From an example of an ordinary 2-way 8 ohm speaker. . .
The main question is the RC, since the new speaker with voice coils parallel will have removed some of the need of the RC. So, what I need to know is the RC value of a double-woofer version
8 ohm example:
Dayton Classic 6.5" woofer
across the poles Cap: 6.8u
across the poles RC 3.3u~15R
series with one pole Coil: 1.3mh
Cabinet is large and sealed, fiberous, and the only padding is one thick paper towel, which is attached to the back panel, directly back of the woofer. Cabinet face is 15"x23", with 3/4" fibrous board and the internal depth is 9".
The new speaker cabinet is planned to twice the internal volume for supporting double parallel woofers; however, feel free to voice other suggestions (that would fit a 1939 Crosley radio-grille wood bars spacing supports this particular size woofer). I mentioned cabinet specs because they're part of the crossover--they are an electronic portion of the crossover when-after the device is switched on and running.
4 ohm plan:
Two parallel Dayton Classic 6.5" woofers
across the poles Cap: 3.3u
across the poles RC: that's the question
series with one pole Coil: 0.68mh 14ga (already have it)
The amplifier was designed for bridged, but has been altered to SE mode; and that has made the expected operation, now a 4 ohm speaker. Also, I've made the tuner already (it wasn't as fast and easy as claimed, as the labor was unspeakably irritating, although it does haul in a station clearly for every spot on the dial, finally, and I had run short of invectives well before then). The hard part seems to be the speaker. I have now gained even more respect for those who have managed the goodly speakers!
A relevant concern:
The change from just one woofer to paralleling two of same, has made the RC less necessary; thus, the proper RC value for the double-woofer 4 ohm example does not relate to the previous one-woofer 8 ohm example.
It is not in any way similar.
It is just like I had installed a far better quality woofer that happens to be 4 ohms. I have already prepared for the fact that a 4 ohm load could seriously degrade the performance (and efficiency) of an amplifier that wasn't built for it, by using an amplifier (and support circuits) that have already been succeeding with a 4 ohm load as expected usage.
The problem is that the woofer RC value can't be translated easily because paralleling the woofers has decreased the need of the RC. Doubling the woofers to run tandem, is just exactly like swapping in a larger, higher quality woofer, that just happens to be 4 ohms. That is why I can't even guess the relevant RC value.
Might there be a chart for this?
The main question is the RC, since the new speaker with voice coils parallel will have removed some of the need of the RC. So, what I need to know is the RC value of a double-woofer version
8 ohm example:
Dayton Classic 6.5" woofer
across the poles Cap: 6.8u
across the poles RC 3.3u~15R
series with one pole Coil: 1.3mh
Cabinet is large and sealed, fiberous, and the only padding is one thick paper towel, which is attached to the back panel, directly back of the woofer. Cabinet face is 15"x23", with 3/4" fibrous board and the internal depth is 9".
The new speaker cabinet is planned to twice the internal volume for supporting double parallel woofers; however, feel free to voice other suggestions (that would fit a 1939 Crosley radio-grille wood bars spacing supports this particular size woofer). I mentioned cabinet specs because they're part of the crossover--they are an electronic portion of the crossover when-after the device is switched on and running.
4 ohm plan:
Two parallel Dayton Classic 6.5" woofers
across the poles Cap: 3.3u
across the poles RC: that's the question
series with one pole Coil: 0.68mh 14ga (already have it)
The amplifier was designed for bridged, but has been altered to SE mode; and that has made the expected operation, now a 4 ohm speaker. Also, I've made the tuner already (it wasn't as fast and easy as claimed, as the labor was unspeakably irritating, although it does haul in a station clearly for every spot on the dial, finally, and I had run short of invectives well before then). The hard part seems to be the speaker. I have now gained even more respect for those who have managed the goodly speakers!
A relevant concern:
The change from just one woofer to paralleling two of same, has made the RC less necessary; thus, the proper RC value for the double-woofer 4 ohm example does not relate to the previous one-woofer 8 ohm example.
It is not in any way similar.
It is just like I had installed a far better quality woofer that happens to be 4 ohms. I have already prepared for the fact that a 4 ohm load could seriously degrade the performance (and efficiency) of an amplifier that wasn't built for it, by using an amplifier (and support circuits) that have already been succeeding with a 4 ohm load as expected usage.
The problem is that the woofer RC value can't be translated easily because paralleling the woofers has decreased the need of the RC. Doubling the woofers to run tandem, is just exactly like swapping in a larger, higher quality woofer, that just happens to be 4 ohms. That is why I can't even guess the relevant RC value.
Might there be a chart for this?
Can we look at it with voice coil inductance as the point and purpose for the RC?
That goes to half in a double woofer example. Less voice coil inductance at the woofer, also decreases the need of the RC. So, the RC will not need to be at double the current.
Usually, when doubling the loading, you won't get 1/4, won't get 1/2 and won't get 4x, but rather more like 1/3rd, 2/3rds or 3x, as more plausible expectations for most electronics. You know, if claimed 4x, its probably 3x instead. You get a lot of bonus/parasitic "R's" when the loading is doubled. And, with two coils run parallel, you sure do get half the inductance.
Then 4u7-10R is maximum current for the new crossover's RC. That was the maximum plausible; although, the optimal figure is beyond my ability to calculate.
That goes to half in a double woofer example. Less voice coil inductance at the woofer, also decreases the need of the RC. So, the RC will not need to be at double the current.
Usually, when doubling the loading, you won't get 1/4, won't get 1/2 and won't get 4x, but rather more like 1/3rd, 2/3rds or 3x, as more plausible expectations for most electronics. You know, if claimed 4x, its probably 3x instead. You get a lot of bonus/parasitic "R's" when the loading is doubled. And, with two coils run parallel, you sure do get half the inductance.
Then 4u7-10R is maximum current for the new crossover's RC. That was the maximum plausible; although, the optimal figure is beyond my ability to calculate.
A great weakness of D'Appolito designs in the 4 ohm bass impedance, IMO.
When you double up woofers to parallel MTM, you halve the bass coils and resistances, double the capacitors from the MT design on the bass circuit. Simple as that really.
And double the volume, and halve the port length.
Vifa PL14WJ-
When you wire in series to 16 ohms, it goes the other way. Series wired is easier, because the MT tweeter circuit is unchanged. Level is unchanged.
When you double up woofers to parallel MTM, you halve the bass coils and resistances, double the capacitors from the MT design on the bass circuit. Simple as that really.
And double the volume, and halve the port length.
Vifa PL14WJ-
When you wire in series to 16 ohms, it goes the other way. Series wired is easier, because the MT tweeter circuit is unchanged. Level is unchanged.
Attachments
One advantage is that you have the option to connect each 8ohm woofer to its own amp.
I'd have to buy two of 1.3mh coils (that I don't have) instead of the single 0.68mh coil (that I have already).
Except for expense, your plan does indeed have a good long list of merits.
It isn't just the expense of the two coils and several probably free caps and resistors; but, I'd actually like to learn by experiencing why the speaker designers are so steadfast/insistent with their double-woofer designs. This extra loading usually conflicts with basics of how to use an amplifier as well as most amplifier designers. And, if viewed from the amplifier design, it does look a bit crazy. However, I'd like to see/experience what this is like from the speaker designer's side. I owe that to some rather grand speaker engineers, and I may happen to be a bit tardy in actually doing it.
On the surface, it looks like the double-woofer designs just move some speaker expense and linearity trouble to the amplifier instead. However, it is possible that the leading speaker designers might be correct in the the linearity issue is better done at the amplifier and cost difference nillo had you wanted better audio quality anyway. I paraphrased a couple of cussouts for that one. But, I'm not one nor several of the best speaker designers; and, it is within my means to brace up an amplifier; so, I think it is worth a spin to find out what happens when if I paid attention to the speaker designers. I sort-of, kind-of, almost promised to do that or something quite similar.
There went with the long winded version of why I can't go with your first dose of advice, even though I'm entirely grateful to hear from you. The thing is that those woofers have to be hardwired paralleled.
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