More Volume

[TLS Guy]

Speakers are a complex load. Two different sets of speakers in parallel on the same amp are no more complex impedance than one speaker, although they are lower impedance, which may or may not be too low impedance for the amplifier at some frequencies and draw too much current. The impedances of two speakers in parallel do not effect each other if the amplifier is not overloaded by low impedance. The impedance curve of two speakers in parallel is not any more complex than one speaker. Impedance curves are measured with simple sine waves. Music is not a simple sine wave, so the impedance curve is a simplification.

However, if two different speakers are wired in series, the amplifier voltage is divided between the complex impedances of the two speakers, so the impedance curve of each speaker influences the frequency response of the other speaker. The higher impedance of speakers in series is less dangerous to the amplifier than the impedance of one speaker.

300W is 24.8dBW. If the speaker sensitivity is 101dB SPL at 1W at 1m, this amp with this speaker would be 126dB SPL at 300W at 1m. NIOSH Recommended Exposure Limit for 126dB SPL is 2 seconds in 24 hours. THX standard level is 85dB SPL at -20dBFS at the listening position. This amp with this speaker would be 105dB SPL at 300W at 11.7m or 38.5ft. NIOSH REL for 105dB SPL is 4 minutes 43 seconds in 24 hours. I value my hearing.

The volume control sets the voltage gain of the pre-amplifier that drives the main amplifier. The output voltage of the pre-amplifier depends on the source device output voltage and the voltage gain. The main amplifier output voltage depends on the voltage input to the amplifier and the voltage gain of the amplifier. The main amplifier output voltage and the speaker load impedance determine the output power. With music, full power of the system is probably reached well before the volume control is fully clockwise. With music, an arbitrary "three o'clock" position of the volume control would very likely overdrive the main amplifier to produce clipping, especially if it is driving low impedance with high current.

You can believe what you want, but what you say is erroneous. You are forgetting that resistance is scalar, but impedance is a vector, having both magnitude and direction. So your theory is a gross oversimplification of the situation.

 

[PENG]

Thanks for all the information. Decided to send my amp to Bryston for the "back to the future program".

Which preamp are you using? I am wondering if it has high enough voltage for the Bryston 4B. I am very familiar with the 4B, it should be able to blow the Cerwin Vega D3, and has enough juice for the D9.

 

[Audiophile Heretic]

You can believe what you want, but what you say is erroneous. You are forgetting that resistance is scalar, but impedance is a vector, having both magnitude and direction. So your theory is a gross oversimplification of the situation.

1/Z = 1/Z1 + 1/Z2

For one sine wave frequency:

vector impedance Z = (R + jX) = |Z|(cos Θ + j sin Θ) = |Z| e^jΘ

scalar impedance magnitude |Z| = √(R² + X²)

phase angle Θ = arctan(X/R)

reactance X = (2πfL - 1/2πfC)

Speaker impedance can't be modeled by a simple mathematical function.

Speaker impedance X = 0, Z = R, Θ = 0 when the slope of the impedance magnitude on the graph is 0, such as at minimum or maximum impedance.

Music is not one sine wave.

It's not my theory. Tell me where I'm wrong or what I'm forgetting.

 

[PENG]

You can believe what you want, but what you say is erroneous. You are forgetting that resistance is scalar, but impedance is a vector, having both magnitude and direction. So your theory is a gross oversimplification of the situation.

What he said about the speakers connecting in parallel is not erroneous though, just that he really doesn't know, none of us know, whether the parallel impedance is more complex or not, but that really doesn't matter. What matter is whether the two speakers would end up with impedance dips coincide enough at enough points that overload the amp.

For example, and just for argument sake, if both speakers have dips to below 4 ohms over the range 50-150 Hz, then it would result in combined impedance dips of 2 ohms being presented to the amp.

If the combined load does not dip below 4 ohms, or would dip to 2 ohms but only scattered (over the freq range) here and there in very narrow dips, say less than 0.5 octave, then it won't hurt the Bryston amp. Regardless, as you said

"You never use two different speakers connected to the same amp. "

My point is simply that Audiophile Heretic is not "erroneous" in saying

"which may or may not be too low impedance for the amplifier at some frequencies and draw too much current. "

Without knowing what the OP is using to drive the power amp, it is possible that the clipping is caused by the preamp.

 

[PENG]

1/Z = 1/Z1 + 1/Z2

For one sine wave frequency:

vector impedance Z = (R + jX) = |Z|(cos Θ + j sin Θ)

scalar impedance magnitude |Z| = √(R² + X²)

phase angle Θ = arctan(X/R)

Speaker impedance can't be modeled by a simple mathematical function.

Speaker impedance X = 0, Z = R, Θ = 0 when the slope of the impedance magnitude on the graph is 0, such as minimum and maximum impedance.

Tell me where I am wrong.

If you guys are going to get technical enough, please use the term "Phasor", instead of "vector", lol..

 

[Audiophile Heretic]

If you guys are going to get technical enough, please use the term "Phasor", instead of "vector", lol..

I had learned "vector" in school years ago, so I had to look it up. According to what I found: the term "phasor" is a portmanteau of "phase vector", so either term is technically correct. Phasors are vectors. "Vector" is the general term for numbers with magnitude and direction. "Phasor" is the specific term electrical engineers use for numbers with magnitude and phase. Thanks!

 

[Audiophile Heretic]

What he said about the speakers connecting in parallel is not erroneous though, just that he really doesn't know, none of us know, whether the parallel impedance is more complex or not, but that really doesn't matter. What matter is whether the two speakers would end up with impedance dips coincide enough at enough points that overload the amp.

For example, and just for argument sake, if both speakers have dips to below 4 ohms over the range 50-150 Hz, then it would result in combined impedance dips of 2 ohms being presented to the amp.

If the combined load does not dip below 4 ohms, or would dip to 2 ohms but only scattered (over the freq range) here and there in very narrow dips, say less than 0.5 octave, then it won't hurt the Bryston amp. Regardless, as you said My point is simply that Audiophile Heretic is not "erroneous" in saying

Without knowing what the OP is using to drive the power amp, it is possible that the clipping is caused by the preamp.

The clipping in the power amplifier output voltage may be caused by application of too much voltage at the power amplifier input and too much current drawn from the power amplifier output by too low speaker impedance. Yes, speakers have complex impedance. Speaker impedance is not "more" complex when two different speakers are in parallel. Different speakers might have impedance dips at different frequencies, which might be easier to drive than two of the same speakers in parallel with impedance dips at the same frequency.

Yes, I would drive only one speaker or the other with the amplifier, not both. I probably wouldn't turn the volume control past 12 o'clock center. I would defeat any tone controls or other equalization.

 

[PENG]

I had learned "vector" in school years ago, so I had to look it up. According to what I found: the term "phasor" is a portmanteau of "phase vector", so either term is technically correct. Phasors are vectors. "Vector" is the general term for numbers with magnitude and direction. "Phasor" is the specific term electrical engineers use for numbers with magnitude and phase. Thanks!

Of course, vector is not wrong at all. Phasor, phasor diagrams are just more specific to EE. It is more appropriate in the EE world, but I have no objection to your use of vector in this just, sort of teasing only..

 

[PENG]

The clipping in the power amplifier output voltage may be caused by application of too much voltage at the power amplifier input and too much current drawn from the power amplifier output by too low speaker impedance. Yes, speakers have complex impedance. Speaker impedance is not "more" complex when two different speakers are in parallel. Different speakers might have impedance dips at different frequencies, which might be easier to drive than two of the same speakers in parallel with impedance dips at the same frequency.

Yes, I would drive only one speaker or the other with the amplifier, not both. I probably wouldn't turn the volume control past 12 o'clock center. I would defeat any tone controls or other equalization.

Agreed with you the first time, the only minor point I made was the "more complex" part because that would depend on how you define "more". In either case, if there is the j term in the equation z = R+jwL-j/wC (w is Omega), then it is a complex number, so what do we consider more complex, would it be more complex if the j part becomes more prominent? That would depend on which speakers are being connected in parallel, but by such a definition, it is possible for the combined impedance to become more, or less complex.

All these, are just for argument sake, or fun, so feel free to ignore.

 

[Audiophile Heretic]

Agreed with you the first time, the only minor point I made was the "more complex" part because that would depend on how you define "more". In either case, if there is the j term in the equation z = R+jwL-j/wC (w is Omega), then it is a complex number, so what do we consider more complex, would it be more complex if the j part becomes more prominent? That would depend on which speakers are being connected in parallel, but by such a definition, it is possible for the combined impedance to become more, or less complex.

All these, are just for argument sake, or fun, so feel free to ignore.

If the reactance X = (wL - 1/wC) is more prominent (X > R), then the impedance phasor Z is more reactive, not more complex. Two parallel phasors are not necessarily more reactive than either phasor. I used "phasor". I can be taught!

Complex numbers are vectors as opposed to scalars. Numbers are either complex or they are not. There is no scale of complexity. I suppose three-dimensional vectors are "more" complex than two-dimensional vectors, but phasors in electrical engineering are two-dimensional.

It is annoying that there is no alt code for lower case omega. Sometimes I use 2πf.

I agree with you. This intellectual discourse is just for fun. There are too many trolls on audio forums and social media in general.

 

[Audiophile Heretic]

I just recently purchased a 4B Bryston amp, 2 cerwin vega D9 and 2 cerwin vega D3 ( D3 where added to help prevent clipping)

I know everyone states this should be loud enough but it's not, I like it loud. If i give it more volume than 3 o'clock it clips. I'm thinking of purchasing a second 4B and somehow running 1 amp for each side of speakers. Not really sure how it's done.

Any guidance would be greatly appreciated.

How would adding speakers prevent clipping? Higher current drawn by lower impedance of speakers in parallel might induce clipping at a lower output voltage, which would be a lower setting on the volume control.

You could run the two amps in parallel (two Y cords) and connect one set of speakers to each amp. You stand to gain at most 3dB, which is an increase in volume, but not double the volume. Double the volume would be about 10dB or ten times the power. Ten times 300W is 3kW or ten 300W amplifiers and ten pairs of speakers. You would make your ears bleed.

 

[Audiophile Heretic]

I just recently purchased a 4B Bryston amp, 2 cerwin vega D9 and 2 cerwin vega D3 ( D3 where added to help prevent clipping)

I know everyone states this should be loud enough but it's not, I like it loud. If i give it more volume than 3 o'clock it clips. I'm thinking of purchasing a second 4B and somehow running 1 amp for each side of speakers. Not really sure how it's done.

Any guidance would be greatly appreciated.

Maybe you have blown caps in the speaker crossovers, or blown high frequency speakers.

 

[croseiv]

If you want ear bleeding loudness, may I suggest this:


JBL SRX910LA 8 Powered Line Array 4 Powered Subwoofer Ground PA System

47,000 US dollars will get it in your room.

Yes, a bit of tongue-in-cheek here.