I have a few things I'd like to clarify, please.
1. Inasmuch as I match the speaker-amplifier impedance or keep it very close can my amplifier take on any number of speakers? what is the limit? For instance, I have an amplifier that offers about 500W per channel and I have about 70 speaker (some are 16ohms 60W horns speakers others are 8ohms 60W cabinet speakers). I can find a way around series parallel calculation and wiring to make the impedance match but will it be safe? I am a little worried about the sound quality. Each speaker will be getting about 7W. Does that make sense?
2. For an outdoor setup, what do you think is the appropriate height for speakers? some say it should just be above the seated listeners' head. what do you think? Should it even matter if it is at the center?
3. What is the minimum distance at which a mic can be directly placed in front of a speaker to avoid the unpleasant loud noise?
4. From your outdoor speaker setup experience, can you suggest the most durable cable for low impedance speaker setup?
Thanks in advance.
Problems with outdoor speaker setup.
Re: Problems with outdoor speaker setup.
I think some of this was answered in your previous thread:
http://www.soundonsound.com/forum/viewtopic.php?f=26&t=54539.
#1 I'd think you'd be better of only using one type of speaker on each side of the amp, as you'll probably find a volume difference between the 16 & 8 ohm cabs. Also, make sure that whatever your series/parallel arrangement is, each speaker is wired in the same way or, again, you'll find volume and quality differences. Of course, it may be that you want it louder in some places than others, but ranging it that way it will start getting complicated very quickly!
#2 I'd try to get them as high as practical - within reason, the higher the better.
#3 Depends on a lot of things, like the type of mic, eq, volume you want. Impossible to put a figure on. Height of speakers will help here, as it's much more difficult to get too close to a speaker 4m in the air than one that's only at 2m.
#4 Thickest you can afford to avoid voltage drop in the cable, at the very least 1.5mm* and it really should be HO7 for outdoor use. Although you only need 2 core, 3 core mains is much more common, so usually cheaper. Some examples, though you may find cheaper if you look around:
http://cpc.farnell.com/pro-power/ho7rnf-3c1-5mm-50m/cable-rubber-h07rnf-3-core-1-50mm/dp/CB15514
http://cpc.farnell.com/pro-power/ho7rnf-3c4mm-50m/cable-rubber-h07rnf-3-core-4-00mm/dp/CB15518
Though for some reason, this 2 core is relatively cheap (note that's twice the length):
http://cpc.farnell.com/pro-power/ho7rnf-2c4mm-100m/cable-rubber-h07rnf-2-core-4-00mm/dp/CB15511
While I'm sure that you will get this to work, it's still a job that a 100V system is much better at, as you can just connect as many speakers as you want (up to the amp's power rating) on much cheaper cable.
* Changed my mind on this - see next post.
http://www.soundonsound.com/forum/viewtopic.php?f=26&t=54539.
#1 I'd think you'd be better of only using one type of speaker on each side of the amp, as you'll probably find a volume difference between the 16 & 8 ohm cabs. Also, make sure that whatever your series/parallel arrangement is, each speaker is wired in the same way or, again, you'll find volume and quality differences. Of course, it may be that you want it louder in some places than others, but ranging it that way it will start getting complicated very quickly!
#2 I'd try to get them as high as practical - within reason, the higher the better.
#3 Depends on a lot of things, like the type of mic, eq, volume you want. Impossible to put a figure on. Height of speakers will help here, as it's much more difficult to get too close to a speaker 4m in the air than one that's only at 2m.
#4 Thickest you can afford to avoid voltage drop in the cable, at the very least 1.5mm* and it really should be HO7 for outdoor use. Although you only need 2 core, 3 core mains is much more common, so usually cheaper. Some examples, though you may find cheaper if you look around:
http://cpc.farnell.com/pro-power/ho7rnf-3c1-5mm-50m/cable-rubber-h07rnf-3-core-1-50mm/dp/CB15514
http://cpc.farnell.com/pro-power/ho7rnf-3c4mm-50m/cable-rubber-h07rnf-3-core-4-00mm/dp/CB15518
Though for some reason, this 2 core is relatively cheap (note that's twice the length):
http://cpc.farnell.com/pro-power/ho7rnf-2c4mm-100m/cable-rubber-h07rnf-2-core-4-00mm/dp/CB15511
While I'm sure that you will get this to work, it's still a job that a 100V system is much better at, as you can just connect as many speakers as you want (up to the amp's power rating) on much cheaper cable.
* Changed my mind on this - see next post.
Last edited by MarkPAman on Wed Oct 05, 2016 11:46 am, edited 1 time in total.
Re: Problems with outdoor speaker setup.
OK - I'm not an expert on this, so may have something wrong!
But a quick look at some voltage drop calculators, shows a drop of about 70% for 1.5mm cable over 100m, which so not good for you at all. For 4.0mm cable it's only about 10%.
So I'd like to change my suggestion above to say minimum of 4mm cable.
Given that a 100V line system could happily use 1.0mm cable which is about £1 per meter cheaper, line transformers at about £5 each don't look so expensive after all. You will need time to fit them though!
How long are your speaker runs going to be?
But a quick look at some voltage drop calculators, shows a drop of about 70% for 1.5mm cable over 100m, which so not good for you at all. For 4.0mm cable it's only about 10%.
So I'd like to change my suggestion above to say minimum of 4mm cable.
Given that a 100V line system could happily use 1.0mm cable which is about £1 per meter cheaper, line transformers at about £5 each don't look so expensive after all. You will need time to fit them though!
How long are your speaker runs going to be?
Re: Problems with outdoor speaker setup.
Your biggest problem is not technical, it's that you're asking the wrong questions. You're trying do something technical, but you don't have enough knowledge of the subject to know *what* to ask.
So you could obsess over voltage drops and series/parallel and numbers of speakers and height of speakers, and all you'll get is details on the problems you're going to have. Or you could say "I'm planning on doing *this*. My initial thoughts are *that*. Please can anyone advise on whether there are better ways of doing it?" And then people here who've actually done this for a living (and I'm not one of them BTW!) can advise on how they've solved this problem in the past.
Put it this way. If I've just been asked to babysit an elephant for a week, my question to a zookeepers forum is not going to be "what temperature does it like its water to be?" It's going to be "holy crap, I've got an elephant to look after and I've never done anything like this before! Where do I start, folks?" With respect, you're in the second category for live sound.
So you could obsess over voltage drops and series/parallel and numbers of speakers and height of speakers, and all you'll get is details on the problems you're going to have. Or you could say "I'm planning on doing *this*. My initial thoughts are *that*. Please can anyone advise on whether there are better ways of doing it?" And then people here who've actually done this for a living (and I'm not one of them BTW!) can advise on how they've solved this problem in the past.
Put it this way. If I've just been asked to babysit an elephant for a week, my question to a zookeepers forum is not going to be "what temperature does it like its water to be?" It's going to be "holy crap, I've got an elephant to look after and I've never done anything like this before! Where do I start, folks?" With respect, you're in the second category for live sound.
Last edited by grab on Wed Oct 05, 2016 1:17 pm, edited 1 time in total.