I swear, there has never been a question that is so difficult to ask clearly! Getting my point across seems to be impossible!
Let's go at this another way;
If you had the signal that is going into a driver displayed on an oscilloscope screen, and you had the signal coming out of the driver displayed on an oscilloscope screen, would those two displays be identical? Would they overlay with no deviation? jj
Let's go at this another way;
If you had the signal that is going into a driver displayed on an oscilloscope screen, and you had the signal coming out of the driver displayed on an oscilloscope screen, would those two displays be identical? Would they overlay with no deviation? jj
" .... if you measured a drive signal and compared it, a pressure measurement would not be consistently proportional to it with regard to frequency, as might be interpreted in a typical response plot, with expected phase variation. ...."
OK. Now we're getting somewhere!
Your explanation sounds like one of the many descriptions (or definitions) of DISTORTION. Am I not correct? Any difference in the displayed signal on the second screen would qualify as distortion, would it not?
I think it might, anyway.
So here's the big question, gentlemen: wouldn't the second driver in a series distort the already-distorted signal even more? And at some point (I can't quantify exactly where) won't that distortion be audible? And by that I mean, won't audible distortion be noticeable FIRST in the second driver in a series pair? I don't care whether we're talking about measuring with sophisticated measuring equipment at lower levels, or whether we're talking about someone in the room noticing a strange sound coming from the speaker under high drive conditions at a party. Won't it ALWAYS be the second driver in a series pair that distorts more?
No matter what the answer is, I'd like to thank you for following me through this incredible mess! jj
OK. Now we're getting somewhere!
Your explanation sounds like one of the many descriptions (or definitions) of DISTORTION. Am I not correct? Any difference in the displayed signal on the second screen would qualify as distortion, would it not?
I think it might, anyway.
So here's the big question, gentlemen: wouldn't the second driver in a series distort the already-distorted signal even more? And at some point (I can't quantify exactly where) won't that distortion be audible? And by that I mean, won't audible distortion be noticeable FIRST in the second driver in a series pair? I don't care whether we're talking about measuring with sophisticated measuring equipment at lower levels, or whether we're talking about someone in the room noticing a strange sound coming from the speaker under high drive conditions at a party. Won't it ALWAYS be the second driver in a series pair that distorts more?
No matter what the answer is, I'd like to thank you for following me through this incredible mess! jj
You're overthinking it.
The short answer is that two reasonably matched drivers (ideally from the same batch), with virtually identical enclosures and room coupling (even one driver being closer to the floor can throw it off a little), will not "couple" any significant artifacts from one driver to another. There's been series. parallel, and series-parallel commercial speaker designs going back decades. The bottom line is that the benefits (like the baffle step correction afforded by a properly sorted "2.5 way") far outweigh the drawbacks in some applications.
In practical terms, if you can reduce a deficiency of a loudspeaker (like an impedance spike,obtrusive baffle step, or nasty midrange resonance of a woofer) by even 10 dB then you've made a very significant improvement. In the speaker world, 20 dB improvement of a deficiency is a whole lot. That's what I mean by you're overthinking it; it's not that examination of these issues is trivial, but that small improvements are often very significant. And I'm speaking from experience.
" .... two reasonably matched drivers (ideally from the same batch), with virtually identical enclosures and room coupling (even one driver being closer to the floor can throw it off a little), will not "couple" any significant artifacts from one driver to another. ... "
Ah .... there's an answer! Thank you, Fast Eddie! Thank you very much. I'll close my eyes and assume you mean electrically as well as acoustically.
no more 
I've got answers on a simple Class-A amp, (on heat management), and on the Hafler arrangment. I think I can experiment on the wall treatment for nearfield. I'm still in the dark about woofer loading, but I think I'll quit now, and not push my luck any more.
You people have been extremely helpful, and very accommodating to an old curmudgeon. Every one of you should give yourself a pat on the back. You deserve it.
Thank you. jj
Ah .... there's an answer! Thank you, Fast Eddie! Thank you very much. I'll close my eyes and assume you mean electrically as well as acoustically.
no more I've got answers on a simple Class-A amp, (on heat management), and on the Hafler arrangment. I think I can experiment on the wall treatment for nearfield. I'm still in the dark about woofer loading, but I think I'll quit now, and not push my luck any more.
You people have been extremely helpful, and very accommodating to an old curmudgeon. Every one of you should give yourself a pat on the back. You deserve it.
Thank you. jj
It's been fun, jimmyjoe!
However, as you leave, I'm left wondering which of the two drivers in a series combination is to be regarded as the SECOND one!
It's been fun, jimmyjoe!
However, as you leave, I'm left wondering which of the two drivers in a series combination is to be regarded as the SECOND one!
The one closest to ground potential.
jjIt's AC. So the first becomes the second every cycle. Which was my point earlier.It's been fun, jimmyjoe!
However, as you leave, I'm left wondering which of the two drivers in a series combination is to be regarded as the SECOND one!
" .... It's AC. So the first becomes the second every cycle.... "
Wrong. It's modulated DC. Is an analogue audio signal DC or AC? - Straight Dope Message Board jj
Wrong. It's modulated DC. Is an analogue audio signal DC or AC? - Straight Dope Message Board jj
Ah .... there's an answer! Thank you, Fast Eddie! Thank you very much. I'll close my eyes and assume you mean electrically as well as acoustically.
Yes, I mean electrically. For all practical purposes, you can go by this assumption.
If you connect two speakers in series, and they are different speakers, then the frequency response of both speakers will be altered.
Remember, some commercial speakers have a series crossover; in other words, the woofer and tweeter are connected in series. It works and it even saves money on the crossover parts. Put a capacitor in parallel with the woofer, and an inductor in parallel with the tweeter, and you have a 12 dB/octave crossover.
" ...There should be no DC component present in a speaker signal. If one were, the speaker cone would experience a permanent deflection in one direction. ... "
You know what's scary? I think I actually understand that. Now I need to rethink my ideas as to how a signal behaves in a speaker.
If a magnet is rotated in a set of coils, AC current is created. And I understand how in THAT instance, current will reverse. But what creates current reversal in an amplifier circuit?
And besides .... there were 12VDC car radios in the '50s that used TUBES (VALVES). No AC there. No transformers. Yet they worked just fine. What gives?????????? jj
You know what's scary? I think I actually understand that. Now I need to rethink my ideas as to how a signal behaves in a speaker.
If a magnet is rotated in a set of coils, AC current is created. And I understand how in THAT instance, current will reverse. But what creates current reversal in an amplifier circuit?
And besides .... there were 12VDC car radios in the '50s that used TUBES (VALVES). No AC there. No transformers. Yet they worked just fine. What gives?????????? jj
" ... Series Vs Parallel Crossovers .... "
Thank you! That was another matter that I had never understood. That site makes the explanation clear, and understanding easy!
Damn! I'm getting an education here today! I may be bruised, battered and beaten in the end, but at least I'll be better informed! jj
Thank you! That was another matter that I had never understood. That site makes the explanation clear, and understanding easy!
Damn! I'm getting an education here today! I may be bruised, battered and beaten in the end, but at least I'll be better informed!
jj
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.