I stand corrected. I once heard series crossovers put more strain on the drivers. Your explanation however, makes mathematical sense. A 1st order is a 1st order, regardless of which crossover is used.
'fraid so. Boring, but true. 
Re strain, depends how you define it, but if we assume equivalent filters, then the series type can expose the tweeter a little more as rejection of back EMF from the LF units usually isn't as good -nature of the beast. Unlikely to be a major issue in practice given the levels involved, but technically correct. Rod Elliot discusses it; that might be what you're thinking of: Series vs. Parallel Crossover Networks Series 1st order (only 1st order) does have its party-piece of maintaining flat electrical summing even with some impedance shifts in the drivers. Doesn't necessarily mean it will continue to sum flat acoustically of course. 😉
Re strain, depends how you define it, but if we assume equivalent filters, then the series type can expose the tweeter a little more as rejection of back EMF from the LF units usually isn't as good -nature of the beast. Unlikely to be a major issue in practice given the levels involved, but technically correct. Rod Elliot discusses it; that might be what you're thinking of: Series vs. Parallel Crossover Networks Series 1st order (only 1st order) does have its party-piece of maintaining flat electrical summing even with some impedance shifts in the drivers. Doesn't necessarily mean it will continue to sum flat acoustically of course. 😉
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Before I start testing the 2 Accuton C51's D'Appolito, I first need to quickly talk about my amplifiers.
I've been using the Atma-Sphere MA-1, 140W Dual Differential Tube amps for about 15 years.
Tube amps are current source components (some Solid State amps have current output chips instead of voltage output, but not many).
Tube amps differ from solid state with other than 8 ohm loads.
140W @ 8 ohm, only 120W @ 4 ohm, they won't drive a 2 ohm load without an autoformer. Their output impedance is 2.1 ohm.
We all know about solid state; assume the same 140W @ 8 ohm, 280W @ 4 ohm (more than twice that of a tube amp @4 ohm), 560W @ 2 ohms.
Staying with solid state; 70W @ 16 ohm, 35W @ 32 ohm, etc.
Tube amp; 160W @ 16 ohm, and 160W with everything higher. This will be very important when I finally get my dual AE TD8m's and dual PB15H+. More on that in the fall.
Now to measuring the D'Appolito.
I've been using the Atma-Sphere MA-1, 140W Dual Differential Tube amps for about 15 years.
Tube amps are current source components (some Solid State amps have current output chips instead of voltage output, but not many).
Tube amps differ from solid state with other than 8 ohm loads.
140W @ 8 ohm, only 120W @ 4 ohm, they won't drive a 2 ohm load without an autoformer. Their output impedance is 2.1 ohm.
We all know about solid state; assume the same 140W @ 8 ohm, 280W @ 4 ohm (more than twice that of a tube amp @4 ohm), 560W @ 2 ohms.
Staying with solid state; 70W @ 16 ohm, 35W @ 32 ohm, etc.
Tube amp; 160W @ 16 ohm, and 160W with everything higher. This will be very important when I finally get my dual AE TD8m's and dual PB15H+. More on that in the fall.
Now to measuring the D'Appolito.
Pic. 1) a single C51, full range, no safeties, less than 1W, 1000Hz to 20K.
Pic. 2) dual C51's, parallel wiring, microphone 1m, height is half way between them. Impedance will be 3 ohms as seen by the amps.
Pic. 3) dual, series wiring, 12 ohms as seen by the amps. Nice!
We will obviously be wiring the C51's in series. If you ever need to wire two drivers together, test for yourself. Some of you may have SS amps which are current source. I'd love to know how they behave.
Pic. 2) dual C51's, parallel wiring, microphone 1m, height is half way between them. Impedance will be 3 ohms as seen by the amps.
Pic. 3) dual, series wiring, 12 ohms as seen by the amps. Nice!
We will obviously be wiring the C51's in series. If you ever need to wire two drivers together, test for yourself. Some of you may have SS amps which are current source. I'd love to know how they behave.
Attachments
Here are the dual C51's, D'Appolito. Full range (no crossover), and in circuit with the spare AMT 5' away and wrapped in a blanket.
That rise between 1500Hz and 1900Hz followed by the valley around 2300Hz may be a kink in the armour. Let's hope the AE TD8m's have a rise in that region (ya, right?)
That rise between 1500Hz and 1900Hz followed by the valley around 2300Hz may be a kink in the armour. Let's hope the AE TD8m's have a rise in that region (ya, right?)
