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Ohms ? What are they

lini said:
More like +6 dB ideally (+ 3 dB due to twice the input power and another +3 dB due to twice the diaphragm area), reasonable coherence due to close proximity of the two sound sources and sufficient wave length provided. In case of stacked speakers that should work out pretty well at least in the bass range.

Greetings from Munich!

Manfred / lini
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I disagree. But no reason to debate it in this thread. We agree that increased output is noticeable.
 
ric27 said:
reading the manual for my Sansui 5000x it states 65 watts into 8 ohms - 85 watts into 4 ohms.

I have 4 Advents stacked (2 right 2 left ) and wired up to act as one very large 4 ohm speaker per channel . the set up sounds very good to me and the 5000x drives them with ease.

Am it gaining , loosing or breaking even on power with this set up vs the standard 8 ohm load?

Is 4 ohms a higher load than 8 ohms?

What does this all mean?

Ric
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The way you have your speakers hooked up is presenting a 4 ohm load(per channel) to your amp. So since the amp is rated at 85wpc into 4 ohms that means each speaker can receive up to 42.5 watts of power.
 
Unless the amplifier can produce double output power when the impedance is halved, the +3 dB advantage of two pair of speakers would be mostly offset by the fact that the output would be shared between both pairs so you'd be back where you started.

However multiple speakers do offer a number of significant advantages:

Decreased loudspeaker distortion (at a given SPL).
Increased power handling.
Improved response - especially LF

However some would argue some penalty to soundstaging/imaging but this can be minimized by stacking so that the HF drivers are closest; ie placing the upper speaker upside down. Personally I have found the advantages of multiple speakers can outweigh the disadvantages but it depends on a number of factors. Generally works best when the speakers are identical and stacked as described.
 
ric27 said:
Yes they are quite Impressive. I have been a Advent fan for 50 yrs but just recently have had two sets to stack in parallel .

What I have been trying to get at through this thread is, am I getting more out of my amp. using the stacked in parallel vs connecting two sets of speakers to amp output and running a+b?
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Make sure the upper speaker in inverted (upside down)...;)

I have two pair of Advents, but haven't run them together in a few years. But I did at one time.
 
What nobody has specifically mentioned is that the difference between 65W and 85W is trivial, probably on the order of about 1dB. Barely noticeable. If you want to continue to run your Advents stacked, you basically have two choices: series or parallel. Parallel has already been discussed. If you run them in series you will see (although not necessarily hear) a decrease in maximum output power, but it will be an easier load on your amp.
 
swechsler said:
What nobody has specifically mentioned is that the difference between 65W and 85W is trivial, probably on the order of about 1dB. Barely noticeable. If you want to continue to run your Advents stacked, you basically have two choices: series or parallel. Parallel has already been discussed. If you run them in series you will see (although not necessarily hear) a decrease in maximum output power, but it will be an easier load on your amp.
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True, but why is it pertinent?
 
As I have stated I am running volume on the amp between 2 & 3, so nowhere near max power.

Spark1 mention earlier that heading towards max power the ability of the amp to double the output with reduced ohm load diminishes. So can I assume that at lower power output I am achieving closer to the 3db advantage?

I do by the way have the Advents stacked the proper way with the top speaker bottom up.

Again thanks to every one for the input to my thread.
Ric
 
spark1 said:
True, but why is it pertinent?
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As was mentioned earlier, the true impedance of the Advents is closer to 6Ω than 8Ω, so connecting them in parallel will result in a nominal 3Ω load, something that a vintage receiver like the OP's Sansui may not be happy with, which could result in output device failure.
 
ric27 said:
Spark1 mention earlier that heading towards max power the ability of the amp to double the output with reduced ohm load diminishes. So can I assume that at lower power output I am achieving closer to the 3db advantage?
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No because you are ultimately limited by the maximum output the amplifier is capable of. In this case the additional pair allows you to extract 1 additional dB at full output. At lower levels it is not relevant - just as it would not be relevant if your car's fuel tank was completely full or only 1/8 full for the purpose of driving around the block.

Again this assumes identical 8 ohm speakers are used.
 
[QUOTE="62caddy, post: . . At lower levels it is not relevant -

.[/QUOTE]
Just for clarification, you are saying is that the demands of the power supply are the same at all volume settings?
 
Read up on Ohm's Law.

Think of the volume control as controlling voltage. Turn the knob up, more voltage, Turn the knob down, less voltage. So clearly the demand on the power supply changes with volume.

Current is directly proportional to voltage (assuming fixed resistance).

I think you are confusing several topics:

1. The maximum output capability of the amp
2. The effect of power on loudness
3. The effect of two speakers vs one on loudness
 
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swechsler said:
As was mentioned earlier, the true impedance of the Advents is closer to 6Ω than 8Ω, so connecting them in parallel will result in a nominal 3Ω load, something that a vintage receiver like the OP's Sansui may not be happy with, which could result in output device failure.
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Are the Advents rated 8 ohm or 6 ohm nominal impedance?
 
ric27 said:
[QUOTE="62caddy, post: . . At lower levels it is not relevant -


Just for clarification, you are saying is that the demands of the power supply are the same at all volume settings?
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Two speakers will draw twice the current (thus wattage) than a single pair but only up to the maximum power the amplifier is capable of -which in this case is 65 or 85 wpc. Below the maximum it is what it is.
 
spark1 said:
Read up on Ohm's Law.

Think of the volume control as controlling voltage. Turn the knob up, more voltage, Turn the knob down, less voltage. So clearly the demand on the power supply changes with volume.

Current is directly proportional to voltage (assuming fixed resistance).

I think you are confusing several topics:

1. The maximum output capability of the amp
2. The effect of power on loudness
3. The effect of two speakers vs one on loudness
Click to expand...

No doubt I am confused and confusing.

I think what I am wanting to know is the performance of the speakers in terms of SPL and how that relates to 4 ohm and 8 ohm set up I have described at the volume levels I am listening at.
I think you answered my question when you posted " As you move closer to maximum output, the amp is less and less able to do so. At max output, power is only 40% higher into the doubled load (which is actually pretty good performance, relative to many other receivers)"

So my thought was that at lower volumes the amp could be producing the gains nearer the 3db, more so than at what could be expected higher volume levels. But then that was poo pooed in a post later by another member which did confuse me.
Ric
 
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