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What size Amp?

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SnailSpace View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SnailSpace Quote  Post ReplyReply Direct Link To This Post Posted: 10 December 2022 at 11:25pm
Found this a good video, after what you’ve been telling me starts to make more sense!

So I came in and powered up just the Jamos and put on ‘Jimmy Riley - Live It To know it 1975-1985’ and now kind of get why they may confuse the crossover as they probably also have a built in crossover and being the mid section as they are really a bass/mid/high unit in themselves. Any way they are nice as a x4 so it will be interesting as the bass isn’t really bass it’s more mid ha! Anyway it gets me on the right track! It’s starting to make sense as I’ve never really over examined it in this way until splitting boxes into there own job!




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Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2022 at 9:48am
Originally posted by SnailSpace SnailSpace wrote:

Just put it into the calculator and you’re right I looked in the wrong place at 2 speakers instead of 4, 4 said it would be a 1ohm output.

What speakers would you use in bridge mode?

So what type of Series configuration would I be looking at setting up?

Had a look at ART SLA1 & SLA2 thanks (and again was searching something else) out of the need to learn again and the fact they are around £300 - why would I choose this type of amp over something a touch bigger but cheaper if so what would the outcome be? Is it so I’m not over working the amp or the tweeters? 

Cheers



You needed a calculator to work that one out!!??!!   Smile LOL Smile

You need to connect:--  amp +ve  -> speaker +ve. Then speaker -ve to next speaker +ve and finally speaker -ve back to amp -ve.

Then repeat for the other channel/pair of speakers, ie. each cabinet will have 2 drivers, with the +ve of one connected to the -ve of the other, with the other contacts going to the amp. Fairly simple...   


And simplifying a bit, you use bridge mode when the driver/s you have are capable of handling a lot more than the amp provides in normal stereo mode. Or a way amp manufacturers use to exaggerate the specs of their amps!   LOL LOL LOL

The ART amps are obviously on the high end of the market. For something a bit more reasonable, but still reliable maybe look at the Thomann amps (T-Amps) or even the Behringer stuff, etc. Or something second hand from QSC, Crest, Peavey, etc., etc.


EDIT:- The video there shows the basic features of the DCX. All available from the front panel. No need to connect to a PC.  Thumbs Up





Edited by Earplug - 11 December 2022 at 9:52am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SnailSpace Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2022 at 12:59pm
Cheers Thumbs Up

This calculator ha Big smile


I still feel like I’ve decided take on a physics project rather than upgrading sound equipment Smile
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2022 at 2:27pm
Ok, a picture is worth a 1000 words!!

And a B.Sc in Rocket Science does help! LOL


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Post Options Post Options   Thanks (0) Thanks(0)   Quote SnailSpace Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2022 at 2:51pm
Don’t get me wrong even using that calculator I’d be lying if I said I understand why 4x 4 ohms speakers in parallel give you an impedence of 1ohm and not four?  

Unfortunately for you I’m that student that takes x29 explanations or an epiphany for something to make sense!

I find Audio University are good videos, but this forum and yours ended have been great for giving me the time for the Penny to drop!

What type of Sound do you have yourself and what do you use it for?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2022 at 6:18pm
Originally posted by SnailSpace SnailSpace wrote:

What speakers would you use in bridge mode?
Forget Bridge mode... it's usually the least desirable amp config to use.

Originally posted by SnailSpace SnailSpace wrote:

So what type of Series configuration would I be looking at setting up?
I'd also suggest avoiding any series connections unless they are inside a cab, externally wiring drivers in series requires specially wired speaker cables which are way to easy to mistake for parallel wired cables. But that bring up an interesting option, can you put 2 15's in a single cab or is everything built already?

Originally posted by SnailSpace SnailSpace wrote:

Had a look at ART SLA1 & SLA2 thanks - why would I choose this type of amp over something a touch bigger but cheaper
Well you don't need something larger for tweeters and it's about sound quality. Class D amps can certainly get the job done but for a little more $$ you get less noise and smoother sound. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Daniel S Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2022 at 8:42pm
Originally posted by SnailSpace SnailSpace wrote:

Don’t get me wrong even using that calculator I’d be lying if I said I understand why 4x 4 ohms speakers in parallel give you an impedence of 1ohm and not four?  

Unfortunately for you I’m that student that takes x29 explanations or an epiphany for something to make sense!

I find Audio University are good videos, but this forum and yours ended have been great for giving me the time for the Penny to drop!

What type of Sound do you have yourself and what do you use it for?

When calculating total impedance for a number of speakers of the same impedance wired in parallel, you take the impedance and divide it by the number of speakers. In this example 4÷4=1. Four 8 Ohm drivers would be 8÷4=2.
When wired in series you add the numbers, ie 4+4+4+4=16
You can get an 8 Ohm load with 4*4 Ohm speakers by wiring two and two in series and then wire those in parallel to get ((4+4)+(4+4))÷2=8.



Edited by Daniel S - 11 December 2022 at 8:44pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2022 at 9:08pm
Originally posted by Daniel S Daniel S wrote:

You can get an 8 Ohm load with 4*4 Ohm speakers by wiring two and two in series and then wire those in parallel to get ((4+4)+(4+4))÷2=8. 

You messed up something there because two 8ohm loads in parallel = 4ohms. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SnailSpace Quote  Post ReplyReply Direct Link To This Post Posted: 12 December 2022 at 10:09am

Originally posted by SnailSpace SnailSpace wrote:

So what type of Series configuration would I be looking at setting up?

Originally posted by Conanski Conanski wrote:

I'd also suggest avoiding any series connections unless they are inside a cab, externally wiring drivers in series requires specially wired speaker cables which are way to easy to mistake for parallel wired cables. But that bring up an interesting option, can you put 2 15's in a single cab or is everything built already?

Already have boxes I have x4 15” 150w as well as the PV’s as I say I may at later date make boxes but one step at a time. 

Interested to find why you say don’t use series when earplug reccomended series and you said don’t link in parallel as the amp would immediately shut down?

So I presume you’re saying only option left is Stereo and surely that means I have a lot of wires feeding back to amps?

When ever I’ve looked at the back of stacks at sessions I’m sure they are linked in parallel or series? Ie linked by one short external cable to each speaker from the other on each section then one cable heading back to amp? Or are they as you say wired different inside rather than just + & - terminals.

Are you and Earplug coming from different disciplines meaning different preferences or are you basing your advice on what I have and its capabilities? (I understand what I will be using as mids x4 Jamos are passive speakers and I’m currently reading up on mixing Passive & Active speakers and seems to be ok, not ideal but as I say this is the first steps. Custom boxes/additional speakers/moving around will be another step)

I want a one stack approach linked by short cable runs with limited longer runs going back to the amp if possible.

Tweeter box - ART Amp or similar (split off & boxed as - active) 
Mid - Jamos x 4 (ok not ideal as they are - passive) QSC GX3 Amp
Bass - BW PV’s x 4 (again not really bass but again boxed as - active) Amp QSC 3602 PLX or similar

Crossover


Edited by SnailSpace - 12 December 2022 at 10:52am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 12 December 2022 at 1:43pm
You have missed/misunderstood the most important bit:-

"I'd also suggest avoiding any series connections UNLESS THEY ARE INSIDE A CAB, "

So I'd suggest 2 x 2x15" cabinets, with the speakers wired in series inside.

Then 2 cables going back to the amp. One per channel, normal stereo mode. Look at the diagram in the calculator link you posted earlier. It's all there.   Confused


And I don't think that Mr. Conanski will disagree there. We are both saying the same thing, albeit in a slightly different way. Canadian English v. The Queen's (King's?) Thingie!  LOL



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Post Options Post Options   Thanks (0) Thanks(0)   Quote SnailSpace Quote  Post ReplyReply Direct Link To This Post Posted: 12 December 2022 at 1:54pm
Yeah missed that bit where you also suggested avoiding series too.

I don’t have option of putting x2 15” in one cab for now. 

So does this mean I’m stuck with connecting in stereo as my only option and multiple wires heading to the amp ie a +- from every speaker? So x8 wires from x4 PV’s to one amp, X8 from x4 Jamo to their amp? 

I’m still confused to why Series/Parallel/Bridged aren’t an option if I have correct Amps?

I thought you could wire speakers in series/parallel outside the box? Is this where I’m confused, do most sound systems link within the boxes? So what are the linking cables I’m seeing on the outside? For me I’m trying to limit the amount and long runs of cables on the outside back to the amp or does what I have not allow for that?




Edited by SnailSpace - 12 December 2022 at 2:03pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 12 December 2022 at 3:39pm
Originally posted by SnailSpace SnailSpace wrote:


you said don’t link in parallel as the amp would immediately shut down?
 
I said you can't connect 4 speakers together in parallel. You need to slow down and read more carefully because the small details matter. 

Originally posted by SnailSpace SnailSpace wrote:

So I presume you’re saying only option left is Stereo and surely that means I have a lot of wires feeding back to amps?
No just 1 +/- pair per channel.

Originally posted by SnailSpace SnailSpace wrote:

When ever I’ve looked at the back of stacks at sessions I’m sure they are linked in parallel or series?
They are almost certainly linked in parallel. 

Originally posted by SnailSpace SnailSpace wrote:

(I understand what I will be using as mids x4 Jamos are passive speakers and I’m currently reading up on mixing Passive & Active speakers and seems to be ok, not ideal but as I say this is the first steps.
Active speakers have an amplifier built in and as far as I know you don't have any of those. Those Jamos are 3-way fullrange passive speakers correct? Do the mid and high drivers still work?

Originally posted by SnailSpace SnailSpace wrote:

I want a one stack approach linked by short cable runs with limited longer runs going back to the amp if possible.
Should be possible. The easiest way to do this is to put all the amps in 1 rack with the crossover/DSP and place it behind the stack, then connect 1 speaker cable from each amp channel to a box and put a short jumper between it and a second box of the same type. 


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