So I’ve bee asked to help a friend who has a pretty successful rock tribute band assemble a Portable system for use in small to medium size venues including some outdoor fair type events. I’d like to keep it simple as possible with mibass/high freq signals in one pair of boxes and a pair of subs.
I really am impressed with the hybrid array systems out there using a line source of full range drivers combined with a single point source midbass. Choosing a suitable fullrange driver brings up a lot of questions.
First off, off axis response......seems to be that considering what’s currently available 2.5”drivers are about as large as possible and still retain suitable off axis response for PA use in the above scenario where wide horizontal coverage is ideal. My search has landed on the SBAcoustics SB65 SB Acoustics SB65WBAC25-4 2.5" full range as the best choice considering array design parameters. My thoughts are 8 drivers per side.
My second choice which doesn’t follow the above guidelines would be to use a line of ring radiator dome tweeters, particularly the SBAcoustics SB29RDC SB Acoustics SB29RDCN-C000-4 Neo Magnet, Ring Dome Tweeter. These have a very low FS, much better off axis response and higher power handling and efficiency. My thoughts say that eight of these would cross third order at 1.5khz without issue.....or am I delusional in the context of PA use? I’d use these with a vertical pair of 10”midbass in a hybrid linesource box.
Thoughts?
I really am impressed with the hybrid array systems out there using a line source of full range drivers combined with a single point source midbass. Choosing a suitable fullrange driver brings up a lot of questions.
First off, off axis response......seems to be that considering what’s currently available 2.5”drivers are about as large as possible and still retain suitable off axis response for PA use in the above scenario where wide horizontal coverage is ideal. My search has landed on the SBAcoustics SB65 SB Acoustics SB65WBAC25-4 2.5" full range as the best choice considering array design parameters. My thoughts are 8 drivers per side.
My second choice which doesn’t follow the above guidelines would be to use a line of ring radiator dome tweeters, particularly the SBAcoustics SB29RDC SB Acoustics SB29RDCN-C000-4 Neo Magnet, Ring Dome Tweeter. These have a very low FS, much better off axis response and higher power handling and efficiency. My thoughts say that eight of these would cross third order at 1.5khz without issue.....or am I delusional in the context of PA use? I’d use these with a vertical pair of 10”midbass in a hybrid linesource box.
Thoughts?
Which ones are you impressed with? I have only heard a couple and they both sounded nasty when pushed to even moderate levels, and I guess this rock band has a drummer, so even without micing up the drum kit, you will need a reasonable SPL - certainly more than the ones I have heard to could do nicely
Brian
Brian
Anyway you will need 4-band system.
LF - powerful outdoor subwoofer based on something 18” like Eighteen Sound 18LW1400 or RCF LF18X401. Say ROAR18.
MB - something midbassy, much more fast than LF-sub, based on something like Eighteen sound 15MB650.
Mids - say 12x line array of something from relatively cheap Visaton FRS8M and up to comparatively expensive FaitalPRO 3FE22.
Highs - first thought is to use highly-cutted huge ribbon like Swans RT2H-A, placed as high as possible, next is to filter some highs from higher and lower mids in array, this will greatly rise vertical HF directivity for the price of sensitivity. Also you can try to pick better directivity by removing coherence at HF like PeeckerSound do:
12x vertical 3” array really have sound fullfulling stereo effect and very clear voice reproduction in 500-3 kHz band. There are a lack of vertical directivity, say sitting ~5-10 meters apart you doesn’t hear highs. Also, due to cylindrical wave there are very different loundness falling with distance. But there you will need something very fast in the midbass region 80-200 Hz, because even cheap Visatons provide incredible MMs/Bl ratio in midrange and midbass driver must follow them.
Also, you can try to make bandpass array box, for example FRS8:
Also thoroughly read this Keele paper:
https://www.audioartistry.com/Papers/CBT Paper6 PerformanceRankingof Line Arrays.pdf
https://www.audioartistry.com/Papers/CBT Paper6 PerformanceRankingof Line Arrays.pdf
4-way systems are over-complicated, and don't make sense unless you're going for large-scale sound reinforcement - see Nexo Alpha for an example.
The difficulty in getting everything up and running nicely increases exponentially with the number of crossover points.
Here's what you can do with a 3-way system: YouTube
Which was:
1x 18Sound ND1460
2x Faital Pro 10FH520
2x Faital Pro 15HP1060
Per side.
If you're doing venues (or SPLs) significantly larger than that, I'd consider a 4-way system. Anything smaller, and 3-way will do the job.
Chris
Not so much, modern digital filtering and comparatively cheap TD amps make huge things with easy.
Say a pair of DBX Driveracks, one per side, and triple of china FP10000q make a pretty venue anyway and everywhere.
Say, quad of LF18X401, pair of 15MB650, pair of 6ND410 and pair of 3” HF driver with appropriate 2” horn.
Any electromechanical system performs really good not more than two octaves.
40-120 Hz 18” subwoofer
120-400 Hz 12-15” midbass
400-2k Hz 6-8” mids
2-10 kHz horn highs.
Pushing sub higher will remove LF fundamental, excluding midbass will limit punchability, removing mids or pushing HF driver lower will raise THD and limit available power.
No other way.
Here’s what can be actually done in a two-way:
Fane Sovereign 12-250TC in a front horn (~105 dB sensitivity, ~500 wt and a total Q as high as ~1,2) + LF18X401 in a half-of-m^3 ROAR18.
Using DBX Driverack PA2 or 260 they could be tuned to a +-0,3 dB line from 40 Hz up to 12-15 kHz. Sounds very good, but have no chance vs previous 4-way setup.
Directivity, mid clarity, punchability at lower midbass, upper highs reproduction, usable distance with area fullfillness are very different.
Not sure why the DIY tendencies here are still with big boxes and 4 way systems. Most commercial systems are moving towards smaller arrays for small/med duty systems hence my start of a discussion on the capabilities of small format fullrange drivers. Large format systems create so many lobes that the audience always has that disjointed PA feel where an array of drivers carrying all of the most important info sound more cohesive and natural with no beaming.
Mostly because of desired level and space to fullfill.
I have 12x2,5” per column sticks.
They totally lack of low punch with breastbone kick, higher HF octave and also they have very narrow vertical HF dispersion without special attention.
Commercial systems moving that way due to very realistic midfreq sound reproduction and low tendency to floor/ceiling reflections.
Very attractive stereo fulfilling also is real argue for arrays while moderate levels are demanded.
Yes, that effect are real while you are limited in placing height and aggravates by huge scene width.
Always think about speaker as a flashlight, wide beam angle - short distance, narrow beam angle - long distance.
While you have a fixed beam angle at your speakers and needs even sounding through hall/area- you really need to optimise listening distance and placing height.
Array is a compromise in this terms like wide beam and MODERATE distance and they are attractive due to this at MEDIUM listening levels.
It's simple really, the system you propose just isn't capable of generating the SPL required to support a rock band. If that stack of tiny fullrange drivers can generate 120dB@1m it'll be at full rated power which won't sound any good and doesn't leave any headroom, a traditional PA system can do that with 100w or less and at vastly lower distortion levels.
If you still want to do a line source for live band use you need to scale it up to use 5-6" fullrange drivers and a row of tweeters, the system needs too have a nominal sensitivity of somewhere close to 100dB so that moderate rock band SPLs can be obtained at relatively low input power levels leaving lots of room for dynamics.
Last edited:
Outdoors with depth/width ratio more than 3 or lower 1/3 and near/inbetween high buildings could be a really nightmare.
I mentioned midbass support in a hybrid configuration in the original post so yes, if high passed at 500hz, I’m confident the 8 2.5”drivers will be just fine. Sensitivity of the array should be in in the 96db 1w1m range but amp watts are cheap these days so less of a concern. And let’s be realistic.....NOTHING BELOW 1khz with baffle step has a sensitivity over 100db for a single drive unit.
Your scenario of 5-6” midbass drivers was also discussed in my first post as I was thinking of 8 6”midbass crossed to a line of the above mentioned tweeters at 1.5khz. These tweeters have much better off axis response than the fore mentioned 2.5”fullrangers and have a sensitivity of 94db per unit across their passband.......they also handle 80w program per unit as well and have an Fs of 670hz with minimal HD products measured at these power ratings and crossover point.......but each tweeter is twice the price of the 2.5 fullrange and for 16 drivers that’s another $500 for a pair of mid/high cabs. I “ could “ use the 2.5” fullrangers like a tweeter and cross at 1khz as well but I’m fearful of the poor off axis response above 8khz.......I think the array would need to be horizontally angled driver to driver to get good coverage to 30 degrees.
Although not discussed, the plan is 4 18” Neo subs in compact ported boxes for easy portability.
This has a much better chance of delivering acceptable results IMO, all those Bose L1 type systems are pretty awful sounding when pushed up to rock band sound levels.. despite the BS reviews all over the web.
You got to pay to play in this league, the 2" exit compression drivers in my "band PA" system cost close to $400ea, that is the only other solution that produces the kind of results required here.
Keep in mind array have a very different SPL vs distance falling than a single driver.
Very bad crossover freq.
Peak of the human ear sensitivity and a tons of beamforming/lobe effects.
2,5” array are better because it could be crossed from ~300 to 5000-8000 Hz and cover most demanding freq range in a single band.
No, double array of 5”-6” with 2,5” crossed at ~one kHz is a really bad idea.
Horisontal off-axis response at HF are really wide, allows for very wide stereo-effect listening PA space.
But vertical off-axis could be very tricky.
It’s very narrow at HF:
Your array must be carefully placed at a level of the listener’s ears or they will not hear anything higher ~some kHz.
View attachment 739201
Also there are a very bad effect while first rows pick all of the array sound benefits while second ones receives all of the difraction at the heads of first ones.
Yes, it’s the one of the most easy ways to destroy coherent array beamforming at HF.
But you better to scale up famous Dr. Keele CBT36 (CBT24) to 27x per column 3” cheap drivers like Visaton FRS8M and really have ultrahigh PA performer.
It will be ~2-2,1 meters height and provide uniform sound field up to ~15-20 meter distance.
Also you can use relatively cheap Behringer DCX2496 and 5x ~100 wt + 1x 300 wt amps per column for appropriate segment delay settings and rearrange drivers to straight column.
Yes, you can’t provide natural metal goosebumps feelind from Zildjian’s without some HF support, but midband and voice reproduction will be at order higher level from classic PA 3-ways.
Thanks for the detailed reply. Some more info......
Although I appreciate your concerns for vertical directivity, this systems primary function is for level ground plane use with all listeners on the same level and typically for venues with an average ceiling height of 10-16 ft. and no larger than 20x40 meters.
Since my last posting, I did some research and sims of a 2” fullrange from Eminence, the Alpha 2 which looks like an ideal choice of price vs performance in a vertical array of 16 units per side with each side supported by a pair of vertical 12” midbass drivers. Each Alpha 2 has a rising response which should naturally combat HF losses in a vertical alignment due to comb filtering.
Eminence Alpha 2-8 2" Full-Range Speaker 4 Pack
Each mid/high box would roughly be 40” tall and 18” wide and ideally pole mounted and adjusted for stage/ceiling height accordingly allowing for flexibility.
My thinking is to run the 12”drivers up to 400hz and have the 2” fullrangers take over from there.
Now some food for thought.......given the typical ceiling height and level plane use, i’m considering extending the HF response for more air and detail by using a single super tweeter per side on the top of each column for 8khz and up with a conical 40 degree pattern. I’m thinking to rely on the usually hard and reflective ceiling surfaces to return that high frequency energy back into the space. Would something like this be beneficial or destructive? The super tweeter would be on average 1.5-2meters above the listening vertical axis.
Last edited:
It must be noted that this comes with a lot of caveats.
Also, if you did have part of the frequency range as a line array, your tonality would vary as you move closer or further away from the speakers.
At far distances, you'll have a lot more from the array than the point source components, so now you have an uneven frequency response.
If you use a curved array or taper in some way, you lose the extended "throw" of a line array (since it's now a point source again), and you might as well have just used a good 12" driver.
For a PA system with 4x 18" subs, a pair of 12" 2-way tops is the way to do it. There's a reason why people keep coming back to that format - it works. The results are predictable and consistent.
Chris
No. Just because of clearly similar effects between 12” and 2” throat horn at a most demanding freq’s 800-2000 Hz.
More often no.
4x18” subs demands at least for 15” 3-way tops like RCF HD1531.
XO’ing 12” with 2” horn are not a good idea at all.
The PTMini-6 Planar Tweeter 6 Ohm Specification Sheet is a perfect match for 2 or 4 Visaton FRS 8M's and is a line source on it's own for the higher frequencies. I have made both, listening now to the 4 driver version with 5k x-over as tops in 2.1 with 2 sealed 8" for bass.
2x27 Pieces is very loud but not very transportable. I would go for 4x8/9 (4/8 Ohm, 2 each side, also better to adjust to width of the location/setup) which is >100dB/w and 500+W or about 2x125dB output.
Last edited:
If you want to support a rock band you really want the kick (60-70Hz) and snare (upper mid 150-200Hz) to punch trough. like really slam in the chest.
In my opinion many so called compact line arrays fail at that point.
They sound clean and "hifi" you could say. And for a DJ playing compressed recorded music it's ok.
Use a live rock band and it doesn't work. Almost always the low mid and mid is compromised.
There will be sizzling highs. Lots of sub and thats it (like putting a V curve on a graphic EQ)
Vocals sound cold and most of the time you don't hear what they are singing.
Snare drums have no impact same as for toms.
And the kick sounds like the building is falling down but there is no attack. (or they try to add attack using 4k boost and it starts clicking.....)
Ok sorry for my large complaining....(I have been at to many events with bad sound because of this....)
For small venues, what is wrong with using a simple top with a sub underneath?
a 15" with a 5 or 6" mid and a 1" CD can sound really good. or else
use 2 12" woofers with a 5 or 6" mid and a 1" CD
if you want extra punch use 2 15" drivers but then it will not be that portable anymore. (I have build a system using 2 15" drivers in the tops and everybody loves the sound, the 15"s where 101db efficient so using 2 it gets loud easely and it does 60Hz, not many PA tops go that low but they should)
For subs I think 2 double 18"s can work very good. (If possible cross them at 60Hz or something) the subs will do sub the rest should come from the top speakers.
The punch coming from 12 or 15" woofers is something you can't really get out of an array of small speakers.
Look for some info about line array theory and look how long the line must be to really function as a line array. Even for the vocal range you would need a long array
Keep it simple I would say 😉
To keep it portable horn loading is out of the question I think.
Altough I once used the Xtro tops and they could really work. Only the midhorn could use something better maybe.
For small venues Ground stack with simple top speakers works really good.
If you use horn loaded tops you will have more headroom and also really nice for rock but less portable.
Now for BIG venues go with (large) arrays and you would need infills because large arrays go far but have small dispersion. but BIG venues are a whole other story and this was not the question.
My opinion for something that works and is reliable => decent front loaded tops with good drivers on top of double 18"s.
Use decent drivers (beyma,rcf,18sound,etc) and use decent amplifiers.
It's just my opinion 😉
In my opinion many so called compact line arrays fail at that point.
They sound clean and "hifi" you could say. And for a DJ playing compressed recorded music it's ok.
Use a live rock band and it doesn't work. Almost always the low mid and mid is compromised.
There will be sizzling highs. Lots of sub and thats it (like putting a V curve on a graphic EQ)
Vocals sound cold and most of the time you don't hear what they are singing.
Snare drums have no impact same as for toms.
And the kick sounds like the building is falling down but there is no attack. (or they try to add attack using 4k boost and it starts clicking.....)
Ok sorry for my large complaining....(I have been at to many events with bad sound because of this....)
For small venues, what is wrong with using a simple top with a sub underneath?
a 15" with a 5 or 6" mid and a 1" CD can sound really good. or else
use 2 12" woofers with a 5 or 6" mid and a 1" CD
if you want extra punch use 2 15" drivers but then it will not be that portable anymore. (I have build a system using 2 15" drivers in the tops and everybody loves the sound, the 15"s where 101db efficient so using 2 it gets loud easely and it does 60Hz, not many PA tops go that low but they should)
For subs I think 2 double 18"s can work very good. (If possible cross them at 60Hz or something) the subs will do sub the rest should come from the top speakers.
The punch coming from 12 or 15" woofers is something you can't really get out of an array of small speakers.
Look for some info about line array theory and look how long the line must be to really function as a line array. Even for the vocal range you would need a long array
Keep it simple I would say 😉
To keep it portable horn loading is out of the question I think.
Altough I once used the Xtro tops and they could really work. Only the midhorn could use something better maybe.
For small venues Ground stack with simple top speakers works really good.
If you use horn loaded tops you will have more headroom and also really nice for rock but less portable.
Now for BIG venues go with (large) arrays and you would need infills because large arrays go far but have small dispersion. but BIG venues are a whole other story and this was not the question.
My opinion for something that works and is reliable => decent front loaded tops with good drivers on top of double 18"s.
Use decent drivers (beyma,rcf,18sound,etc) and use decent amplifiers.
It's just my opinion 😉
- Status
- Not open for further replies.