Indeed, I'm more curious about that infrasonic behavior. Wondering if it's a byproduct of the measurement system, or what. Obviously the impedance shouldn't dip below Re of the driver. Oh, nice woodwork btw, lest I should sound wholly negative, I'm just curious about the rather odd aspects- awfully tough to get a response THAT flat (not counting the downward slope) even with extreme crossovers. 
Perhaps we are seeing some funky EMF artifacts with the goofy infrasonic behavior?
Perhaps we are seeing some funky EMF artifacts with the goofy infrasonic behavior?
The crossover schematic should go some way towards explaining the frequency response:
Although my crossover design skills have improved significantly in the last few months, due in no small part to hours spent playing with the simulator in Speaker Workshop, this one wasn't designed by me. Credit for this design goes to Troels Gravesen . He is very adept at designing crossovers with the 'BBC Dip'. My upper hearing registers are still very good, despite spending most of my working life so far in industry of one sort or another. Hence, I find flat responses too 'tizzy'. The slight downward slope is much more suited to my long-term listening enjoyment.
An externally hosted image should be here but it was not working when we last tested it.
Although my crossover design skills have improved significantly in the last few months, due in no small part to hours spent playing with the simulator in Speaker Workshop, this one wasn't designed by me. Credit for this design goes to Troels Gravesen . He is very adept at designing crossovers with the 'BBC Dip'. My upper hearing registers are still very good, despite spending most of my working life so far in industry of one sort or another. Hence, I find flat responses too 'tizzy'. The slight downward slope is much more suited to my long-term listening enjoyment.
badman said:
I really wouldn't be worried about it. Its very likely to be measurement setup related.
There's nothing in the crossover to suggest that it would cause the impedance to drop as such and I really doubt scanspeak would produce a mid-bass with such an impedance plot. There's also very little program material with <10hz content.
If its really bothering gfinlayson he could connect a multimeter up to the speaker, play 1-10hz sine waves and take measurements.
Hey, it's not bothering me. The soundcard isn't very capable below about 10 Hz from my measurements with RMAA, so as far as I'm concerned any oddities below 10 Hz aren't worth worrying about. I have to say I'm quite impressed with my sound card's upper frequency capabilities, though - it's pretty much ruler flat up to 22 kHz,
Veneering underway...
3rd side panel veneered, and 4th coated with glue ready to veneer.
All four side panels are now complete; fronts, backs and tops will be done tomorrow.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
3rd side panel veneered, and 4th coated with glue ready to veneer.
All four side panels are now complete; fronts, backs and tops will be done tomorrow.
Simon5 got it. The pics are hosted off my own webspace, I use the img tags to display the thumbnail, and the url= tag to link to the main photo.
I'll hopefully start the finishing in the next few days. One front panel is now completed, and the glue is rolled out and setting up for the next one.
I'll hopefully start the finishing in the next few days. One front panel is now completed, and the glue is rolled out and setting up for the next one.
I've now got all the veneer on, and wet sanded the cabinets down to 600 grit with white spirit. I'll probably start with the finishing oil tomorrow.
This is a photo of the cabinets after sanding the first one with white spirit. It gives a good idea of how the grain will look when the finishing oil has been applied.
This is a photo of the cabinets after sanding the first one with white spirit. It gives a good idea of how the grain will look when the finishing oil has been applied.
An externally hosted image should be here but it was not working when we last tested it.
And finally.......
After 8 coats of finishing oil, two coats of creamed bees wax, and copious amounts of elbow grease, they're finally finished:
Time to sit back and enjoy with an old friend:
Graeme
After 8 coats of finishing oil, two coats of creamed bees wax, and copious amounts of elbow grease, they're finally finished:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Time to sit back and enjoy with an old friend:
An externally hosted image should be here but it was not working when we last tested it.
Graeme
Vikash,
The measurements are on post #17, and crossover schematic is on post #22.
The crossovers were built using Ampohm FP-CA-AU capacitors sourced from RS Components bypassed by 0.01 uF MKP 1837 caps. These are recommended by Tony Gee. From blind tests assisted by Mrs. Finlayson, I can confirm that they make a significant difference to the sound. Better detail and 'transparency'. Well worth the cost of 55 pence each. Inductors are all very low Rdc Intertechnik air core types with the exception of the 3.9 mH in the notch filter which is ferrite cored. Resistors are all 10W MOX. Inductors and resistors were bought from Strassacker. They hold very good stocks, are very competitively priced, provide excellent service and delivered to the UK with in 3 days of order.
Internal wiring is 2.5 mm^2 QED silver anniversary, bought at a bargain price from eBay. It has thin polyethylene insulation, and its four spiral bundled construction made it easy to attach to the crossover components.
I've got the speakers set-up about 8 feet apart, and 9 feet from my listening position, toed in, with tweeters to the inside pointing at my shoulders.
Bass is full and deep (incredible really, given that it's only a 6 1/2" midwoofer), but also tight and 'punchy'. Midrange and treble are detailed, and clear without being bright. Overall, I'd say a fairly 'laid-back' presentation that's not fatiguing in the long term. The soundstage has good width and depth, with good placement of performers and instruments.
With good recordings, they really shine. With bad recordings, they are utterly ruthless. A few of my CDs will definitely have to go.....
I've thrown a page together with all the photos here.
Thanks,
Graeme
The measurements are on post #17, and crossover schematic is on post #22.
The crossovers were built using Ampohm FP-CA-AU capacitors sourced from RS Components bypassed by 0.01 uF MKP 1837 caps. These are recommended by Tony Gee. From blind tests assisted by Mrs. Finlayson, I can confirm that they make a significant difference to the sound. Better detail and 'transparency'. Well worth the cost of 55 pence each. Inductors are all very low Rdc Intertechnik air core types with the exception of the 3.9 mH in the notch filter which is ferrite cored. Resistors are all 10W MOX. Inductors and resistors were bought from Strassacker. They hold very good stocks, are very competitively priced, provide excellent service and delivered to the UK with in 3 days of order.
Internal wiring is 2.5 mm^2 QED silver anniversary, bought at a bargain price from eBay. It has thin polyethylene insulation, and its four spiral bundled construction made it easy to attach to the crossover components.
I've got the speakers set-up about 8 feet apart, and 9 feet from my listening position, toed in, with tweeters to the inside pointing at my shoulders.
Bass is full and deep (incredible really, given that it's only a 6 1/2" midwoofer), but also tight and 'punchy'. Midrange and treble are detailed, and clear without being bright. Overall, I'd say a fairly 'laid-back' presentation that's not fatiguing in the long term. The soundstage has good width and depth, with good placement of performers and instruments.
With good recordings, they really shine. With bad recordings, they are utterly ruthless. A few of my CDs will definitely have to go.....
I've thrown a page together with all the photos here.
Thanks,
Graeme
Well, I went around to Graeme's with a few beers tonight, and I have to say, they look as good in real life as they do in the pics, a very nice veenering job indeed.
They don't sound half bad either, in case you're wondering. Graeme's description from earlier is accurate, they are very good drivers, with a nice crossover implementation, and they coped very well with one of my system torture tracks, (heartbeat drum song by Robbie Robertson), a nasty combination of accoustic hand drums and female vocals. I would certainly give them space in my house. The only drawback was that they really showed the faults in his listening room, (though that is a work in progress), with some quite prominent room resonances. He did insist on playing James Blunt, but I'll forgive him, 'cos he had some nice Summer Ale in stock.
They don't sound half bad either, in case you're wondering. Graeme's description from earlier is accurate, they are very good drivers, with a nice crossover implementation, and they coped very well with one of my system torture tracks, (heartbeat drum song by Robbie Robertson), a nasty combination of accoustic hand drums and female vocals. I would certainly give them space in my house. The only drawback was that they really showed the faults in his listening room, (though that is a work in progress), with some quite prominent room resonances. He did insist on playing James Blunt, but I'll forgive him, 'cos he had some nice Summer Ale in stock.
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