Hello there,
I'd like to have some basic info about certain aspects of live instrument monitors. What I know is that these types of loudspeakers are always subject to more air pressure than HIFI loudspeakers because they are always "fighting" against the pressure of the other sound waves in the room (Mostly drums and the other instrument amplifiers). This dampens their response quite a bit I think, right? In order to compensate for this they are fully sealed, so as to have the interior air pressure of the cabinet provide the opposite pressure, in order to re-equilibrate their response.
If I wanted to design a monitor cabinet with 10 inch drivers, in a cubic cabinet with a slanted front face (you know the typical monitor style), what should I be considering?
Some people have told me that 10 inch drivers won't suffice, but I'm not looking to push more than about twenty watts RMS into each at all times, well I guess that depends on the efficiency of the drivers. IS impedance a certain issue? I was wondering if the current required to drive monitor speakers is more than usual HIFI stuff, given that the counter electro-motive force required to move these coils is greater than the HIFI variety. So if I am planning to drive these with a regular Home amplifier which can't supply more than 5 amps, then maybe it would be better if I chose a 16 ohm driver, so as to reduce the current draw and make it easier on my power amplifier. Does that make any sense?
sorry for the long story.
I'd like to have some basic info about certain aspects of live instrument monitors. What I know is that these types of loudspeakers are always subject to more air pressure than HIFI loudspeakers because they are always "fighting" against the pressure of the other sound waves in the room (Mostly drums and the other instrument amplifiers). This dampens their response quite a bit I think, right? In order to compensate for this they are fully sealed, so as to have the interior air pressure of the cabinet provide the opposite pressure, in order to re-equilibrate their response.
If I wanted to design a monitor cabinet with 10 inch drivers, in a cubic cabinet with a slanted front face (you know the typical monitor style), what should I be considering?
Some people have told me that 10 inch drivers won't suffice, but I'm not looking to push more than about twenty watts RMS into each at all times, well I guess that depends on the efficiency of the drivers. IS impedance a certain issue? I was wondering if the current required to drive monitor speakers is more than usual HIFI stuff, given that the counter electro-motive force required to move these coils is greater than the HIFI variety. So if I am planning to drive these with a regular Home amplifier which can't supply more than 5 amps, then maybe it would be better if I chose a 16 ohm driver, so as to reduce the current draw and make it easier on my power amplifier. Does that make any sense?
sorry for the long story.
I don't think designers of stage monitors worry too much about counter forces from stage instuments. By the time you have enough energy coming out of them to compete with stage volume, spl at the throat of the drivers well exceeds any spl coming back at it.
There are many designs, but most are not sealed. Some are coaxial, some are WTW, some are the traditional woofer and horn above.
The selection of drivers depends on what they need to be capable of and the source material involved.
Some are just a 5" full range, some are a pair of 12" and a 2" horn.
There are many designs, but most are not sealed. Some are coaxial, some are WTW, some are the traditional woofer and horn above.
The selection of drivers depends on what they need to be capable of and the source material involved.
Some are just a 5" full range, some are a pair of 12" and a 2" horn.
This is one of those things where experience is a great teacher. You haven't actually told us much, but here's what I can tell you from my experience.
To compete with a hard hitting drummer, for a personal vocal monitor, you should have a 12" speaker rated at +95dB (for one watt) and at least 100 watts of power. As 12" speakers beam, it's nice to add a horn unless the singer stands stock still. For really loud rock/metal, you may need two 12"s. If the singer moves around, then you'll need several monitors across the front of the stage. If the instruments are run through large stacks and the drummer needs to be miked, then double the front and add 2x15" side fills with midrange horns.
A 10" speaker with 25 watts behind it isn't going to help if the speaker is on the floor and the singer is standing. Or, if it does help, then the band's not loud enough for the singer to really need a monitor (that doesn't mean however, they won't insist on one 😉).
Two 10" drivers have about the same surface area as one 12", so a 2x10 cabinet would work if the speakers are efficient enough. But if you're thinking of using hifi gear on stage with a band.... it's simply not robust enough. You need speakers with accordion surrounds that won't bottom out when someone drops a mike, and amps with big fans so they can run full tilt all night.
Now, with a few more details about your situation, perhaps we can be more helpful.
To compete with a hard hitting drummer, for a personal vocal monitor, you should have a 12" speaker rated at +95dB (for one watt) and at least 100 watts of power. As 12" speakers beam, it's nice to add a horn unless the singer stands stock still. For really loud rock/metal, you may need two 12"s. If the singer moves around, then you'll need several monitors across the front of the stage. If the instruments are run through large stacks and the drummer needs to be miked, then double the front and add 2x15" side fills with midrange horns.
A 10" speaker with 25 watts behind it isn't going to help if the speaker is on the floor and the singer is standing. Or, if it does help, then the band's not loud enough for the singer to really need a monitor (that doesn't mean however, they won't insist on one 😉).
Two 10" drivers have about the same surface area as one 12", so a 2x10 cabinet would work if the speakers are efficient enough. But if you're thinking of using hifi gear on stage with a band.... it's simply not robust enough. You need speakers with accordion surrounds that won't bottom out when someone drops a mike, and amps with big fans so they can run full tilt all night.
Now, with a few more details about your situation, perhaps we can be more helpful.
Thank you Keriwena for your help, you seem to be well informed in this subject. I guess you "rock" for real!
Well, at the moment, we are using my Traynor YCV-20 with one of those XLR-to-1/4 adapters. I put iton the clean channel, well that is I set the gain to 4 and the master to around 5 or 6, depending on the song we're playing. That's just a twenty watt tube amplifier with a 12 inch speaker, which we place at ear's height. It cuts through juts fine. But I want to play through that amp! So this is why I am considering using a solid-state receiver I have that is more powerful than my traynor, and use two monitor cabinets. That's waht I plan I building, not just one, two. That way we can orient them for optimal placement to all of us.
Anyway, Our drummer is not a super hard hitter, but crash cymbals are what really cut through, and you may guess he hits them often in a song, his snare has bite too, so that's more high frequency stuff, and our singer luckily doesn't have too much high frequency overtones in his voice. He's got really low, "manly voice"... uhh, sounds so wrong saying that! Anyway.
So I want to know basically if building two monitors with ten inch drivers will provide almost as much SPL as two monitors with twelve inches in them. Also I donT' really understand the need for accordion surrounds, although I have noticed that most professional and live sound speakers have this. My Dad's old Jensen 12 inch three-way speakers have this, and they were twenty watt (RMS) hifi speakers, back in 1970. The basis behind my desire for ten inch drivers is more to save space and weight than money. I want to be able to build a slanted cabinet that is no more than 12 inches high by 12 inches wide by 14 inches deep.
So that resumes what my goals are and what I have.
Thank you
Well, at the moment, we are using my Traynor YCV-20 with one of those XLR-to-1/4 adapters. I put iton the clean channel, well that is I set the gain to 4 and the master to around 5 or 6, depending on the song we're playing. That's just a twenty watt tube amplifier with a 12 inch speaker, which we place at ear's height. It cuts through juts fine. But I want to play through that amp! So this is why I am considering using a solid-state receiver I have that is more powerful than my traynor, and use two monitor cabinets. That's waht I plan I building, not just one, two. That way we can orient them for optimal placement to all of us.
Anyway, Our drummer is not a super hard hitter, but crash cymbals are what really cut through, and you may guess he hits them often in a song, his snare has bite too, so that's more high frequency stuff, and our singer luckily doesn't have too much high frequency overtones in his voice. He's got really low, "manly voice"... uhh, sounds so wrong saying that! Anyway.
So I want to know basically if building two monitors with ten inch drivers will provide almost as much SPL as two monitors with twelve inches in them. Also I donT' really understand the need for accordion surrounds, although I have noticed that most professional and live sound speakers have this. My Dad's old Jensen 12 inch three-way speakers have this, and they were twenty watt (RMS) hifi speakers, back in 1970. The basis behind my desire for ten inch drivers is more to save space and weight than money. I want to be able to build a slanted cabinet that is no more than 12 inches high by 12 inches wide by 14 inches deep.
So that resumes what my goals are and what I have.
Thank you
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a) It might be an idea to get a mod to move this thread, "Full Range" isn't really where it belongs
b) I work for a small live-sound company - at the moment, our go-to stage monitors are Turbosound actives - 12" with with a horn loaded compression tweeter, and 150W of power. They're capable of about 125dB at 1m. Generally, for rock gigs, 2 for the frontman, 2 for side fill. Usually another speaker for drum fill.
Stage monitors are nearly always sealed, but that has pretty much nothing to do with incident air pressure - just that extended bass response isn't terribly useful (bass from the room tends to find its way back to the stage just fine, and most of the bass is coming from sources behind the band anyway (drumkit, bass amp). Keeping them sealed allows for the cabinet to be roughly half the size of a ported design, which makes them cheaper, lighter and easier to carry.
I think you could get away with a 10" driver just fine, provided it was of sufficiently high efficiency (say 95dB/watt/m, minimum). If budget isn't a concern, I'd build two. The high efficiency rules out normal Hi-Fi drivers, you'll definitely need to look towards pro-sound drivers (JBL and Eminence drivers are easy to buy - that's not necessarily a recommendation, but it is a practical concern).
b) I work for a small live-sound company - at the moment, our go-to stage monitors are Turbosound actives - 12" with with a horn loaded compression tweeter, and 150W of power. They're capable of about 125dB at 1m. Generally, for rock gigs, 2 for the frontman, 2 for side fill. Usually another speaker for drum fill.
Stage monitors are nearly always sealed, but that has pretty much nothing to do with incident air pressure - just that extended bass response isn't terribly useful (bass from the room tends to find its way back to the stage just fine, and most of the bass is coming from sources behind the band anyway (drumkit, bass amp). Keeping them sealed allows for the cabinet to be roughly half the size of a ported design, which makes them cheaper, lighter and easier to carry.
I think you could get away with a 10" driver just fine, provided it was of sufficiently high efficiency (say 95dB/watt/m, minimum). If budget isn't a concern, I'd build two. The high efficiency rules out normal Hi-Fi drivers, you'll definitely need to look towards pro-sound drivers (JBL and Eminence drivers are easy to buy - that's not necessarily a recommendation, but it is a practical concern).
As TheSeekerr's response indicates, the answer to matching volumes on stage is surface area. In simple terms, because a 12" has almost twice the surface area of a 10" it will have almost twice the "volume", thinking of volume in the true sense of the space it fills with sound. I agree though, in your situation, 10"s might suffice.
Accordion surrounds act as variable rate springs - as they reach their limit they get stiffer. This causes compression, so they're not used in hifi, but for MI speakers it's like have peak limiting built in and reduces the chance of damage in the event of being overdriven. If a hifi speaker bottoms out, it's going to hit the end going full force.
Suitable speakers might be the Eminence Delta 10-A or their Kappa Pro 10-A.
And again The Seekerr is right, "easy to get" becomes a big concern if you blow a driver one weekend, and have a gig the next. 😉
Accordion surrounds act as variable rate springs - as they reach their limit they get stiffer. This causes compression, so they're not used in hifi, but for MI speakers it's like have peak limiting built in and reduces the chance of damage in the event of being overdriven. If a hifi speaker bottoms out, it's going to hit the end going full force.
Suitable speakers might be the Eminence Delta 10-A or their Kappa Pro 10-A.
And again The Seekerr is right, "easy to get" becomes a big concern if you blow a driver one weekend, and have a gig the next. 😉
Maximum volume really comes down to limits on cone excursion - a 12" can produce a given volume level with less excursion, so typically can go louder, because it can take more power before reaching the mechanical limits.
The accordion surround "compression" effect does have its dark side- while it's preventing the driver tearing itself apart, you're pushing a lot of power through the voice coil. I've seen far more drivers come back from hires with cooked coils than blown cones.
The accordion surround "compression" effect does have its dark side- while it's preventing the driver tearing itself apart, you're pushing a lot of power through the voice coil. I've seen far more drivers come back from hires with cooked coils than blown cones.
'Tis true.
So let's go back to the amp you'll be using. The reason PA systems use huge amps is because a clipped signal generates much more heat in the voice coil. And the distortion of a signal beginning to clip is not as audible as the distortion of a speaker reaching it's excursion limit.
This means if the amp is over-rated, then you'll hear the speaker break up and turn things down before damage is done. If the speaker is over-rated, there's a chance that the amp can get pushed to the point where's clipping the peaks and generating heat in the voice coil but it hasn't reached the point where it's distorting so much you're aware there's a problem.
Well, thank you both for your information, this is what I was hoping to hear. Well, I didn't know what you were going to say I mean, the way in which you relate the information is clear, precise, and makes perfect sense to me now.
About the suspension, I understand, very well explained, again! I guess that's why Cerwin Vega speakers were not considered HiFi in the eighties by certain audio magazines. They sure look nice though!
Now when you say the speaker can be damaged because the amplifier is clipping, it is because this audio signal contains many harmonics, and the high frequency harmonics can easily heat up a voice coil(of a full range or woofer), right?
I'm going to have to rent one of those powered cabinets for this weekend though...
About the suspension, I understand, very well explained, again! I guess that's why Cerwin Vega speakers were not considered HiFi in the eighties by certain audio magazines. They sure look nice though!
Now when you say the speaker can be damaged because the amplifier is clipping, it is because this audio signal contains many harmonics, and the high frequency harmonics can easily heat up a voice coil(of a full range or woofer), right?
I'm going to have to rent one of those powered cabinets for this weekend though...
It's not really the high frequency harmonics, but rather the very low frequency ones.
In the extreme case, clipping can result in an output which approximates a square wave - periods of positive DC rapidly followed by periods of negative DC, and so on. This results in power dissipation which is nearly 1.4 times higher than a sine wave of the same amplitude. This can be disastrous - say you're driving a 200W speaker with a 150W amp - push the amp into clipping, and it can suddenly be delivering sustained bursts of nearly 210 watts - this is bad for both the amp and the speaker, neither of which are built to deal with that sort of power.
In the extreme case, clipping can result in an output which approximates a square wave - periods of positive DC rapidly followed by periods of negative DC, and so on. This results in power dissipation which is nearly 1.4 times higher than a sine wave of the same amplitude. This can be disastrous - say you're driving a 200W speaker with a 150W amp - push the amp into clipping, and it can suddenly be delivering sustained bursts of nearly 210 watts - this is bad for both the amp and the speaker, neither of which are built to deal with that sort of power.
Thought I'd chip in.
I've used the Eminence Alpha 10 for various projects (first, it was a sub that didn't work, then I used it with a small full range driver, for higher SPL stuff). It has efficiency of 95dB, will take 150W continuous, and it's £35 over here (roughly $50 in USA, maybe less). I also know for a fact it will take some abuse - I used it to test a broken guitar amp, and it has 29vDC shoved through it maybe 3 times, more than 5 seconds each... still works now.
Seeing as bass isn't on the menu for these, it might be an idea to cross them over before excursion really starts. Also, make sure you low pass them at around 20kHz - I've heard of UHF (ultra-high-frequency) problems, where you get a feedback loop, but it's inaudible, because it's around 30kHz. Tweeters cook, so do amps.
Chris
I've used the Eminence Alpha 10 for various projects (first, it was a sub that didn't work, then I used it with a small full range driver, for higher SPL stuff). It has efficiency of 95dB, will take 150W continuous, and it's £35 over here (roughly $50 in USA, maybe less). I also know for a fact it will take some abuse - I used it to test a broken guitar amp, and it has 29vDC shoved through it maybe 3 times, more than 5 seconds each... still works now.
Seeing as bass isn't on the menu for these, it might be an idea to cross them over before excursion really starts. Also, make sure you low pass them at around 20kHz - I've heard of UHF (ultra-high-frequency) problems, where you get a feedback loop, but it's inaudible, because it's around 30kHz. Tweeters cook, so do amps.
Chris
Thank you all, good stuff!
I probably will opt for the Eminence Alpha 10. I imagine a regular inductor will do for filtering the HF?
I probably will opt for the Eminence Alpha 10. I imagine a regular inductor will do for filtering the HF?
If you make the box small enough (check the Eminence spec sheet and box design PDF) then it ought to prevent excessive excursion as long as it's not so small it creates a bump in the resonace. An additional -6dB from a cap wouldn't hurt, I suppose.
I suppose a single inductor would be sufficient. It'll only provide a -6dB/oct rolloff, but there 's a lot of octaves between audio and UHF. 😉 To be honest, though, I'm not aware of this as a standard practice. TheSeekerr? What you think?
I suppose a single inductor would be sufficient. It'll only provide a -6dB/oct rolloff, but there 's a lot of octaves between audio and UHF. 😉 To be honest, though, I'm not aware of this as a standard practice. TheSeekerr? What you think?
While it's not standard, I've heard of people cooking amps and tweeters with it, and, because it's so cheap to do (and won't affect the audio band), it's a case of "might as well...". A simple inductor of suitable small value will be fine. Even if it's a one in a hundred chance of happening, for a dollar (or whatever you guys use over there), I'd say it's worth it for peace of mind.
WRT enclosure size - you don't really need any bass from it, so, a cap would be worth while, especially if it does remove a hump further up the frequency range.
My latest project with the Alpha 10 is a guitar amp. At first, I used it with a 100W head, in an open backed cab (just for testing, you understand). Even when really going for it, excursion was fine. It's now in a 30W combo amp, where it will reside for some time...
Chris
WRT enclosure size - you don't really need any bass from it, so, a cap would be worth while, especially if it does remove a hump further up the frequency range.
My latest project with the Alpha 10 is a guitar amp. At first, I used it with a 100W head, in an open backed cab (just for testing, you understand). Even when really going for it, excursion was fine. It's now in a 30W combo amp, where it will reside for some time...
Chris
I wouldn't bother, to be honest - if you were using a tweeter with extended bandwidth, maybe, but the Eminence 10" doesn't produce all that much HF, so I struggle to imagine it becoming a part of an ultrasonic feedback loop.
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