Cross-overs and switches
Thanks for your replies guys, I shure can use some backup. Point is that talking to yourself can make you being convinsed of what you just said as being the most logical song. Truths is, IT ISN'T...... (well most of the time anyways).
So much for self pitty, I found some wisdom on the Tannoy (Hilberink) website on modification of the cross-over network;
"My advise in this modification is:
a. Scrap the switches of a Monitor Gold's crossover network now, they are the cause of severe distortion. Mine even produced a rattling noise.
b. If you can get better capacitors, replace the electrolytic ones, colouration of the sound is reduced dramatically, depending on the quality of the new caps used.
c. If you can get better capacitors, replace the 6.8 uF ones, high frequencies get freshened up substantialy, sound gets more clear and crisp, depending on the quality of the caps used.
d. Remove the external multi-wiring of the crossover network (between panelswitches and crossover, leave the wiring between crossover and speaker, leave also the speakerconnector) and replace it with decent copper* wiring capable of handling 100 Watts, the lows get better considerably.
*(do not use silver wire because of corrosion and soldering characteristics, do you have experience with the Hitachi transistor 2SC460 in for example Luxman tuners? If you do, you know what I mean)."
End of wisdom.....
Now, 2 questions, please give your honest opinion here
;
1 - About scrapping the switches, I'm all in favor, mechanical "lose" connections in a cross-over looks far from ideal to me. What is the point anyway, if you design a cross-over for a fixed set of drivers in a fixed cabinet, of having switches to change the characteristics of the set. I would go for measuring and matching the components of the cross-over to have a flat response for the set.
2 - How about cabling, the Tannoy's I have use very thin "old" wire. Replace with e.g. Van Hull or other type of serious cabling? Is the "silver comment" for the cabling a valid point, making copper the way to go?
Thanks.
b.t.w. the Volt speaker as a woofer in combination with these Tannoys keep running round in my mind.
Thanks for your replies guys, I shure can use some backup. Point is that talking to yourself can make you being convinsed of what you just said as being the most logical song. Truths is, IT ISN'T...... (well most of the time anyways).
So much for self pitty, I found some wisdom on the Tannoy (Hilberink) website on modification of the cross-over network;
"My advise in this modification is:
a. Scrap the switches of a Monitor Gold's crossover network now, they are the cause of severe distortion. Mine even produced a rattling noise.
b. If you can get better capacitors, replace the electrolytic ones, colouration of the sound is reduced dramatically, depending on the quality of the new caps used.
c. If you can get better capacitors, replace the 6.8 uF ones, high frequencies get freshened up substantialy, sound gets more clear and crisp, depending on the quality of the caps used.
d. Remove the external multi-wiring of the crossover network (between panelswitches and crossover, leave the wiring between crossover and speaker, leave also the speakerconnector) and replace it with decent copper* wiring capable of handling 100 Watts, the lows get better considerably.
*(do not use silver wire because of corrosion and soldering characteristics, do you have experience with the Hitachi transistor 2SC460 in for example Luxman tuners? If you do, you know what I mean)."
End of wisdom.....
Now, 2 questions, please give your honest opinion here
;1 - About scrapping the switches, I'm all in favor, mechanical "lose" connections in a cross-over looks far from ideal to me. What is the point anyway, if you design a cross-over for a fixed set of drivers in a fixed cabinet, of having switches to change the characteristics of the set. I would go for measuring and matching the components of the cross-over to have a flat response for the set.
2 - How about cabling, the Tannoy's I have use very thin "old" wire. Replace with e.g. Van Hull or other type of serious cabling? Is the "silver comment" for the cabling a valid point, making copper the way to go?
Thanks.
b.t.w. the Volt speaker as a woofer in combination with these Tannoys keep running round in my mind.
A small step for man-kind, a Hugh leap for me
At last, I have Bass Box Pro, Woofer tester 2 and X Over Pro in the post box.
Also, added software called "Parallels Desktop" on my iMac, which emulates a windows environment on the Mac. Installed Windows 7 into that, installed the design and measuring software. It all works, so there is no need for a separate Windows PC next to my Mac (love Mac's, stable, easy to use, no fuzz, uuhhh OK almost no fuzz).
So I am ready and good to go.
I designed a bass reflex cabinet for a set of Faital Pro 12PR300's, these are waiting for their final destination in one of my small as possible PA subs, branded WAE portable PA. You can stuff a complete 2,5 kW PA (1 or 2 subs and 2 to 4 tops) in the back of your car and run a complete band over it, including drums. The tops are 4 x 4" full range speaker, closed cabinet, run from 180 Hz upward. Class D Crown amps with DSP.
Anyway, the cabinet is 87 liters (including a 20 liters sealed enclosure for the Tannoy Coaxial). On paper it runs from 29 Hz to 18 kHz +- 3 dB, max 300 watt. Would make a perfect studio monitor, Faitals are reasonably priced.
Maybe I wil start a build this weekend. These boxes are no rocket science
Next to that, my interest in a Transmission Line is growing by the day, and although I don't have any experience at all, I'm going for a TL. Have to figure out how to incorporate the sealed enclosure for the Tannoy in a TL design. both 12 inched's (12 " Tannoy + 12 inch low-free driver to unload the Tannoy from say 160 or so downwards) should be placed close to each other to make one single source. PMC's are very inspiring, complete different speaker set-up however.
The production version could be a modern 8 - 12 inch coaxial (B&C / Faital / ??) and maybe Volt 12" or if the Faital delivers, go for the best of the 12" series. The have very good price / performance, at least in my recent projects and PA's build.
Keep you posted.
At last, I have Bass Box Pro, Woofer tester 2 and X Over Pro in the post box.
Also, added software called "Parallels Desktop" on my iMac, which emulates a windows environment on the Mac. Installed Windows 7 into that, installed the design and measuring software. It all works, so there is no need for a separate Windows PC next to my Mac (love Mac's, stable, easy to use, no fuzz, uuhhh OK almost no fuzz).
So I am ready and good to go.
I designed a bass reflex cabinet for a set of Faital Pro 12PR300's, these are waiting for their final destination in one of my small as possible PA subs, branded WAE portable PA. You can stuff a complete 2,5 kW PA (1 or 2 subs and 2 to 4 tops) in the back of your car and run a complete band over it, including drums. The tops are 4 x 4" full range speaker, closed cabinet, run from 180 Hz upward. Class D Crown amps with DSP.
Anyway, the cabinet is 87 liters (including a 20 liters sealed enclosure for the Tannoy Coaxial). On paper it runs from 29 Hz to 18 kHz +- 3 dB, max 300 watt. Would make a perfect studio monitor, Faitals are reasonably priced.
Maybe I wil start a build this weekend. These boxes are no rocket science
Next to that, my interest in a Transmission Line is growing by the day, and although I don't have any experience at all, I'm going for a TL. Have to figure out how to incorporate the sealed enclosure for the Tannoy in a TL design. both 12 inched's (12 " Tannoy + 12 inch low-free driver to unload the Tannoy from say 160 or so downwards) should be placed close to each other to make one single source. PMC's are very inspiring, complete different speaker set-up however.
The production version could be a modern 8 - 12 inch coaxial (B&C / Faital / ??) and maybe Volt 12" or if the Faital delivers, go for the best of the 12" series. The have very good price / performance, at least in my recent projects and PA's build.
Keep you posted.
TL design rules and observations
Found the following on the WEB, many thanks to Jon Risch;
Classic TL Design -- Jon Risch
Transmission Line Speakers Read Me
pointing to :
Quarter Wavelength Loudspeaker Design
Also found software:
Leonard Audio | Audio Engineering Resources
Very useful software from my first attempts. Questions will be, does it sound as it looks. What drew my attention was the ability to "break-up the pipe in segments, fold it any way you want and experiment with stuffing to create the "ideal" TL on paper. Should be a nice starting point ?!?! In case it works out well, He will deserve a donation
ANY other hints?
Found the following on the WEB, many thanks to Jon Risch;
Classic TL Design -- Jon Risch
Transmission Line Speakers Read Me
pointing to :
Quarter Wavelength Loudspeaker Design
Also found software:
Leonard Audio | Audio Engineering Resources
Very useful software from my first attempts. Questions will be, does it sound as it looks. What drew my attention was the ability to "break-up the pipe in segments, fold it any way you want and experiment with stuffing to create the "ideal" TL on paper. Should be a nice starting point ?!?!
In case it works out well, He will deserve a donation ANY other hints?
TL setup sketch
Here is my initial thought.
I didn't want to place any objects IN the TL, so placed the Tannoy coaxial on top in a separate sealed enclosure, used the space behind the enclosure for the filter of the Tannoy (2-way original design filter, build with new state of the art components) and Neutric 4 pin Speakons. If I would place the sealed enclosure between the 12" low driver and the terminus, it would block the pipe and I don't have a clou on the result for the TL behavior but my guess is, that screws up the complete TL concept.
The TL is a 3 fold front firing device, straight pipe.
First attempts with the software give me 80 x 60 x 40 (rough figures) TL, 32 x 32 x 25 sealed box on top. So the box is 112 cm high.
SPL graph shows 30 - 250 Hz nearly flat, with slow roll-off after some stuffing experiments. Mid bass bumps seem to be changeable with stuffing
I want to drive this set with a 300 watt class D amp with DSP, crossed somewhere around or just below 200 Hz to help the Tannoy survive serious beating. The Tannoy will be driven through the passive filter, as designed by Tannoy.
So this makes a 3-way box, bi-wired and driven. This arrangement should result in a single point source driver system (coax = point source, 12 " within less than ¼ wavelength (42,5 cm for 200 Hz) of each other should also behave as a point source.)
How is that for a start?
Here is my initial thought.
I didn't want to place any objects IN the TL, so placed the Tannoy coaxial on top in a separate sealed enclosure, used the space behind the enclosure for the filter of the Tannoy (2-way original design filter, build with new state of the art components) and Neutric 4 pin Speakons. If I would place the sealed enclosure between the 12" low driver and the terminus, it would block the pipe and I don't have a clou on the result for the TL behavior but my guess is, that screws up the complete TL concept.
The TL is a 3 fold front firing device, straight pipe.
First attempts with the software give me 80 x 60 x 40 (rough figures) TL, 32 x 32 x 25 sealed box on top. So the box is 112 cm high.
SPL graph shows 30 - 250 Hz nearly flat, with slow roll-off after some stuffing experiments. Mid bass bumps seem to be changeable with stuffing
I want to drive this set with a 300 watt class D amp with DSP, crossed somewhere around or just below 200 Hz to help the Tannoy survive serious beating. The Tannoy will be driven through the passive filter, as designed by Tannoy.
So this makes a 3-way box, bi-wired and driven. This arrangement should result in a single point source driver system (coax = point source, 12 " within less than ¼ wavelength (42,5 cm for 200 Hz) of each other should also behave as a point source.)
How is that for a start?
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Correct, I used emulator as my best english for a VM environment (emulating hardware...).
It's just a sketch, have to figure out the best place for the driver yet. At least, if that's what you mean by offset...
After a few first experiments with the "transmission line" software, it seems that a 4 fold TL with a driver offset of 85 cm looks promising (minimal rimples from 100 Hz upwards).
I will post some pics this weekend.
The Fs of this 12PR300 is 50 Hz, which seems to be on the high side. Gives a slow roll-of, which may even workout nice for the sound character of this first TL I'm trying to figure out.
Suggestions always welcome, learning learning...
TL design
I took a first shot at trying to figure out a TL for the Faital Pro 12PR300.
After some iterations I came up with a 5 fold scheme with both the driver and the terminus at the front of the enclosure and the driver close to the top / bottom of the cabinet. I want to "couple" this driver with the Tannoy coaxial so it needs to be close to the edge of the cabinet.
I got a 250 cm pipe that i denied in 5 elements of 50 cm. This folds nicely into a cabinet of 83 x 50 cm (internal measures). Then I experimented with the density of the foam and got a TL that runs from 29 to 160 Hz +- 3dB.
I added a drawing and the SPL / impedance / Phase / Group Delay and cone displacement graphs.
Question is, is the "used" density foam in this model commercially available (or to be made).
Looks like a nice candidate for some saw-dust
I took a first shot at trying to figure out a TL for the Faital Pro 12PR300.
After some iterations I came up with a 5 fold scheme with both the driver and the terminus at the front of the enclosure and the driver close to the top / bottom of the cabinet. I want to "couple" this driver with the Tannoy coaxial so it needs to be close to the edge of the cabinet.
I got a 250 cm pipe that i denied in 5 elements of 50 cm. This folds nicely into a cabinet of 83 x 50 cm (internal measures). Then I experimented with the density of the foam and got a TL that runs from 29 to 160 Hz +- 3dB.
I added a drawing and the SPL / impedance / Phase / Group Delay and cone displacement graphs.
Question is, is the "used" density foam in this model commercially available (or to be made).
Looks like a nice candidate for some saw-dust
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Tannoy SRM12x reconstruction?
So, I goy my woofer tester software and hardware. I did measure both K3149, they did not end up "identical" Anyway, for the box, it was not a real difference, so I made up the following sketch. End up close to "real" cabinet, except for the bass reflex, mine is a tad bigger (low vent air speed).
I added braces, don't know how the original internals looked like. I do know the particle board wood they used at that time was "crap" compared to what we use now. I know, I build boxes in that period. They used 25mm thick particle board for the front panel. I stick to 18 mm MDF and add braces around the speaker frame back side.
See attachment.
Yes, it does not go much deeper than 50-ish Hz +- 3dB with 73 liters. Adding volume fils up this quitte steep roll-of, but only from like 120 liters up to 200 liters makes a noticeble difference.
I added a graph with the 73 liter plot (orange) and the 200 liter plot (yellow). This shows whats happening. The driver suffers however, which most likely want make it sound better overall. That must be the reason why they did not make this a real BIG box. Soffit mounting the 73 liters is a peace of cake, it does not require much room. AND adds to the low end, may-be even filling this roll-of gap
It seems like it's a designers choice, to support the driver, produce sufficient lows and small enough NOT to fill all the studio space. (My opinion).
My thought was, WHY make it 200 liters? They used these boxes to produce PILES of hits and nice sounding recordings at that time.
My plans to make it part of a larger TL as mid-high have changed. I want to make this one as close to original as it was and soffit mount it in my (ever to build) home studio. Even use the same veneer and color scheme.
I DO feel the need for a new thread for a studio monitor, based on a TL and using "cheap-but-best" components. See how that works out.
So, I goy my woofer tester software and hardware. I did measure both K3149, they did not end up "identical" Anyway, for the box, it was not a real difference, so I made up the following sketch. End up close to "real" cabinet, except for the bass reflex, mine is a tad bigger (low vent air speed).
I added braces, don't know how the original internals looked like. I do know the particle board wood they used at that time was "crap" compared to what we use now. I know, I build boxes in that period. They used 25mm thick particle board for the front panel. I stick to 18 mm MDF and add braces around the speaker frame back side.
See attachment.
Yes, it does not go much deeper than 50-ish Hz +- 3dB with 73 liters. Adding volume fils up this quitte steep roll-of, but only from like 120 liters up to 200 liters makes a noticeble difference.
I added a graph with the 73 liter plot (orange) and the 200 liter plot (yellow). This shows whats happening. The driver suffers however, which most likely want make it sound better overall. That must be the reason why they did not make this a real BIG box. Soffit mounting the 73 liters is a peace of cake, it does not require much room. AND adds to the low end, may-be even filling this roll-of gap
It seems like it's a designers choice, to support the driver, produce sufficient lows and small enough NOT to fill all the studio space. (My opinion).
My thought was, WHY make it 200 liters? They used these boxes to produce PILES of hits and nice sounding recordings at that time.
My plans to make it part of a larger TL as mid-high have changed. I want to make this one as close to original as it was and soffit mount it in my (ever to build) home studio. Even use the same veneer and color scheme.
I DO feel the need for a new thread for a studio monitor, based on a TL and using "cheap-but-best" components. See how that works out.
Attachments
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Hi - i will follow this thread with interest as i have a pair of 3149 waiting to be reconed with Lockwood cones. They are the dual magnet type.
Charles' advice to add another 12' (or even15') for bass looks like sound advice to me and this is most probably what i will do. I seem to recall a thread by mpmarino (?) here with box indications, crossover settings you should look it up and maybe contact him?
Best wishes for your build!
Charles' advice to add another 12' (or even15') for bass looks like sound advice to me and this is most probably what i will do. I seem to recall a thread by mpmarino (?) here with box indications, crossover settings you should look it up and maybe contact him?
Best wishes for your build!
Small aside;
My neighbour had a pair of SRMs (he bought 'em new) .
While decent speakers, they were markedly inferior to my Golds in 175 ltre boxes.
A pair of DMT's performed Much better as well.
I'd try and clone dmt's, years before bothering with a SRM.
DMT II's featured twin 15's... If Bass is of concern.
Basically: SRMs were not quite as good as the Brochure Babbles suggested.
Merely a bit of reality to your expectations.
My neighbour had a pair of SRMs (he bought 'em new) .
While decent speakers, they were markedly inferior to my Golds in 175 ltre boxes.
A pair of DMT's performed Much better as well.
I'd try and clone dmt's, years before bothering with a SRM.
DMT II's featured twin 15's... If Bass is of concern.
Basically: SRMs were not quite as good as the Brochure Babbles suggested
.Merely a bit of reality to your expectations.
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Alternative, 2x 12" with K3149
Yes, it's obvious. The original SRM12X wasn't a bass monster. Charles option is a very nice one, although moves away from the initial idea of this thread. I got the K3149's at a reasonable price and wanted to recreate a set of SRM12X.
That's what I will do anyway, make some saw dust and there they are. It's a simple box. As stated earlier, I would like to hear them in a Soffit Mount structure (sunk in the wall your are facing with the speaker panel plane leveled to the surface of the wall). As this eliminates rear reflections of low freq's of a cabinet close in front of a wall, it also add 6dB in the low end. A good soffit mount will also have a bass trap UNDER the soffit mounted speaker to "eat some of that added low", you can tune the additional dB's. That will make the SRM12X act like a 150 liters version while being a 73 liter cabinet. Now, that's a nice idea? Also because the soffit mount requires the wall to be at least the dept of the cabinet moved inwards of the room, you want a "undeep as possible" cabinet.
Now for C73 reply "Hi - i will follow this thread with interest as i have a pair of 3149 waiting to be reconed with Lockwood cones. They are the dual magnet type.
Charles' advice to add another 12' (or even15') for bass looks like sound advice to me and this is most probably what i will do. I seem to recall a thread by mpmarino (?) here with box indications, crossover settings you should look it up and maybe contact him?
Best wishes for your build!"
How about the design in the attachment? It's an 80 liter bass reflex cabinet for a Faital Pro 12PR300 BUT, added with a 15 liter CLOSED cabinet with the K3149 tuned at 160 Hz.
Bottom line here, ALMOST SAME SIZE as the SRM12X (slightly wider and deeper), LOTS of low end added, friendly priced (around 130 euro for the Faital). It is 18 mm birch ply 13 layers BB quality. Could be loaded by a Hypex PSC2.400 plate amp and a passive filter for the Tannoy. The Hypex has a DSP and is dual amp 2x 200 watt @ 8 ohm. Crossed at 160 Hz with the DSP and the passive crossover as designed by Tannoy for the K3149, but with NEW components to make it a top filter. The DSP can be used to flatten the combination if required. Would that be a killer?
Yes, it's obvious. The original SRM12X wasn't a bass monster. Charles option is a very nice one, although moves away from the initial idea of this thread. I got the K3149's at a reasonable price and wanted to recreate a set of SRM12X.
That's what I will do anyway, make some saw dust and there they are. It's a simple box. As stated earlier, I would like to hear them in a Soffit Mount structure (sunk in the wall your are facing with the speaker panel plane leveled to the surface of the wall). As this eliminates rear reflections of low freq's of a cabinet close in front of a wall, it also add 6dB in the low end. A good soffit mount will also have a bass trap UNDER the soffit mounted speaker to "eat some of that added low", you can tune the additional dB's. That will make the SRM12X act like a 150 liters version while being a 73 liter cabinet. Now, that's a nice idea? Also because the soffit mount requires the wall to be at least the dept of the cabinet moved inwards of the room, you want a "undeep as possible" cabinet.
Now for C73 reply "Hi - i will follow this thread with interest as i have a pair of 3149 waiting to be reconed with Lockwood cones. They are the dual magnet type.
Charles' advice to add another 12' (or even15') for bass looks like sound advice to me and this is most probably what i will do. I seem to recall a thread by mpmarino (?) here with box indications, crossover settings you should look it up and maybe contact him?
Best wishes for your build!"
How about the design in the attachment? It's an 80 liter bass reflex cabinet for a Faital Pro 12PR300 BUT, added with a 15 liter CLOSED cabinet with the K3149 tuned at 160 Hz.
Bottom line here, ALMOST SAME SIZE as the SRM12X (slightly wider and deeper), LOTS of low end added, friendly priced (around 130 euro for the Faital). It is 18 mm birch ply 13 layers BB quality. Could be loaded by a Hypex PSC2.400 plate amp and a passive filter for the Tannoy. The Hypex has a DSP and is dual amp 2x 200 watt @ 8 ohm. Crossed at 160 Hz with the DSP and the passive crossover as designed by Tannoy for the K3149, but with NEW components to make it a top filter. The DSP can be used to flatten the combination if required. Would that be a killer?
little after burner
Ooh yeah, forgot:
The Tannoy K3149 of course is already point source. This cabinet positions both drivers close enough to ALSO make them act like a point source. Center of both drivers closer than ¼ wavelength of 160 Hz.
So here we have a point source cabinet, that should become a very nice studio monitor or home audio speaker.
MOST likely there will be a need to fiddle around with the DSP to tame the tweeter of the K3149. They can scream loud I was told, that's why Tannoy made the adjustable filter.
Ooh yeah, forgot:
The Tannoy K3149 of course is already point source. This cabinet positions both drivers close enough to ALSO make them act like a point source. Center of both drivers closer than ¼ wavelength of 160 Hz.
So here we have a point source cabinet, that should become a very nice studio monitor or home audio speaker.
MOST likely there will be a need to fiddle around with the DSP to tame the tweeter of the K3149. They can scream loud I was told, that's why Tannoy made the adjustable filter.
Looks very good Wae. I am at a much earlier stage than you as i have to buy the measurement tools (i just have an UMIK microphone and rew for now, not to mention my 3149 are still unconed). I am aiming more at domestic reproduction than monitoring, one thing that keeps turning in my mind is an OB à la Nelson Pass. It will depend on WAF... I have Icepower ASC200 modules at hand that i could use for Bass. Don't know yet for mid/high, am going to watch closely what you acheive with the passive crossovers. Best,
Thomas
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