whole frequency range':

in the real world, it's close to impossible to get the same amount of rear attenuation say at 30hz vs 90hz (and it'd be quite time consuming/difficult to measure); ime it's more like loosing ca. 3dB per octave.
Alright then, might be my English too.

I wasn't referring to directional sub arrays in general but specifically to cardioid sub arrays which are different from the end-fire configuration. In cardioid array you delay the rear speaker and reverse it's polarity. The sound from the front speaker reaches the rear speaker at the same time that the rear speaker produces the same sound but with the opposite polarity. The waves produced by these speakers are constantly 180° out of phase behind the array, therefore cancelling each other out. Of course if you go into a reverberant room, things change a bit and if you move off axis, there won't be as much attenuation and it will become frequency dependant, but if you have a long CSA in front of the stage, the whole stage will be pretty much on axis.
Old 1 week ago
  #40
Lives for gear
 

Quote:
Originally Posted by jetam View Post
Alright then, might be my English too.

I wasn't referring to directional sub arrays in general but specifically to cardioid sub arrays which are different from the end-fire configuration. In cardioid array you delay the rear speaker and reverse it's polarity. The sound from the front speaker reaches the rear speaker at the same time that the rear speaker produces the same sound but with the opposite polarity. The waves produced by these speakers are constantly 180° out of phase behind the array, therefore cancelling each other out. Of course if you go into a reverberant room, things change a bit and if you move off axis, there won't be as much attenuation and it will become frequency dependant, but if you have a long CSA in front of the stage, the whole stage will be pretty much on axis.
hm...

guess we'd need to more clearly separate between desired effects of cardioid and hypercardioid arrays, how far behind the array we're measuring and then differentiate between physical setup of endfire vs csa vs stairstep but also between 3 or 4-box csa's, where we put the rear-firing sub etc.


...all of which i guess is WAY beyond the scope of this thread?

___


to the op: could you maybe provide a pic or two and some details about the stage construction? and tell us what you are trying to achieve by using a specific sub array setup?
Old 1 week ago
  #41
Here for the gear
 

At a gig like that I'd suggest that the pa is slightly underpowered. It's a decent pa (my hard rock band uses similar Alto gear) but I think you need every ounce of volume you can get out of it.

When you say barn I assume the walls are solid? If that's the case I'd place the subs both on one side, against the wall and use them as a stand for one of the tops. That way they're clustered so you get a volume boost but, unlike the centre-cluster option, there's some wall loading boost too.

Pick the side opposite the bass player and have them use slightly more stage volume than they normally would to balance it out a little. LF is not very directional, so you wont need much extra stage volume (too much will actually cause fresh cancellation issues between amps and subs as if you had separated subs) but a little extra will help.
Old 6 days ago
  #42
Lives for gear
 
Don S's Avatar
 

Great article, I hope it helps
https://www.soundonsound.com/techniques/bass-place
Old 5 days ago
  #43
Quote:
Originally Posted by Don S View Post
Thank you very much, I have already read that article, its a very good and informative one.
Old 5 days ago
  #44
Quote:
Originally Posted by User4114 View Post
At a gig like that I'd suggest that the pa is slightly underpowered. It's a decent pa (my hard rock band uses similar Alto gear) but I think you need every ounce of volume you can get out of it.

When you say barn I assume the walls are solid? If that's the case I'd place the subs both on one side, against the wall and use them as a stand for one of the tops. That way they're clustered so you get a volume boost but, unlike the centre-cluster option, there's some wall loading boost too.

Pick the side opposite the bass player and have them use slightly more stage volume than they normally would to balance it out a little. LF is not very directional, so you wont need much extra stage volume (too much will actually cause fresh cancellation issues between amps and subs as if you had separated subs) but a little extra will help.
Thank you !

Regarding the PA. Will it be the subs that peaks first?
We wont play super loud, just loud enough for the people on the dance floor, which will be pretty much just in front of the speakers, so I don't think we need to play any louder than we usually do. Or would you hire an additional sub for such an event?
Old 5 days ago
  #45
Here for the gear
 

Quote:
Originally Posted by jallejulius View Post
Thank you !

Regarding the PA. Will it be the subs that peaks first?
We wont play super loud, just loud enough for the people on the dance floor, which will be pretty much just in front of the speakers, so I don't think we need to play any louder than we usually do. Or would you hire an additional sub for such an event?
Outside it definitely will yes, you lose all of the room boundary reinforcement that really helps. It really depends on what you mean by 'barn'.

We use our TS115A and TS18A per side on inside gigs all the time and it works a treat. For the biker rallies and mini festivals we play over the summer we rent a much more capable PA. Specifics vary depending on what exactly the company brings but it's more often than not a JBL system that is 2x 2x15" and 2x 2x18" PER SIDE. In other words for the same number of people (or not many more) we have about 8x the number of drivers and probably a similar boost in power.

We once turned up for what we thought was a pub gig only to find out that it was actually a bike rally in the back field. We'd been booked on word of mouth from an event the previous summer, but the person who made the booking made it from the pub's facebook account and the gig was on a Saturday evening so we ASSumed and only brought the Alto PA. The sound was....disappointing even at soundcheck when most of the people were outside enjoying the sun. By the time that dancefloor filled we were quite meek, especially for biker's tastes. We spent the whole gig wishing that we'd known so we could have cross rented. The poor DJ let us run the vocals through his PA as well as our own, we only really miced the drums and relied on amp stage volume as much as possible. This was a marquee not a barn but sometimes there isn't much distinction depending on how the barn is made!




By comparison, here's another biker rally the same summer with a (terrible!) shot of the PA that we recommended the organiser rented for us and our support act. This was taken during their last song as we were waiting to go on.
Old 5 days ago
  #46
Quote:
Originally Posted by User4114 View Post
Outside it definitely will yes, you lose all of the room boundary reinforcement that really helps. It really depends on what you mean by 'barn'.

We use our TS115A and TS18A per side on inside gigs all the time and it works a treat. For the biker rallies and mini festivals we play over the summer we rent a much more capable PA. Specifics vary depending on what exactly the company brings but it's more often than not a JBL system that is 2x 2x15" and 2x 2x18" PER SIDE. In other words for the same number of people (or not many more) we have about 8x the number of drivers and probably a similar boost in power.

We once turned up for what we thought was a pub gig only to find out that it was actually a bike rally in the back field. We'd been booked on word of mouth from an event the previous summer, but the person who made the booking made it from the pub's facebook account and the gig was on a Saturday evening so we ASSumed and only brought the Alto PA. The sound was....disappointing even at soundcheck when most of the people were outside enjoying the sun. By the time that dancefloor filled we were quite meek, especially for biker's tastes. We spent the whole gig wishing that we'd known so we could have cross rented. The poor DJ let us run the vocals through his PA as well as our own, we only really miced the drums and relied on amp stage volume as much as possible. This was a marquee not a barn but sometimes there isn't much distinction depending on how the barn is made!


By comparison, here's another biker rally the same summer with a (terrible!) shot of the PA that we recommended the organiser rented for us and our support act. This was taken during their last song as we were waiting to go on.

Thank you, very interesting!

If these two gigs (on the photos) were indoor, with solid walls, would your current PA have been enough?

Luckily we have the TS3-version so the SPL rating has increased from 126dB peak, 123dB continuous to 134/131 for both the tops and the subs. But still, I don't want to push them to hard since I've read to many stories about people who have blown the drivers.

If you were about to upgrade, would you start with the tops of subs first?
Old 5 days ago
  #47
Lives for gear
 

Quote:
Originally Posted by User4114 View Post
Outside it definitely will yes, you lose all of the room boundary reinforcement that really helps. It really depends on what you mean by 'barn'.

We use our TS115A and TS18A per side on inside gigs all the time and it works a treat. For the biker rallies and mini festivals we play over the summer we rent a much more capable PA. Specifics vary depending on what exactly the company brings but it's more often than not a JBL system that is 2x 2x15" and 2x 2x18" PER SIDE. In other words for the same number of people (or not many more) we have about 8x the number of drivers and probably a similar boost in power.

We once turned up for what we thought was a pub gig only to find out that it was actually a bike rally in the back field. We'd been booked on word of mouth from an event the previous summer, but the person who made the booking made it from the pub's facebook account and the gig was on a Saturday evening so we ASSumed and only brought the Alto PA. The sound was....disappointing even at soundcheck when most of the people were outside enjoying the sun. By the time that dancefloor filled we were quite meek, especially for biker's tastes. We spent the whole gig wishing that we'd known so we could have cross rented. The poor DJ let us run the vocals through his PA as well as our own, we only really miced the drums and relied on amp stage volume as much as possible. This was a marquee not a barn but sometimes there isn't much distinction depending on how the barn is made!

By comparison, here's another biker rally the same summer with a (terrible!) shot of the PA that we recommended the organiser rented for us and our support act. This was taken during their last song as we were waiting to go on.
yep: outdoors is a vastly different scenario...

setups also depend on expectation, venue, genre, budget, setup time, etup, orientation, alignment etc. - and the era: while it used to be okay to go with a (very crude) ratio of 1 watt per person back in the late 70s, it's at least 10 times as much these days (and this with amps, drivers and arrays being vastly more efficient)!

if you're into reggae, large parts of the audience will be disappointed if you cannot provide a serious low end ooompf while the very same setup and alignment is not the typical way how to deploy gear for americana etc.

even the mix technique can affect what you need: some techs rely on an overwhelming strategy, others prefer a more differentiated and dynamic approach.
Old 5 days ago
  #48
Here for the gear
 

Quote:
Originally Posted by jallejulius View Post
Thank you, very interesting!

If these two gigs (on the photos) were indoor, with solid walls, would your current PA have been enough?
The first one would be possible but definitely on the very limits, the second one is actually substantially bigger and we wouldn't stand a chance.

Quote:
Originally Posted by jallejulius View Post
Luckily we have the TS3-version so the SPL rating has increased from 126dB peak, 123dB continuous to 134/131 for both the tops and the subs. But still, I don't want to push them to hard since I've read to many stories about people who have blown the drivers.
I really, really like our Alto system and it works well. I certainly have no doubt that the newer models are an upgrade but I would still expect those numbers to have been decided on by the marketing team and not the engineering team. As ever, use your ears. Unfortunately that advice is very hard to follow when wearing earplugs, standing behind the system, being screamed at by a crowd.

Quote:
Originally Posted by jallejulius View Post
If you were about to upgrade, would you start with the tops of subs first?
Probably the subs but the truth is that the upgrade path is simply a new system when we need it. This links quite neatly into this:

Quote:
Originally Posted by deedeeyeah View Post
yep: outdoors is a vastly different scenario...

setups also depend on expectation, venue, genre, budget, setup time, etup, orientation, alignment etc. - and the era: while it used to be okay to go with a (very crude) ratio of 1 watt per person back in the late 70s, it's at least 10 times as much these days (and this with amps, drivers and arrays being vastly more efficient)!

if you're into reggae, large parts of the audience will be disappointed if you cannot provide a serious low end ooompf while the very same setup and alignment is not the typical way how to deploy gear for americana etc.

even the mix technique can affect what you need: some techs rely on an overwhelming strategy, others prefer a more differentiated and dynamic approach.
Totally. I'm talking about my hard rock band: we open with 'Born To Be Wild' then it goes from Queen and Blink 182 at the gentler end through to Motorhead and Rage Against The Machine at the other. We need to be loud and the truth is that the Alto is budget gear. Budget gear that punches well above its weight but still.

For comparison my other band is much gentler (mostly indie rock) and we have 2 RCF 732 over a single 7005II and it blows the Altos away in terms of output. Between the fact that the pa is much more capable and that the crowds we get in the lighter band want it quieter anyway we have never had to cross rent with that system. I'd push the heavy rock band into something more like that if we ever needed to upgrade the Altos. I imagine a pair of RCF 735 over a pair of 7008ii would be substantially more capable than our Alto system despite being the same driver configuration, size and weight.
Old 5 days ago
  #49
Quote:
Originally Posted by User4114 View Post
The first one would be possible but definitely on the very limits, the second one is actually substantially bigger and we wouldn't stand a chance.

I really, really like our Alto system and it works well. I certainly have no doubt that the newer models are an upgrade but I would still expect those numbers to have been decided on by the marketing team and not the engineering team. As ever, use your ears. Unfortunately that advice is very hard to follow when wearing earplugs, standing behind the system, being screamed at by a crowd.

Probably the subs but the truth is that the upgrade path is simply a new system when we need it. This links quite neatly into this:

Totally. I'm talking about my hard rock band: we open with 'Born To Be Wild' then it goes from Queen and Blink 182 at the gentler end through to Motorhead and Rage Against The Machine at the other. We need to be loud and the truth is that the Alto is budget gear. Budget gear that punches well above its weight but still.

For comparison my other band is much gentler (mostly indie rock) and we have 2 RCF 732 over a single 7005II and it blows the Altos away in terms of output. Between the fact that the pa is much more capable and that the crowds we get in the lighter band want it quieter anyway we have never had to cross rent with that system. I'd push the heavy rock band into something more like that if we ever needed to upgrade the Altos. I imagine a pair of RCF 735 over a pair of 7008ii would be substantially more capable than our Alto system despite being the same driver configuration, size and weight.
Interesting to hear that you can even use your Alto's for live shows anyway, since it's their first generation speakers at a sub 1k price!

Sound reinforcement isn't really that expensive to begin with, but it scales really really damn fast as you want to climb the SPL ladder!

You can get an OK set for small events, bars etc for around 1k, but you have to double that if you just need a little bit more, and then you have to double that figure again for the next level .
And if you want to do big shows, 10k-20k wont even put you on the map
📝 Reply
Topic:
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
🖨️ Show Printable Version
✉️ Email this Page
🔍 Search thread
♾️ Similar Threads
🎙️ View mentioned gear
Forum Jump
Forum Jump