)
The bipole cant point-source better since the reflected sound of the rear speaker creates a point the size of the rear wall. I have a switchable inductor on mine so I can use the rear driver below 150hz just for the LF help. It becomes a different speaker this way. And remember that if a bipole is placed close to the rear wall were the best LF reinforcement is, it destroys the midrange presentation.
As far as a dipole goes, they will probably always sound the most natural BUT implementation is always difficult. They have to be big, placed out in the room and little FRs next a pretty high XO so integrating the sub is tricky. A Basszilla concept is a good way to go.
My personal plan is to use the monopole and play with a 4th order BP stand w/o a crossover. Sort of a Whamodyne meets the LS35a sub.
http://home.freeuk.net/pwhatton/subs.html
Below is a winISD screenshot of a 1197BR and a 8" Dayton 4thBP. If the Fostex could be integrated, it could be a solid bottom end w/o passives. Just a thought.
amt
As far as a dipole goes, they will probably always sound the most natural BUT implementation is always difficult. They have to be big, placed out in the room and little FRs next a pretty high XO so integrating the sub is tricky. A Basszilla concept is a good way to go.
My personal plan is to use the monopole and play with a 4th order BP stand w/o a crossover. Sort of a Whamodyne meets the LS35a sub.
http://home.freeuk.net/pwhatton/subs.html
Below is a winISD screenshot of a 1197BR and a 8" Dayton 4thBP. If the Fostex could be integrated, it could be a solid bottom end w/o passives. Just a thought.
amt
Attachments
amt said:
by its very nature a bipole shouldn't be too close to the back wall -- particularily for bass reinforcement. If the speaker is far enuff out from the wall then any reflected sound should merge into the sound field and not be perceived as a source, making the bi-pole act like a mono-pole as far as direct sound goes... of course the bipole has flat power response.
Flipping the inductor in makes a 1.5 way with a monopole source on the top... power-response will be lean at the top -- having a switchable choke (or cap in the case of series wiring) is a good idea.... the filter should be sized to correspond with the baffle step.
dave
Dave, granted the sounds will merge but this is placing the speakers 4-5' into the room. Mine are about 2.5' in and there not much merging going on. There a night and day difference inductored/versus non. But I do hate losing the dbs.
BTW, dont you have BDs with the angled up rear driver? Have you compared that design with an opposed driver design. Ive wondered how the reflections change and each sound relative to each other . Ive actually hung t-shirts and such over the back speaker for tweakng purposes. Looks bad but sounds good. This is a poor mans' inductor.
amt
BTW, dont you have BDs with the angled up rear driver? Have you compared that design with an opposed driver design. Ive wondered how the reflections change and each sound relative to each other . Ive actually hung t-shirts and such over the back speaker for tweakng purposes. Looks bad but sounds good. This is a poor mans' inductor.
amt
amt said:
We compared those against Tim's BP 1197 ML-Voigts... Tim's speaker was decididly better... in my room 2.5 ft is as close as i can get my speakers to the back wall when i'm tucking them in... 4-5' is normal and optimum room placement (i'd have to flip the whole room around again -- currently as is for SAF and to accomodate a TV monitor) they are more like 6' out (24' x 16' main room -- with another 8' x 24' mostly open next to it, and another 12'x24' space open on the end)
dave
gmilitano said:
The driver offset from the end of the line is used to kill the 1st undesirable line harmonic... its placement is critical....
An example of the folded one has been posted -- Post #95 (althou may need to adjusted for length -- still haven't dug out Denson's paper + we've increased line length from 30 to 32")
dave
Timn8ter said:
planet10 said:
I have read over Nelson Pass's article regarding Current Source amps and Sensitive Full-Range Drivers.
http://www.firstwatt.com/current_source_amps_1.htm
Anyway, I think this is a must read for anyone interested in full range drivers.
The article does not cover the FE127E, but does look at the FE108E Sigma driver, which is similar to the FE127E. The article shows a much improved response of this driver with a current source amp + parallel network. The article explains that the network can be simplified as a single resistor.
Using that info, the optimal speaker wire for this driver may be a small diameter wire (high gauge).
Cheers,
Gio.
folded volume
Hello dave:
I was studying the diagram from post 96. It may be an artifact of the sketch but it looks like the volume between the drivers is a little high. Could you check, I think the volume on the right side has been double counted.
I really like this presentation, I am thinking it would look similar to my current MLTL if I extend the sides. I checked with M last night and she likes the presentation as well. I may end up with a fleet of Fostex speakers. A bit of a stereo design showroom so to speak. All I need is a handmade tube amp or current source amp.
Hello dave:
I was studying the diagram from post 96. It may be an artifact of the sketch but it looks like the volume between the drivers is a little high. Could you check, I think the volume on the right side has been double counted.
I really like this presentation, I am thinking it would look similar to my current MLTL if I extend the sides. I checked with M last night and she likes the presentation as well. I may end up with a fleet of Fostex speakers. A bit of a stereo design showroom so to speak. All I need is a handmade tube amp or current source amp.
Re: folded volume
96 is an alpha drawing of #98 which is more correctly as Tim envisioned it (he specified the dimensions -- i noted to myself that the partition is 6" from the top and 5 out from the sides). This design has the issue of the 2 drivers having different offsets from th ened of the line... this means that a model (with 2 driver equivalent firing out the top) is not necessarily going to as accurately portray things as a design where the 2 drivers have the same offset... it could work great thou.
dave
SCD said:
96 is an alpha drawing of #98 which is more correctly as Tim envisioned it (he specified the dimensions -- i noted to myself that the partition is 6" from the top and 5 out from the sides). This design has the issue of the 2 drivers having different offsets from th ened of the line... this means that a model (with 2 driver equivalent firing out the top) is not necessarily going to as accurately portray things as a design where the 2 drivers have the same offset... it could work great thou.
dave
I replaced my brine's internal wiring by a pair of cat5 it does improved over all . From the very begining my "bass" set up is +12 and +12 on the high(treble), but now I end up to +4 on the bass and +2 on treble on my AVR big improvement, though. And early yesterday I move my speaker from short wall to wide wall(and seeking for best placed),
big improvement as well on bass and improve sound stage and more livelier and dynamic. And my last tweak I put ceramic tiles on top of it about 8pcs both speaker(it's too heavy) and I'm surprised on the bass, its get tighter trust me to this. I remember Bob Brines recommend to double, the top panel or damping material(mine only used one tile), but my wife does'nt liked it
.Supposed to be, those ceramic tiles will be use on our terrace flooring, I'm just curious so I used it first ... hehehe.
And the last word I heard to my wife is... WHAT NEXT
big improvement as well on bass and improve sound stage and more livelier and dynamic. And my last tweak I put ceramic tiles on top of it about 8pcs both speaker(it's too heavy) and I'm surprised on the bass, its get tighter trust me to this. I remember Bob Brines recommend to double, the top panel or damping material(mine only used one tile), but my wife does'nt liked it
.Supposed to be, those ceramic tiles will be use on our terrace flooring, I'm just curious so I used it first ... hehehe.And the last word I heard to my wife is... WHAT NEXT