norty303
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Posts posted by norty303
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QSC RMX2450 amplifier for sale.
http://www.qscaudio.com/products/amps/rmx/rmx.htm
Can supply pics on request (my web server is down at moment so can't link them)
£250 ono
Also have a 2U flightcase which i can do a deal on with this.
Pick up preferred due to weight but am happy to look at shipping if deal is right. Amp is in East Sussex.
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I've got 2 Futurelight DJ Scan 575 for sale. Used 3 times total from new, about 80 hours all in (2 clubs, one festival)
Still in original shipping boxes.
The current version of these is the DJ Scan 600 which is functionally the same but they changed the menu access from buttons to jog wheel on the 600. Otherwise all functions exactly the same so they can be used together with no problems.
http://cms.futurelight.de/index.php?option...wgtree=A0100170
7 different, dichroic colour-filtres and white
Rainbow-effect with adjustable speed in both directions
Gobo-wheel with 7 rotating gobos, open and blackout
Strobe-effect with adjustable speed via shutter
DMX-controlled operation or stand alone operation with Master/Slave-function
Effect-wheel with rotating 3-facet-prism, 4-facet-prism, 3D-prism and 9-facet-prism
The prisms rotate in both directions and at different speeds
Sound-controlled via built-in microphone
Control-Board with LCD-display and encoder for adjusting the DMX-starting address, Pan/Tilt-Reverse
Motorized focus
Blackout-socket
For extremely bright 575 W HMI-lamp
DMX-control via every standard DMX-controller
I've got some photos that i took at the weekend to put up when i get my new PC FTP sorted.
At the festival we used these with some Mac500's and they absolutely blew the Mac's away in terms of brightness.
They are 24kg each without packing so are probably a bit big to post, but might consider it.
Thomann charge just under £500 each, with lamps an additional £70.
Looking for £700 for both.
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Be careful with 400w UV cannons in small venues. they can cause arc eye in the same way that regular high power lights can. If you do use them, make sure they are up nice and high and not directly in peoples eyes
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Try connecting a 9v (PP3?) battery across the terminals and see if the cone moves. If it doesn't and the tinsel leads are still intact and connected then it's likely the voice coil has become damaged.
At this point i'd cut the cone out to see what went wrong if it was me...
Probably worth reconing considering the price of a new driver, although there are better out there for the money.....
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You cannot make blanket statements about brands I find.
It all comes down to the specific items design brief and whether it happens to have been one of the good 'uns or bad 'uns.....
Behringer is a favourite to bash so i'll use some examples...
DCX2496 Ultradrive - without a doubt THE best LMS on the market below £500 (and then some). Teathing problems with first batches caused by poor IDC headers put some people off, but they have impressive specs, good sound quality (better than some 'better' brands in much higher price brackets) and an intuitive user interface.
'Composer' range of compressors - not exceptional sounding but again, you've got to spend a lot more money to better them. Many hire/PA firms still use them exclusively in their 'B' rigs and have done so for many years. Dependable but cheap enough to carry spares. Earlier ones are often considered nicer sounding before they added all the digital stuff
XM8500 mics (and XM2k's) - cheap copy of the SM58 but with some refinements that people actually prefer to the SM58. Certainly you can get 3 for the price of Shure and they're robust too.
But again, they also have their dogs (some of the EQ's, not nice sounding, poor fader reliability, etc) I think one of the reasons why you read more tales of failure is simply that there's so many more of the units out there.
I would advocate spending money on decent 2nd hand gear over new stuff thats of lesser heritage. It should last well being a good brand, it will devalue less (some hire company has likely taken the initial hit on depreciation) and it will have a better support package in place should something go wrong as they are in the business of keeping critical gigs running, whatever the circumstances. QSC had an amp turned around and back in a friends possession within 3 working days, inc shipping time.
Buying this sort of kit also means that you should have no problem moving it on when you're done with it, as it's still desirable. Martin audio modular systems still fetch good money on ebay despite being some decades old now.
I've recently sold some of my bass bins as empty cabs and drivers separately. The Precision Devices drivers actually sold for MORE than i paid for them new after having them for 2 years!
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Just to summarise some basic knowledge about horn speakers compared to reflex and other types.
If a horn is too small for the frequency it is operating at (an acoustic mouth circumference much less than about 1 wl), then placing it next to an identical unit will normally extend the low cutoff.When the area ratio between the mouth and throat is not large, the low cutoff of the horn is set by the ¼ wavelength resonance and in this situation the resonance is roughly set by the length of the horn path.
While a horn is not at maximum efficiency until it is ½ wl long or longer, it can provide usable output (significant gain over the same driver not horn loaded) down to about the ¼ wl resonance and at much lower frequencies, only has the output of a sealed box (the driver, its compliance and back volume).
The quarter wavelength resonance is the lowest mode a pipe closed at one end and open at the other resonates at, for a pipe to resonate at the same frequency with both ends open (½ wave length resonance) it has to be about twice as long.
In a horn, as the mouth area becomes larger, some of the air out in front of the horn is still governed by (highly coupled to) the pressure gradient at the mouth and so is an acoustic length added to the horn path length. How much it adds to the length depends on its shape with round or square (including the mirror image) being the best and typically adding about .6 to .8 times the horn mouth radius. A large mouth can add significantly to the path length and can have a significant effect on the low cutoff.
Basically, if you want a good useable range from a small number of cabs then go for the reflex/bandpass option. Horns that are efficient low down tend to be very large if single cabs, or be made up of multiple smaller elements to achieve the required mouth size to support the wavelength of the lowestt note played.
Going back to the 250hz thing, one of the other issues with playing horns up high is what they describe as 'honk'. This is where the folds in the horn start to become too acute for the ever lessening wavelength of the note as the frequency rises, causing back reflections and other nasties. Internal smoothing and utilizing less acute angles helps, but then the cab size grows due to the undesirable folding pattern. Tony Andrews went to some great pains with phase plugs in his Resolution series low mids to get over this. His patent papers make for some interesting reading.
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I'm sure Tony Andrews will be glad to hear you say that 250hz is too high to crossover from bins to mid-hi packs,as thats exactly where the Turbosound TSE series of concert cabs did x-over
Oh ok, we'll compare every generic reflex speaker against a well designed horn setup with well researched characteristics running actively then. :)
Most cheap 18" reflex bass bins are not designed to produce low mids well as it requires a lighter cone structure. The manufacturers tend to go for boom by using a heavier one, and something gets sacrificed. Using a 15" mid (or a decent 12") you are better having the kick region in the faster cone. Due to the high excursions in bass bins/subs, the narrower the bandwidth the better i find for sound quality.
The Turbo gets this by being a horn which tend to have better dynamics in this respect. That said you'll need a few of the TSE's to get as low as the reflex will do in singles or pairs. The horn path and mouth aren't big enough in singles to do the job.
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I think it depends on how powerful you want your sub to be.
Once you get over around 500w power handling the cost of a passive network becomes prohibitive compared to an active solution. If you want a passive solution at all costs then the sky is the limit, but at some point you might want to look at some of the dedicated 3 channel amps (or 4 channel with a pair bridged giving 2+1 channels) designed to do exactly this sort of thing, normally with built in DSP to do the filtering.
Eminence do a PX250 low pass filter for around £35 which might do the job, however 250hz is a bit high for a sub if you ask me, I'd be looking for something nearer the 150hz range.
BTW if you Google 'passive low pass filter' you'll get a variety of sites giving DIY solutions. If you come over and ask the question at www.speakerplans.com/forum I'm sure one of our members will be more than willing to guide you on your way.
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another way to avoid the muddy bass is to run them full range but run the tops out of phase.
Well yes, it'll avoid the muddy bass because its a really effective way of killing the bass frequencies dead! Given all of the phase checking tools on the market, generally most sound companies do their best to avoid reversed polarity drivers.
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I'd say you are playing frequencies below the port cutoff frequency and the driver is unloaded. Get something like a behringer ultradrive and add a high pass filter just below the tuning frequency of the cab. I'd take a bet they'd go louder then and still sound ok doing it.
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Ah, the old halogen vs led debate again!
The problem when comparing led's vs regular pars is that its often done on open cans which the led's will never compete with. However on very saturated colours such as deep blues and reds, the LED's often come out on top.
The regular pars win by virtue of the fact they have a much better beam control unless you start to get into very pricey 1w or 3w led cans.
The 5mm and 10mm cans are ok for smaller gigs (or discos) and are very useful for eye candy/environment lighting. Be warned about the 10mm ones from Eurolite if you're using them for lighting into the crowd. The leds are arranged in concentric rings so are less 'nice' to view head on than the ones with evenly distributed leds
HOWEVER, in the last month or so Thomann (Stairville) and Eurolite have released affordable 1W LED cans, each with 36 1W led's. the Stairvilles are about £110, the Eurolite (in a smaller, neater housing) for about £140. The only thing these seem to give away over more expensive 1W cans is the even balance of the diodes (12 of each colour) Thje more expensive ones tend to have a higher number of blue (or use 3W diodes) in order to maintain a reasonable white balance. That said, for discos, do you really care?
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Well diffraction gratings have been used as effects in lasers for a long time and I've yet to see any sort of documentation to say that they make them safe. They may split the power present into many smaller beams of lower power but until you measure those beams, you can't be sure they're below MPE individually. I'd recommend contacting the manufacturer and see what they say, or try asking the question about diffraction gratings and power on Photonlexicon. You'll get some quite in depth responses I'd suspect.
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Yes the amp is a bit big for the speakers but you don't have to run it flat out. With the cheaper end of speakers particularly, they're fairly good at letting you know when they're being pushed as the sound quality deteriorates fairly badly (well worse than where it started from at least :P )
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Class 3b lasers are easily capable of causing eye damage.
All lasers of class 3b and above should have a keyswitch to prevent unauthorised use by untrained personel.
If you can't prove that your laser is below the permissible MPE when scanning each of its patterns then you shouldn't be scanning the crowd.
There are probably quite a few threads now where people have asked about lasers and crowd scanning and some knowledgable people have given good responses.
Try some keyword searches, and perhaps for posts by Jimbo (Jim Boylan) for some good responses.
Its such a huge area that the issues become very complex, but is one of the reasons I don't like lasers being sold as disco effects. The low powered lasers of today were the moderate sized pro lasers of a few years back.
If you want to read up on some very interesting and informative discussions on laser use and crowd scanning, try visiting the following forum where you'll get some very good advice and technical info
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Funnily enough one came up on ebay in the last couple of days.
Might be worth a punt if you're quick
http://cgi.ebay.co.uk/Martin-Atomic-Strobe...id=p3286.c0.m14
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The Pulse's are fine amps for mids and tops but lack the grunt for bass applications due to the early weedy switch mode power supply by modern standards. There was a mod for the PSU which fixed completely the earlier faults and you can still get it done no problem today.
I know of a few sound systems that still use the Pulse preferentially over anything else.
Another amp to be considered these days is the Tapco J2500. Very similar to the Berry amp (and obviously shares the same sort of layout as the QSC RMX series as you'd expect) but with a larger PSU. Tests indicate that of the budget amps, this seems to be the one that gives most bang for buck and they seem nice and solid.
As for the 606/707, there's still a lot of them out there in use and they do pack a punch, even if their rated watts are not as high as newer amps. This is because modern amps tend to get rated with short bursts which don't really give a good indication of how they'll perform on modern bass heavy music.
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Hi Tony
Is that the Dimension series of amps? If so, they also only use Ch1 input and controls when in bridge mode.
Which Crown amp has the Y input as that sounds like it may have a sum option?
Edit:
Actually the text is quite confusing in the manual as it says to connect input signals but then goes on the say you only use the Ch1 controls. I wonder if the 's' on signals is a typo or whether it does some sort of re-routing internally? Easy way to test would be to plug in Ch2 onluy and see if there's any output, or unplug one whilst in operation and see if the level drops.
Stereo/Bridge Mode Switch- Bridged mono operation is easily achieved and gives you the output power of bothchannels with just one mono output. For successful bridge operation, follow these instructions:
• Set the Mode Selector to Bridge while amplifier is off.
• Connect input signals.
• Use only the middle terminal post outputs for speaker wiring, or middle speakon output. Connect the speaker
load to the red terminals of each channel. Please confirm the (+) terminal of speaker to Channel A and the (-)
terminal of speaker to Channel B. Do not use the black terminals of each channel.
• The minimum load impedance in bridge mode is 4 Ohm.
• To adjust level, use Channel A control and leave Channel B level at zero.
• To use a subwoofer, make all setting adjustments on Channel A.
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Using one passive bass bin does have the problem of getting bass from both channels to feed it.
One option is to use an amp in bridge mode
Hi Tony
Can you explain if you mean that an amp in bridge mode is a solution to getting a summed signal into it, or were you referring to simply powering the cab in bridge?
With every amp I've ever come across, when you put them into bridge mode, only one of the inputs works. Sometimes the other one becomes an output that can be controlled via the ch2 gain knob but I've not seen one that sums the 2 to the single channel. The significant thing about bridge mode is that it is a mono output so will require a summed signal to be generated at some point before the amps input, e.g. at the mixer or active crossover.
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Does it have a passive crossover/filter inside it? If not, you'll need an active crossover in your system.
If it has the option to pass through to a mid top I would advise against it with a single sub as your tops will become inbalanced power wise. Use a dedicated amp for the sub, either just using one channel, or bridged, depending on the power you want to put into it. If you're using the correct filters etc then i'd say anything between 1x and 2x the rms rating of the cab. Others will now offer their opinions on this. However, if you wish to make the most of your single sub you WILL need to drive it with more than the RMS rating (which IS safe to do if done correctly)
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what do you mean by 'set up'? With a single bin the only option really is room placement. If you need as much bass as possible then you really need to place it in a corner or at least against a wall. This gives a higher loading due to the more confined space and can give very noticeable gains in some rooms.
If you had 2 bins then the options become more complex but I'm not sure there's too much to get wrong with a single bass cab. Find out what it's -3or -6db point is on the low end and makes sure you use a high pass filter around this area. This way you'll get as much boom out of it for your (amplifier) buck and reduce the risk of breakages due to over excursion. You might want to play around with the crossover frequency to your mids and see what sounds nicest. some subs punch well and so like to be crossed higher (150-250hz) and some don't sound nice above 100hz. Don't go on a spec that says 40hz-400hz, this is not indicative of its intended range of use, just that it will make noise in this bandwidth.
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Funnily enough, the country of origin of the rig can influence this sound quite a lot.
In the North American market where the predominant music tends to be rock gigs, they like(d) a very forward sounding upper mid which is why JBL and others stuck with large diaphragm 2" compression drivers whilst european manufacturers started to look at smaller format comps over paper cone mids (6.5" or 8" typically) or most recently Funktion 1 with their impressive 5" mid and high device.
I run 2" comps and whilst they have a lovely snap to them, its VERY easy to overdo them in the 5-6khz range. They do throw for miles though!
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Distortion also creates a perception of loudness, particularly on the bass end. When you have a very clean sounding rig its often quite surprising how loud it is when you meter it compared to a (seemingly) really noisy distorted one.
I often wonder if DJ's/engineers have had an ear transplant when you hear just how nasty sounding and cutting the high mids and tops are.
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The other good benefit of a horn is that they are bandwidth limited, meaning that they play very efficiently in a narrower bandwidth than conventional speakers and roll off very quickly either side of this (bandpass subs work the same way) This means they act as very efficient filters for some of the unwanted noise artefacts produced by cone speakers, especially when driven hard. The downside is its harder to tell when you're near the mechanical limits, meaning failures can happen suddenly. Also some people tend to not like the characteristic sound of a horn.
But in relation to the original question, you could then advertise your rig as '4k, but louder and nicer sounding than his 4k!'
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Also don't forget that 2 identical rigs, one with 2k of amps and one with 4k of amps, the 4k is only ever going to be 3db louder (maximum, power compression at high levels will remove a good chunk of that) although the one with 4k will probably sound fuller and more dynamic and generaly nicer.
Keeping the 2k amp and switching your speakers for nice horns would make the biggest difference.....
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Oh god, infamy is a terrible thing! :)
I hear you're enjoying your ASS (insert 'fnar fnar' comments as needed...)