Monitor speaker problems

rob aylestone

Moderator
I juist noticed we don't have loudspeakers as a forum heading anywhere? I'll post it here, but off there is a better place - mods, feel free to move it.

I have been mixing on the same set of loudspeakers since 1990. 28 years on one set of speakers - Celestions, if anyone is interested. I liked their sound then, and still do, and while they have a more traditional British sound, the important thing is that I never have to think about my mixes - I know what I hear, and I know it works on the kinds of material I work on, and where it gets played - which is mainly on stage. Think tracks really - for people to use for no band to full band purposes. I've blown one up this afternoon. I can buy new drivers (I popped the HF unit and it's dead and the LF driver now buzzes and vibrates and is very quiet, so I think a turn has probably shorted. My own fault - I swapped a drum VST for a new and untried one, and didn't notice I had prodded a solo button on the mixer I use to sum various devices, including the computer interface. I pressed play, and got nothing, so shoved up the master. Still nothing - the music playing dead space at the end of the song WITH THE LOOP ON. I spotted the solo and released it - still silence, so figured it was the rewatching I'd done, so I moved to the patch bay - and then the loop started the track, with everything on full and the big drum fill at the top of the song lit every red light going, and by the time I got to the faders, the right speaker was dead.

I can replace the drivers, but it means replacing both speakers, and of course the crossover is tired too, so do I start looking for a second hand pair that will sound exactly the same and mean no changes for my ears - or do I buy something more contemporary? I hadn't budgeted for this but I can probably stretch to whatever is needed?
 
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Which model of Celestions Rob and what are you driving them with?

I think you have done amazingly well over the years NOT to blow at least the tweeters! (I knew of a rig yonks ago with KEF Chorals and we had to fuse the tweeter because the Revox would make a "squark" once in a bluey when it came to FW rest.)

If the amplifier is as old as the speakers maybe start looking at actives? I know I bang on about it but the guys at SoS mag/forum WILL know of your Cellies and can almost certainly suggest something modern but similar.

I have promised myself a pair of Resluts 6s before I get too ga-ga to enjoy them! Not really for "stoodio" but just some fekking good speakers to listen to.

Dave.
 
Speakers are DL8's - and er, the amp is a RMX 2450, only about a year old - just one from the store 're-purposed' as it was available - hence why lots of level was a bit much! Normally the signal light hardly stops flickering at normal playback levels. A kick and snare the lit up red lights everywhere was kind of not just a tiny bit too far, but a huge bit too far!
 
Speakers are DL8's - and er, the amp is a RMX 2450, only about a year old - just one from the store 're-purposed' as it was available - hence why lots of level was a bit much! Normally the signal light hardly stops flickering at normal playback levels. A kick and snare the lit up red lights everywhere was kind of not just a tiny bit too far, but a huge bit too far!

WTF Were you thinking Rob? ! That amp puts out 450W at 1% distortion and probably sails way past 500W as it moved onto a copper melting square wave! The DL8s are rated at 150W.

I know there is a "camp" that says amplifiers should be rated over the power rating of the speaker, the "theory" being that a "clipped" amp can burn out tweeters. I personally have never subscribed to the notion. I believe you decide on the max SPL you need then choose the speakers then buy amplifiers based upon their sensitivity. MAYBE a dB or so of power in hand? I think "bigger than" always risk the well known 'it'Appenning and YOUR experience tends to lend credence?

There have been a few passives reviewed in SoS this last few months, can't recall them precisely but I do know one came with an amp and that was only 150W per ch!

Just a thought? How's you 'tronics DIY Rob? I ask because in Duggy Self's amp book he shows a circuit for a "clipper" but not the sort of crap you get in git pedals! No, this produces sod all distortion up to 0.1dB before the clip point then, WHAMMO! bugger all.

Dave.
 
Just happened to be sitting there - and was the lowest power amp I had in the store when the 100+100W amp that was in the studio got water in it from a leaking roof. I meant to replace it but didn't, and with the attenuators at a lowish setting, it seemed OK, and had been - on 24/7 as all the kit is - and it was just stupidity that the two channel and master fader got prodded - THEN the damn track started. I'm not interested in anything at all in the output. What comes out goes to the speakers. I want to keep it as simple as I can.
 
WTF Were you thinking Rob? ! That amp puts out 450W at 1% distortion and probably sails way past 500W as it moved onto a copper melting square wave! The DL8s are rated at 150W.

:laughings:

Sorry...had to chuckle.

Gutsy move Rob, but yeah, WTF were you thinking? :)
 
Unless you had everything panned to that side only, you might want to give the speaker that didn't blow (hmm) a critical listen, i.e., once your ears stop ringing (or, like me, it abates at least). Hard to imagine it didn't at least shorten the life of the other, so maybe get something to work with in the meantime and consider a project to recondition both of them at the same time, in the hopes they'll end up about the same place.
 
Unless you had everything panned to that side only, you might want to give the speaker that didn't blow (hmm) a critical listen, i.e., once your ears stop ringing (or, like me, it abates at least). Hard to imagine it didn't at least shorten the life of the other, so maybe get something to work with in the meantime and consider a project to recondition both of them at the same time, in the hopes they'll end up about the same place.

I agree Keith, both need to be done since the sides must match but, Rob will still have that monster amp and it is hard to see how to protect the speakers?

The drive to the amp (from?) could be attenuated such that 0dBFS only delivers about 150W but that still does not protect the speakers from any spikes that could get into the amp. Fuses are a possibility but the rating is tricky to arrive at (basically start very low and keep increasing until they don't pop for "normal" levels) The problem is there is some good evidence that fuses cause harmonic distortion as their resistance changes with the current through them. Not really what you want in a critical monitoring path!

I have had a bit of a look and I cannot find any passives, monitors or hi fi rated higher than 150W and most are lower, e.g. 75 to 150.

Dave.
 
It's not been a problem until I was stupid - and the way the attenuators are set, I normally have to push the faders well past halfway on the master for it to be too loud for normal use - in this case, the channels were well over the top, red lights pegged, AND the master was accidentally set full. I suppose I could just knock up a small in/out box that would stick in another 20dB pad, but it was stupidity here. In my pro PA role - we have a very large amp rack, and load it to suit the show. So we can run to 2Ohms on the sub amps without them getting stressed, but they're equally happy with an 8 Ohm sub load. I'd rather have spare undistorted amp capacity rather than worry when visiting shows tie into our system and push the levels up and up.

I'm quite happy with this kind of loudspeaker, as the bass end is pretty nice, and most of the small speakers don't sound nice to me. Temporarily, I've got some RCF M55s which I'll drag out for the meantime. They need fairly hard driving too - so the amp is pretty typical for them. I bet they sound naff though in comparison.
 
Guys - I'm, happy with the amp. I'm not looking at extra protection - I'm just very concerned that after all these years changing monitors is going to be painful. I can source new drivers from the states - which is odd considering they are British speakers, but after all this time I suspect that even new drivers will sound like different speakers so I may just have to get used a new 'sound'.

For what it's worth, I rarely follow rules, and in all these years have never had this happen before and really I guess I was just lazy, rather than any other reason. I am also the guy who NEVER switches phantom off, and when I get the crack through the speakers, still connect the last mic knowing that this fader too, is probably up. I'm also likely to unplug the PA speakers without switching the amp off first, and then running it like this for a few days before I remember. I'm an advocate of trying it first rather than over thinking why I shouldn't do something. I tell people I never turn the computers off because it makes them more reliable (to the annoyance of my colleague) when I just don't bother - especially as the electricity is his problem. I'm lazy, I take short cuts, but since 1984 this is the first real failure. My friend always says that if the equipment survives me, its good equipment - which could be true.
 
Ok Rob, if you can get new drivers then go for that. You will need to change all four.

The caps in the crossovers could stand changing but FCS don't fit foils in place of reversible electrolytics! That will FU the response. There might be burned out resistors as well.

I would fit fuses in your situation and live with the (probably theoretical) distortion. Basic math gives 4.3A ish for 150W and 8R but I would start with ONE amp fast fuses and see how things go. A 3.15A slo-blow takes about 10A to blow and quite a time to do so. Ideally I would have fuses in the woofer and tweeter circuits, the latter probably needing to be 250mA or lower.

Maybe you have some cat DNA?

Dave.
 
I tried Ebay, then somebody suggested Facebook - and there was a pair, described as tatty cabinets, in Norwich, which is 30 miles away. £35. I drove across and bought them this morning. They were in wood colour cabinets, mine are black and I didn't know wood finish was an option when new - but the only damage is the little protecting strips on one tweeter were broken and somebody has prodded the dome with a finger, but luckily - the other HF driver was fine.

I've swapped both the LF drivers and one of the tweeters, and it sounds like it did before. I would have preferred to have swapped the two HF drivers as a pair, but I cannot hear a difference with just one. So for 35 quid and a little fuel, I'm sorted. I've adjusted things a little so the loudest I can accidental drive the system has a touch more headroom - but I'm keeping the big amp. I just need to take a little more care with the mixer gains and levels. I tried a Behringer composer 2600 that was also in the store thinking maybe the limiter would be my safety net, but it does bring the noise floor up a tiny bit - so I will do without and risk it. I spent a fair time today looking for some monitors with more than a tiny LF driver, and they seem quite rare now - as soon as you go to 8" and above the price really jumps. The RCFs were too bright by a long way - good for PA, but they seem to be mid lacking - the bass is actually pretty good but the crossover point is quite high I think so they are a bit 'sizzle'.
 
Similar, but the tweeter is an aluminium dome, with a lightweight ally casting in front, in black that is more rectangular, with each side slightly curved. Luckily, I don't need to worry now I've got two functioning LF units. Pressing the speaker in on the faulty one has a slightly rough feel, so I suspect it over excursioned and the coil former is binding in the slot, which also would account for the lower volume. The other one is perfectly smooth and the duff one feels like it has sand in the slot - a roughness, but the coil measures the same as the other, resistance wise so the coil short idea I had was wrong. Probably fired forwards, and when the former went back into the slot it either grazed itself, or maybe some other foreign body got in?

Could have been far worse.

Thanks fellas!
 
Glad to hear you found replacement components for your old speakers. I've been mixing on the same pair of JBL L100s for about 40 years, I replaced the tweeters a few years back. everything else has held up quite well. Knowing what your monitors and room sound like is half the battle in mixing.
 
WTF Were you thinking Rob? ! That amp puts out 450W at 1% distortion and probably sails way past 500W as it moved onto a copper melting square wave! The DL8s are rated at 150W.

I'm in the camp that says more amp power than speaker rating is good. There are many anecdotes I can relate that support that (e.g. my engineering mate who used to drive a pair of 250 Watt EVs with a 1000watt Aussie Monitor amp).
 
I'm in the camp that says more amp power than speaker rating is good. There are many anecdotes I can relate that support that (e.g. my engineering mate who used to drive a pair of 250 Watt EVs with a 1000watt Aussie Monitor amp).

I run NS10'S rated at about 65 watts with a Bryston 3B running 150 watts each channel (300watts bridged mono)

Lots of headroom.
:D
 
I run NS10'S rated at about 65 watts with a Bryston 3B running 150 watts each channel (300watts bridged mono)

Lots of headroom.
:D


Do you fuse-protect on the speaker cables...or just watch your volume knob on the amp?
 
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