Active Speakers

[rob.d]

Isn't a peak output based on the drivers peak power handling figures and worked theoretically, the continuous output usually being around 6db less than this?

 

Its a genuine question.... is that the same principle for powered boxes or do they use the maximum amplifier power or limiter threshold to determine the peak spl? is this still done in a theoretical sense or is it measured.

 

In any real world scenario that particular stat is probably no more than a guideline, which applies more generally IMHO to any SPL peak calculation for a speaker box (not saying this is the case here, but some manufacturers do overblow the stats a little anyway). I'm only speculating- but I'd guess in this case its still in the realm of mathematical calculation. Then again, vs an equivalent unpowered system you'll probably find it easier to achieve the loudest possible sound. Anyway, bottom line is I dont know.

 

My line of thought in speculation being, that as a general rule, the presence of DSP beyond an active crossover in the more advanced active kit- theres no reason, for example, that you couldn't pop an individual level limiter in between the crossover and amp set at exactly the right point to yield maximum output from the driver. Beyond that, many manufacturers now fit time and phase alignment cleverness to their kit, and in some cases it works spectacularly well, which I would guess can only be beneficial to peak SPL output because it reduces comb filtering, certainly until you plug in the other box of the pair. I've seen a few that also incorporate some fairly advanced adaptive speaker management as well, beyond the reach of an unpowered system. For example, KV2 EX (I think, I've read it in somebody's catalogue anyway...) boxes can decide to roll off a bit of sub if it thinks the woofer has had a pounding in the last few minutes- it actually knows when your causing it to power compress! I doubt you can achieve that with a Driverack regardless of how long you spend tuning it. Which I suppose leads us back to the OP. Score + 1 active!

 

In defence of passive/ unpowered systems- if you've got a truck full of Mackies, and they go into thermal or otherwise power supply shutdown, you cant reset them remotely. Fair enough if they're at head height, but very not fun if theyre 20 feet above you head and the audience are beying for blood... This actually happened to a friend of a friend.

[Rob_Beech]

Thanks for that. I understand what you are saying with the advanced management. I suppose its one step up from returns and "sense" lines in such as the D&B subs. I think thats been mentioned either in this thread or somewhere else.

 

I think generally speaking this thread answers the powered/unpowered active/passive however you want to put it question fairly well. As has been said times many, there are advantages and disadvantages to both. I dont think its fair to say one is better than the other, but there are situations where a powered box or boxes are ideal and you'd be silly to suggest something else, there are occasions (Mark Payne gives a great example here) where a powered box is probably out of the question.

 

I think one thing we can all be certain of, theres some damn good powered systems out there of which examples lay in this thread, theres also some terrible ones. And the same applies to unpowered ones. I tend to work the cost out like for like. If I am spending £1000 per box and say £500 per amp channel then a powered box that costs £350 isn't going to perform the same way. Likewise, a pair of 12 + horn speakers at £95 a pair isn't going to outperform some of the smaller powered boxes on the market like the SRM450.

 

 

Rob

[dan slv-tech]

Hi,

 

I used to be an active guy (wernt we all ) I used to have a HK actor rig, for what it was it was ok, but the limiting was so harsh even at sensible levels, I since found out the limiter came in way before it needed too, would have cost more to have put a gradual limiter in....

 

Sold it, moved on to Unpowered boxes- wow what a difference, ok totally different rig, but now I set the points for crossing over, limiting etc, I can EQ each component in the rig...true alot more messing around, but so much more flexability, and as been said before, I can use the boxes outside and not have to worry bout water v power- And I load my rig in such a way I have redundant power left in the amp racks so if an amp dies, a quick bit of repatching and im away again, dont think active has that luxury quite yet.

Convection cooling isnt all that great, just moves heat from the hot components to a heatsink that then tries to get rid of the heat- Fans in an amp pushing/pulling air much moe effective (depending on your choice of amp tho!)

 

The low end active gear ie not meyer,adamson etc its not much cop, yes nice and lightweight, if its a better brand you get two amps inside the box powering the components.... tho has anyone ever thought that a 100watt amplifier on a 400watt 15inch box is a little steep? now either the horn isnt up to much to start with so t has to have heaps of power to drive it or the amp isnt doing what it says??

I have a 6Kw system and the 1inch only has 100w amp driving it!

 

Anyhow, plastic boxes are not great- outside in the van they get cold, brittle, drop them and say goodbye to the corners or worse, drop a wooden box, worse case- filler and a repaint!

 

Just my thoughts..........

[Mark Payne]

I've seen a few that also incorporate some fairly advanced adaptive speaker management as well, beyond the reach of an unpowered system. For example, KV2 EX (I think, I've read it in somebody's catalogue anyway...) boxes can decide to roll off a bit of sub if it thinks the woofer has had a pounding in the last few minutes- it actually knows when your causing it to power compress! I doubt you can achieve that with a Driverack regardless of how long you spend tuning it. Which I suppose leads us back to the OP. Score + 1 active!

 

Hi Rob.

Well we dont need active speakers for this kind of control. In the case of d&b the Epac/P1200/D12 amplifiers all electronically(P1200)/digitally(Epac/D12) model cone excursion (CE) and voice coil temperature (VCT) as well as general level limiting. Think of this as a kind of engine management system. The amplifier will not send energy to the speaker that will destroy or compromise it. This is open loop control. The amplifier cannot "know" the CE or VCT but it has been evaluated in the past in testing and the envelope has been built into the amp.

 

This leads us to score +1 for intelligent "unpowered" speakers systems. Actually the emphesis here is on the word "system". Good systems do not need the amplifier in the speaker box, neither do they demand the amplifier in a rack. For environmental reasons (water, wind, heat, safety, control, monitoring, ease of use) I prefer the electronics in a rack and the stupid bits in the black wooden boxes.

 

Also Rob (Beech) said...

 

"Thanks for that. I understand what you are saying with the advanced management. I suppose its one step up from returns and "sense" lines in such as the D&B subs. I think thats been mentioned either in this thread or somewhere else."

 

Well in terms of d&b remember that all the protection control is open loop. There is no (protection) feedback from the boxes. The sense drive back from QSub, JSub, B2, C7Sub allows the amplifier (Only D12) to see the voltage at the speaker, it can then compare this to the voltage at the amplifier and hence calculate the losses in the cable. This is a dynamic closed loop control system that effectively increases the damping factor of the amplifier/speaker system. The result is that a sub on 30M of cable sounds as punchy and controlled as a sub on 2M of cable. This is in addition to the level limiting, VCT and CE modelling metioned above.

 

edit... oh hang on, the older A1 amplifier configured to drive B2 also does the sense drive thing, sorry... like to be accurate!

 

+2 for intelligent speaker systems... "umpowered" in this case.

 

Cheers

 

Mark

[Simon Lewis]

Flying weight is often a big consideration with bigger active rigs. the meyer line arrays are damn heavy, cant be flown in all venues due to limitations of fly points and the like

 

Certainly true of the original M3D, but later offerings are much lighter, so I think this is case specific, rather than a general issue? Boxes like the Clair Brother's i4 seems to be bulky and heavy, but that's just me reading L&SI ;-)

[TAG1960]

I Have used Behringer B212's as conference speakers and find that they take very extreme eq-ing in the midrange to remove ringing. Personally these carpet covered boxes are not for me.

[Rob_Beech]

Hi Neil. (TAG1960)

 

Just a quick one.

Unless I've misunderstood the point you are making. The Behringer B212A (the op mentions 212 but speaks about the powered version) and all of that range are plastic cabinets, not carpet covered. In addition to this, the newer Behringer B1220pro and such are wooden boxes with a black vinyl type covering which is not very roadworthy IMO (although I don't mind the sound for a budget box).

 

The only Behringer boxes I know of which are carpet covered were the original ones, B1020 B1120 B1520 B1500x B1800x F1220 F1520 (don't quote me on the model numbers).

 

So all in all I'm not sure whats gone off there, unless they do a 212 carpeted I think you may have either got the wrong box in your head or some very rare limited edition ones :)

 

 

 

Rob

[TAG1960]

My Mistake Rob...It had been a long day in conference heaven yesterday...I was of course refering to b 1500s...I'll go back to sleep now!

[mi-ul]

My personal preference for larger rigs is unpowered speakers throughout. However for smaller rigs I like to run FOH as unpowered but for monitors having them powered allows you to take a rig without extra bits.

 

Do I need to take an 8U amp rack (nominal figures here) with FOH amp and 3 Monitor amps if I only need 2 monitors for a particular gig. I tend to do a lot of village hall work and the like, mainly accoustic work so for me having a FOH amp rack separate to monitor amps is useful and using powered monitors means I only need to take what is required for that gig.

 

Mi-ul

[Chappie]

As has been said before, I don't think there is an answer to this question, only opinion. Personally, I believe powered boxes do makes things a bit easier to cable up and every box is matched to its amp, with protection to match. It also means less boxes in the back of the truck, which is a substantial benefit to some people.

 

However, powered monitors do make a busy stage messy, with twice the amount of cables trailing across it, which is why we made the decision to run with unpowered monitors.

 

I also believe the rain/wind argument when doing an outside show is a bit of a non-starter. As long as the cabinets are designed to be weather-resistant and all your cabling is up to scratch you will not have any problems with water ingress.

 

As I said, no answer here, just an opinion.

[SteveAATW]

I think its like everything there are good and bad self-powered systems and sometimes cost inst a good guideline. Funktion One's first go at powered with the BSS in-built amplifiers were god awful, however the new XTA designed A4 & A6 are fantastic.

 

The various RCF range of powereds crop up all over the plae - for small portable systems they're probably the perfect product (though I've never been a fan of the RCF top heavy sound).

 

There are some fantastic un-powered alternatives out there though. People often cite combined weight in powrered's favour. When I was using Peavey CS, Crest CA, and MC2 MC series I'd of been inclined to agree. But with the advent of decent switchmode amps like the MC2 E series I'd now strongly argue against it. Not only does the E series weigh nothing, it sounds fantastic. d&b's DSP amps are also great, the d&b system control has always impressed me as a very well thought out product. For anyone who hasn't seen them yet - Bittner's DSP Amplifier range is superb - the fail over control especially is remarkable. Given products like these, and XTA DSP connected to a PC, the level of fingertip control you get over the system would make me hard pushed to argue in favour of powered's for any medium or large system.

 

For my pov, installing powered's in clubs has always been a no no for me - they're either in up against the ceiling or up against a wall. Everyone I've seen has at some point gone into thermal trip (though I haven't used the F1 A series in this way yet, apparently they'll work up to massively extreme temperatures) - one club I used to work at had powered RCF art 500's - some summer nights the system would be cutting out 5 or 6 times a night - completely useless. Another club had one of KV2's early powered systems, when it got hot if it wasn't cutting off it was blowing drivers. Then there's things like JBL eon - anyone who's ever seen a melted one (or had the misfortune to be subjected to the sound coming out of a working one) will hopefully stay well away.

 

The argument about less cabling is always a bit of a misnomer too I think for anything but small temporary systems. The mains cables for powered cabs will always be near enough as big as the speaker cables for non-powered. Plus you need to get the signal too them and the higher rated flying gear is going to add more weight for powered systems too. I don't know if anyone has ever done a TCO for owning a powered system but I'd be inclined to suggest its higher than unpowered. An integral amp may be matched to the cabinet, but if you know what your doing with unpowered systems then the amps in your rack will be matched to your unpowered boxes too.

 

Considering worst case scenarios too, you can swap an amp out of a rack backstage, you can't swap an amp out of the back of a cabinet thats 30' off the ground.

 

All comes down to personal choice, as with most things that make noise, but I don't think the products out there are yet mature enough to compete on a performance basis with un-powered systems. Most powered boxes I've seen always compromise something to get the amplifier in

[Chappie]

I don't think the products out there are yet mature enough to compete on a performance basis with un-powered systems. Most powered boxes I've seen always compromise something to get the amplifier in

I would stronly disagree with that statement. You obviously haven't looked at the right boxes!

[SteveAATW]

Always open to suggestions if you wanna point me in the right direction, can never hear too many speakers :)

 

But by performance I mean when put up against unpowered rigs consisting of XTA > MC2 > Funktion One cabs, d&b P1200/D12 > d&b cabs or XTA > Lab Grup > Martin Audio systems.

 

From what I've heard of the A4 & A6 amplifiers in the F1 gear the sound is pretty much the same, but they are more expensive.

[Rob_Beech]

But I think this is mainly because most of these manufacturers don't make powered boxes, so you cannot really compare. When we see the Q7A or the W8LC(P) then perhaps we can compare them to the unpowered versions of the same box.

 

I kind of understand what you're saying, but with all of the high end products its often personal preference to sound that plays as bigger part as whether they're "any good or not" as high end system wouldn't be that if they weren't any good.

 

Rob

[Trunker]

I think there are horses for courses. There are certain speakers I would for one job and others I would use for a different job. I like the KV2 systems for active (not cheap though at £1500 per speaker), and I like EV speakers for passive. Its all according on the gig, if you are on your own, how many flights of stairs etc. I wouldn't carry KVex2.5 bins upstairs on my own, whereas I could manage with an EV bin.

 

So no long and short answer, look at the gig!