Seemed obvious to me that was what Joe was getting at. Question remains as to what that has to do with SQ in the audio band, if anything. Waiting to see what develops from here.
I am not and have not said that 1MHz or 4MHz bandwidth is needed. All I said was that the circuit was capable of that. But to me, the settling time is even more important than bandwidth (instinctively I associate that with better linearity). Certainly, it is clear, the phono is flat to 100KHz and maybe that is all that is needed. Some would say less is needed. Personally, I think there are bigger things to fry than flat beyond 20KHz.
Let’s see:
- “settling time” is defined and makes sense only for second order, or perhaps higher, systems with underdamped response. Not the case here.
- so I assume you mean “rise time”. In this case, I have some news for you: bandwidth and rise time are exactly inverse proportional, with a constant of 0.35. So you are once again showing your ignorance in the very basics.
- as of any relationship between rise time/bandwidth and linearity, here’s some more news for you: there is absolutely no relationship. So your instincts are once again flat wrong.
My little trap and you fell into it 'instinctively.'
Classic strawman, I did NOT say that there was a relationship between bandwidth and linearity. Maybe settling time. The circuit I use has a rated settling time and I associate with SQ. So it must be doing something right.
Such arrogance! Do you feel taller in your boots now? I should pity you that you felt a need to say that.
BTW, do you agree with Hans, or is he too lacking basic understanding when he got anti (sic) RIAA so wrong. Why did you not pull him up on that one? Or have you just got your cross-hairs set on me? I have many Canadian friends, I am glad you are not one of them. And sad too. Sooooooo sad.
PPS: Say something intelligent about RIAA and Inverse RIAA, just so that I know you are not ignorant too. Then we shall make ourselves, you and me, a little crowd of ignorant people. Hey! The more the merrier!
Classic strawman, I did NOT say that there was a relationship between bandwidth and linearity. Maybe settling time. The circuit I use has a rated settling time and I associate with SQ. So it must be doing something right.
Such arrogance! Do you feel taller in your boots now? I should pity you that you felt a need to say that.
BTW, do you agree with Hans, or is he too lacking basic understanding when he got anti (sic) RIAA so wrong. Why did you not pull him up on that one? Or have you just got your cross-hairs set on me? I have many Canadian friends, I am glad you are not one of them. And sad too. Sooooooo sad.
PPS: Say something intelligent about RIAA and Inverse RIAA, just so that I know you are not ignorant too. Then we shall make ourselves, you and me, a little crowd of ignorant people. Hey! The more the merrier!
Last edited:
"Even Einstein himself claimed ignorance when he said, “Imagination is more important than knowledge.”"
https://living-universe.com/wp-content/uploads/2018/12/Einstein-Fool-paper.pdf
Ignorance is not always bad.
We all come from the same cradle!
https://living-universe.com/wp-content/uploads/2018/12/Einstein-Fool-paper.pdf
Ignorance is not always bad.
We all come from the same cradle!
Last edited:
Go ahead and read again what you wrote.
Wait, don’t bother, I don’t expect you to admit any wrong doing or lack of basic knowledge, you are able and willing to debate even the sex of angels if it comes to that. You are one of those very few with apparently infinite reserves of time.
You got this one right. Ignorance is not necessary bad and is definitely not a sin. Refusing to admit it is. To be proud of your ignorance is even worse.
Many systems can be second order or higher if FR extends high enough that parasitic reactances have to be taken into account in the model.
Anyway, Joe is probably not the only guy who looks for square wave ringing and associates too much ringing with SQ problems. How could that be? If true, maybe its by way of some roundabout mechanism. RF noise peaking, demodulation in junctions, blah, blah, blah. Anyone want to try to measure that one and 'prove' it can have audible effects? I didn't think so.
Anyway, Joe is probably not the only guy who looks for square wave ringing and associates too much ringing with SQ problems. How could that be? If true, maybe its by way of some roundabout mechanism. RF noise peaking, demodulation in junctions, blah, blah, blah. Anyone want to try to measure that one and 'prove' it can have audible effects? I didn't think so.
Did I see you hand up there for a brief moment? Cant you dive into that and show the results? I mean straighten out the questions marks you have?
//
//
Is that your / Allen's fully balanced pre amp Joe?
Oh BTW, a belated happy birthday I wish you all the very best.
cheers
Terry
Please, this is not about trolling, but a real question.
I think I know the answer, but would others come to the same conclusion that I have? In which case it is a remarkable conclusion.
This has to do with cone excursion and that Purifi has set great store on this as a source of distortion.
The surround issue in one, that a cone in the negative (-) position means the cone area, Sd, can become significantly increased and in the positive (+) the Sd shrinks, and this is a source of distortion. The other one is that excursions suffer from what they call Force Factor Modulations, or FFM.
The cause of FFM can be detected in drivers in a simple way:
Take a driver and connect this to an LCR set to 1Khz. You will hear the sine, of course, but there is little excursion, take note of the inductance. Now move the cone in (-) and keep it steady, by say 4mm. The inductance goes up and by implication so does BL force factor. Now gently put fingers behind the cone and move it forward (+) and you will note that this causes a reduction inductance, hence the same in BL force factor. Hence this is the cause of FFM. Purifi has created samples of AM distortion caused by FFM and compared to FM distortion (Doppler) and you can hear clearly that the FFM/AM distortion is worse.
Conclusion: Speaker systems with lower excursion have an advantage, at least on paper, but also in reality. Purifi's 6.5" drivers try to fix these problems in a commonly used size and not to go for a large Sd. cone drivers.
Now we come to our puzzle/question:
Take a 6.5" driver of decent quality, 8 Ohm. Put it in a sealed box and with an alignment that is flat from 30 Hertz and upwards (yes, this is a thought experiment but leading to a real outcome).
Feed 2.83V RMS @ 40 Hertz into it and measure the db-SPL at 1 metre. Let us say we measure a healthy 90dB. Let us make this our target sound pressure level, SPL.
Let us also stipulate that the 30 Hertz create a peak-to-peak excursion of 8mm (-/+4mm) and well within the rated Xmax, which usually for this size driver can be Xmax 6mm.
So we have significant but linear excursion and all should be well. But of course the driver is not perfect. In that case, if we can get some way to reduce excursion, that would be a good idea. Even if some complexity is added.
Now let us take four drivers and wire them in series-parallel and hence still nominally 8 Ohm. We now use the same 2.83V RMS and 30 Hertz, and now we find that we are getting 96dB at 1 metre. The power from the amplifier is still the same, a nominal (not in reality, but let us put that aside for now) 1 Watt.
This is where it gets interesting. Our target value was 90 dB-SPL and hence we can reduce our voltage to 1.414 Volt RMS and our microphone records 90dB-SPL. The amplifier is now only producing a 1/4 of the power and hence nominally 250mW - yes, a quarter of a Watt.
Since that 250mW is divided up into four drivers and they only see 62.5mW each.
Here is the question, we had 8mm peak-to-peak excursion with one driver, what would be the peak-to-peak excursion be now if we were to look at any of our four drivers?
What would your answer be?
What is clear is that the reduction is quite dramatic, lower distortion due to surround rolling, lower BL modulated AM distion (FFM). Also, this is where line sources come in and why line sources must be lowering distortion with conventional drivers. Then there is the matter of headroom and so on.
Keen to hear what you guys have to say?
Cheers, Joe
PS: The problem with FFM is that low frequencies (excursion) mixed with mid-frequencies (IMD), cause AM distortion. If you are as interested as I am, then please digest the Purifi blogs that deal with it.
PPS: I am sure that Purifi does not reveal every nuts and bolt, but they do reveal a lot. One thing they are quiet about is how they have achieved a remarkable off-axis response better than any other 6.5" driver I have seen out there, and I have seen a LOT of them. The solution is very novel and you can see it in their pictures.
I think I know the answer, but would others come to the same conclusion that I have? In which case it is a remarkable conclusion.
This has to do with cone excursion and that Purifi has set great store on this as a source of distortion.
The surround issue in one, that a cone in the negative (-) position means the cone area, Sd, can become significantly increased and in the positive (+) the Sd shrinks, and this is a source of distortion. The other one is that excursions suffer from what they call Force Factor Modulations, or FFM.
The cause of FFM can be detected in drivers in a simple way:
Take a driver and connect this to an LCR set to 1Khz. You will hear the sine, of course, but there is little excursion, take note of the inductance. Now move the cone in (-) and keep it steady, by say 4mm. The inductance goes up and by implication so does BL force factor. Now gently put fingers behind the cone and move it forward (+) and you will note that this causes a reduction inductance, hence the same in BL force factor. Hence this is the cause of FFM. Purifi has created samples of AM distortion caused by FFM and compared to FM distortion (Doppler) and you can hear clearly that the FFM/AM distortion is worse.
Conclusion: Speaker systems with lower excursion have an advantage, at least on paper, but also in reality. Purifi's 6.5" drivers try to fix these problems in a commonly used size and not to go for a large Sd. cone drivers.
Now we come to our puzzle/question:
Take a 6.5" driver of decent quality, 8 Ohm. Put it in a sealed box and with an alignment that is flat from 30 Hertz and upwards (yes, this is a thought experiment but leading to a real outcome).
Feed 2.83V RMS @ 40 Hertz into it and measure the db-SPL at 1 metre. Let us say we measure a healthy 90dB. Let us make this our target sound pressure level, SPL.
Let us also stipulate that the 30 Hertz create a peak-to-peak excursion of 8mm (-/+4mm) and well within the rated Xmax, which usually for this size driver can be Xmax 6mm.
So we have significant but linear excursion and all should be well. But of course the driver is not perfect. In that case, if we can get some way to reduce excursion, that would be a good idea. Even if some complexity is added.
Now let us take four drivers and wire them in series-parallel and hence still nominally 8 Ohm. We now use the same 2.83V RMS and 30 Hertz, and now we find that we are getting 96dB at 1 metre. The power from the amplifier is still the same, a nominal (not in reality, but let us put that aside for now) 1 Watt.
This is where it gets interesting. Our target value was 90 dB-SPL and hence we can reduce our voltage to 1.414 Volt RMS and our microphone records 90dB-SPL. The amplifier is now only producing a 1/4 of the power and hence nominally 250mW - yes, a quarter of a Watt.
Since that 250mW is divided up into four drivers and they only see 62.5mW each.
Here is the question, we had 8mm peak-to-peak excursion with one driver, what would be the peak-to-peak excursion be now if we were to look at any of our four drivers?
What would your answer be?
What is clear is that the reduction is quite dramatic, lower distortion due to surround rolling, lower BL modulated AM distion (FFM). Also, this is where line sources come in and why line sources must be lowering distortion with conventional drivers. Then there is the matter of headroom and so on.
Keen to hear what you guys have to say?
Cheers, Joe
PS: The problem with FFM is that low frequencies (excursion) mixed with mid-frequencies (IMD), cause AM distortion. If you are as interested as I am, then please digest the Purifi blogs that deal with it.
PPS: I am sure that Purifi does not reveal every nuts and bolt, but they do reveal a lot. One thing they are quiet about is how they have achieved a remarkable off-axis response better than any other 6.5" driver I have seen out there, and I have seen a LOT of them. The solution is very novel and you can see it in their pictures.
Last edited:
"Not happy, Jan."
That joke will go over the heads of some here. In my mind I am nowhere that old. 🙂
Take a look at my most recent post #8014. Remember that time when you brought a pair of ribbon tweeters and we connected them up and measured +6dB more output and that it was only a doubling of power and not quadrupling, remember that? This is along the same line, but at LF.
No, it is not the RTP preamp. Give me a call and I will tell you which one it is.
BTW, I think I have a pair of your sunglasses here, I think they were left behind last time.
Cheers, Joe
Edit: I have mixed 30 Hertz and 40 Hertz, when you read it, they should all be 40 Hertz except where it says "flat from 30 Hertz and upwards."
Sorry for the mixup.
Sorry for the mixup.
Last edited:
This has been hashed through a number of times already. Maybe you missed it?
Keeping it brief: There would be two main problems, (1) measure something, expecting it would most likely produce a small, non-impressive number, and then (2) produce compelling, publication quality research showing it is audible to humans.
Maybe add, (3) make a strong case it is a big enough problem to justify the many costs of not ignoring it.
IMHO the cost and complexity of doing anything past step (1) would be impractical for any one individual to take on (well, maybe except for Musk, Bezos, etc.).
Without doing anything past step (1) nobody will care and or maybe it will be criticized as bunk (just watch and see the response to this). That being the case, I have better things to do.
PM if anyone wants a long version.
Sorry for the interruption.
I was about to ask 'why' then remembered that Spectral did a lot of stuff because they could 😀
...terrifying.
If the sensitivity is 90dB/W for 1 speaker element then series-paralleling 4 speakers, like..
doesn't suddenly change the sensitivity from 90 to 96 dB/W, start over again Joe. 😉
U-T
Loudspeakers are transducers, not resistors. Their impedance has two parts, the actual electrical resistance and the energy that transfers from electrical to mechanical. (sound!)
When you have multiple loudspeakers at some frequency they couple. At that point the mechanical part of resistance drops. So there is greater output. Also a greater load on the amplifier.
The second issue is that your effective piston area increases, thus making the loudspeaker system more directional.
However a loudspeaker that is rated at 90 dB at 2.83 volts at 1 M is not very efficient, meaning the electrical resistance is a significant part of the total resistance, thus you will not get the full theoretical 6 dB boost. It will more likely be around 4.5 dB.
Loudspeakers are transducers, not resistors. Their impedance has two parts, the actual electrical resistance and the energy that transfers from electrical to mechanical. (sound!)
When you have multiple loudspeakers at some frequency they couple. At that point the mechanical part of resistance drops. So there is greater output. Also a greater load on the amplifier.
The second issue is that your effective piston area increases, thus making the loudspeaker system more directional.
However a loudspeaker that is rated at 90 dB at 2.83 volts at 1 M is not very efficient, meaning the electrical resistance is a significant part of the total resistance, thus you will not get the full theoretical 6 dB boost. It will more likely be around 4.5 dB.