I'm building some MTMs. My receiver says it is rated for 6-16 ohm loads. For the sake of discussion, let's assume that's true.
So I have 2 mid/woofs, Re 6.2 ohms each. I can:
1. wire series and get 12.4 ohms
2. wire parallel , get 3.1 ohms and put a 3 ohm resistor in series.
I know the series resistor wastes power, but it is still presenting just half the impedance to the amp, so wouldn't it be more efficient? i.e. greater SPL?
OK, now I'm sitting here with 12 of these mid/woofs, so don't tell me to just get 4 ohm drivers, thanks, or to just make them MMTMMs. The question is would you do 1 or 2 and why?
Oh, yeah, one other thing. I'm planning on a zobel for these. I know how to do it for the series, but I'm wondering if I couldn't put it across the outputs of the XO if I do parallel, basing it on the 3.1 ohms? Or do I have to put one across each driver's terminals?
TIA
MB
So I have 2 mid/woofs, Re 6.2 ohms each. I can:
1. wire series and get 12.4 ohms
2. wire parallel , get 3.1 ohms and put a 3 ohm resistor in series.
I know the series resistor wastes power, but it is still presenting just half the impedance to the amp, so wouldn't it be more efficient? i.e. greater SPL?
OK, now I'm sitting here with 12 of these mid/woofs, so don't tell me to just get 4 ohm drivers, thanks, or to just make them MMTMMs. The question is would you do 1 or 2 and why?
Oh, yeah, one other thing. I'm planning on a zobel for these. I know how to do it for the series, but I'm wondering if I couldn't put it across the outputs of the XO if I do parallel, basing it on the 3.1 ohms? Or do I have to put one across each driver's terminals?
TIA
MB
Definitely go with series (12 Ohms DC). The amp will be much happier. You are gaining efficiency by adding the second woofer, so dont worry about the high impedance.
There will be more distortion at 6 ohms and you are dropping half your power on a resistor.
And do one zobel for the measured impedance curve with the drivers in series.
There will be more distortion at 6 ohms and you are dropping half your power on a resistor.
And do one zobel for the measured impedance curve with the drivers in series.
Agree with series although be aware that the speaker DC resistance (Re) is not really what you should be looking at from a 'rating' point of view. That is an 8 ohm sppeaker you have there so parallel would give you 4 ohms impedance.
Using parallel then adding a resistor to bump up will totally change the damping of the speaker for the worse.
Using parallel then adding a resistor to bump up will totally change the damping of the speaker for the worse.
another question
okay, so I have a similar dilemma. I am wiring a 5.1 surround system. I have four 8 ohm small tower speakers that are identical. I would like to use one for L, one for R, and two for the center channel, w/ some smaller bookshelves for surrounds. I have a standard surround 55 X 7 HK receiver and an audiosource amp one/a (80W X2 bridgeable to 200 W). I can use either the HK or the outboard audiosource for this application. Keep in mind the HK amps will still be driving at least the rear 2 channels and possibly the front L and R.
I can wire the two identical speakers in a number of ways. I could:
A. Run them in parallel either w/ one channel (better idea) of the audiosource or in bridged mode (probably not a good idea). I could also use the center channel of the HK for this. Of course, this means the HK would see a four ohm speaker on the center channel, which may or may not be a problem.
B. Run a splitter before the audiosource and then simply run each speaker from the standard outputs.
C. Bridge the audiosource amp (or not) and run the two speakers in series. This way I would have 16 ohms, and the amp, being bridged, would see half of that (8). This seems like the best option--however, I read this online:
Please help--any input would be greatly appreciated.
okay, so I have a similar dilemma. I am wiring a 5.1 surround system. I have four 8 ohm small tower speakers that are identical. I would like to use one for L, one for R, and two for the center channel, w/ some smaller bookshelves for surrounds. I have a standard surround 55 X 7 HK receiver and an audiosource amp one/a (80W X2 bridgeable to 200 W). I can use either the HK or the outboard audiosource for this application. Keep in mind the HK amps will still be driving at least the rear 2 channels and possibly the front L and R.
I can wire the two identical speakers in a number of ways. I could:
A. Run them in parallel either w/ one channel (better idea) of the audiosource or in bridged mode (probably not a good idea). I could also use the center channel of the HK for this. Of course, this means the HK would see a four ohm speaker on the center channel, which may or may not be a problem.
B. Run a splitter before the audiosource and then simply run each speaker from the standard outputs.
C. Bridge the audiosource amp (or not) and run the two speakers in series. This way I would have 16 ohms, and the amp, being bridged, would see half of that (8). This seems like the best option--however, I read this online:
Question: am I likely to even notice this back EMF distortion? My main goal is a seamless front soundstage.
Please help--any input would be greatly appreciated.
Re: another question
That is what i would do
You could as easily say parallel in that statement -- it is an argument to only use a single driver (and somewhat valid). The damping factor should be 4 times better wired in series vrs paralel so the amp should be able to have better control the speaker. It will also be less stressed. I'm not sure how the impedance affects the back EMF.
dave
before the audiosource and then simply run each speaker from the standard outputs.[/QUOTE]Andy_A said:
That is what i would do
You could as easily say parallel in that statement -- it is an argument to only use a single driver (and somewhat valid). The damping factor should be 4 times better wired in series vrs paralel so the amp should be able to have better control the speaker. It will also be less stressed. I'm not sure how the impedance affects the back EMF.
dave
thanks for your input. I'm not quite sure I understand what you said in the second part of the post regarding series and distortion.
So you would run a splitter, then? This sounds like it would be a good option, too. Question: Do you think I'd get the same level of performance just running one of the speakers instead of two?
Thanks
So you would run a splitter, then? This sounds like it would be a good option, too. Question: Do you think I'd get the same level of performance just running one of the speakers instead of two?
Thanks
!!?! I have to put in my 2 cents - 2 drivers series or parallel will have the SAME efficiency (that is ratio of electric power in to acoustic power out) - sensitivity as usually thought of will be greater with the series connection - but less if you happen to have a 'current source' amp as opposed to the 'normal voltage source' amp.
Efficiency does not depend on the number of drivers - if you have 4 drivers then for a given acoustical power output each driver only has to produce a quarter of the power that one driver would but the total power input is the same. Probably distortion from suspension nonlinearities and doppler distortion will be reduced with more drivers
A series resistor will waste power (reduce efficiency and sensitivity) and change the damping (this maybe good or bad depending on the rest of the design) and change the design of the cross over - not good or bad but different.
I'd tend to vote for series, safe for the amp and I hate to waste power - so much easier to create 'good' low power. But it is but one of many design decisions and I bet the amp won't mind to much unless you play things very loud - just the amp designers doing a little CYA, of course maybe the amp really is not happy with 4 ohm loads ...
Bill
Efficiency does not depend on the number of drivers - if you have 4 drivers then for a given acoustical power output each driver only has to produce a quarter of the power that one driver would but the total power input is the same. Probably distortion from suspension nonlinearities and doppler distortion will be reduced with more drivers
A series resistor will waste power (reduce efficiency and sensitivity) and change the damping (this maybe good or bad depending on the rest of the design) and change the design of the cross over - not good or bad but different.
I'd tend to vote for series, safe for the amp and I hate to waste power - so much easier to create 'good' low power. But it is but one of many design decisions and I bet the amp won't mind to much unless you play things very loud - just the amp designers doing a little CYA, of course maybe the amp really is not happy with 4 ohm loads ...
Bill
series or parallel huh, hmmm. I would actually never use series with woofers because they are used in their resonance frequency region. And as we all know the impedance rises at the Fs, so when you would wire e.g. two woofers in series these two woofers have to be EXACTLY the same. A tiny difference in the mass or suspension will change the Fs AND then will change the impedance (drastically at the Fs!). So, power distribution between two series wired woofer will possibly NEVER be equal if the drivers aren't 100% the same. Also, the bassresponse won't be very acccurate that way. Both units won't act as one.
thats my five cents.
thats my five cents.
parallel or series speaker connections
There are many amps with four pairs of binding posts. I always thought that meant the amp was designed to power two pairs of stereo speakers, usually in different rooms, at the same time. When playing two pairs of stereo speakers I thought they were in parallel. Does anyone one know if they are in parallel or series?
Some amps even have a speaker selection switch on the front. The switches, I've seen, have three positions: speakers, A, B, or A+B. Again i would like to know if they are in parallel or series. Is there a standard for this type of setup?
I also have a Nakamichi speaker selection switch with leads for connecting to a right and left channel set of amp binding posts. It has connectors for two pairs of stereo speakers, with the typical option A, B, or A+B.
My real question is: I have a pair of stereo speaker in two different rooms and would like to know what method is best, parallel or series. Both pairs are 8ohm.
Thanks,
henry
There are many amps with four pairs of binding posts. I always thought that meant the amp was designed to power two pairs of stereo speakers, usually in different rooms, at the same time. When playing two pairs of stereo speakers I thought they were in parallel. Does anyone one know if they are in parallel or series?
Some amps even have a speaker selection switch on the front. The switches, I've seen, have three positions: speakers, A, B, or A+B. Again i would like to know if they are in parallel or series. Is there a standard for this type of setup?
I also have a Nakamichi speaker selection switch with leads for connecting to a right and left channel set of amp binding posts. It has connectors for two pairs of stereo speakers, with the typical option A, B, or A+B.
My real question is: I have a pair of stereo speaker in two different rooms and would like to know what method is best, parallel or series. Both pairs are 8ohm.
Thanks,
henry
henry - I think the labeling the rear panel might give a hint - i.e. minimum 8ohms per pair, etc. If two pairs only, likely to be in parallel - where the combinations could get interesting is if three pairs
Which method is "best" very much depends on the system's variables, and don't forget there's only one volume control for all speaker outputs on most amps, so unless you add additional controls to secondary room(s), you won't have independent level controls. If thinking of adding controls to those rooms, the tapped transformer types are probably safest load on the amp.
Which method is "best" very much depends on the system's variables, and don't forget there's only one volume control for all speaker outputs on most amps, so unless you add additional controls to secondary room(s), you won't have independent level controls. If thinking of adding controls to those rooms, the tapped transformer types are probably safest load on the amp.
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Thanks for the reply. I also have been considering a remote volume control in one room. It would be between the amp and second pair of speakers. I was thinking of running a pair of cables to a volume control in a 1st floor room. Cables would then go a short distance to the speakers.
I'm only familiar with L pads and autoformers. Are tapped transformers a better alternative? Do tapped transfomers also have an off position? Are they expensive? I would like to minimize number of switches so an off position would eliminate the need for a toggle switch.
I'm only familiar with L pads and autoformers. Are tapped transformers a better alternative? Do tapped transfomers also have an off position? Are they expensive? I would like to minimize number of switches so an off position would eliminate the need for a toggle switch.
A+B amp output is strictly parallel connection. Do not connect two different loudspeakers in series!
L-pad is out of question. Tapped (auto)transformer is the only correct solution. Price depends on the maximum transformer wattage. Off position is easy to make with multi-position selector switch.
L-pad is out of question. Tapped (auto)transformer is the only correct solution. Price depends on the maximum transformer wattage. Off position is easy to make with multi-position selector switch.
Thanks for the clarification. So an autoformer is the same thing as a tapped transformer. I have a top of the line Niles autoformer that is like new. Would that be a good choice? I found a few other brands in the $300+ range and don't want to spend that much.
I also don't have a problem with building one. Does anyone know of a parts list and schematic?
I also don't have a problem with building one. Does anyone know of a parts list and schematic?
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something like this is what I had in mind for a simple control
Atlas Sound AT100D 100W Auto Transformer Speaker Volume Control Decora Style
as they're low voltage, they shouldn't require anything other than a simple plastic mounting bracket
Arlington Industries LVMB1 Single Gang Low Voltage Mounting Bracket New Construction
and of course, don't forget that will only turn the levels down, so if you want truly independent volume controls throughout the installation, a somewhat more elaborate amp and control configuration would be required.
Atlas Sound AT100D 100W Auto Transformer Speaker Volume Control Decora Style
as they're low voltage, they shouldn't require anything other than a simple plastic mounting bracket
Arlington Industries LVMB1 Single Gang Low Voltage Mounting Bracket New Construction
and of course, don't forget that will only turn the levels down, so if you want truly independent volume controls throughout the installation, a somewhat more elaborate amp and control configuration would be required.
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