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In Reply to: Notch filter for TAD TD4001 posted by fatbottle on February 16, 2007 at 08:05:29:
Hi !Well, 4mH+15uF looks like a Linkwitz Riley 2nd order crossover at 650 Hz for....8 ohms mean impedance at the crossover frequency.
As far as I know, TD4001 is more like 16 ohms. I would enjoy to get an impedance curve of the 4001 on the azura horns.
Maybe your passive crossover is the explanation of the "shout" effect ?
A man in taiwan sells clones of the TN-2 crossover network :))) it would be interresting to get the schematic !
Follow Ups:
'Well, 4mH+15uF looks like a Linkwitz Riley 2nd order crossover at 650 Hz for....8 ohms mean impedance at the crossover frequency'Yes thats correct ! You may also be correct that the shout is caused by the crossover but I doubt there will be too much interaction as the LPAD is set as an overall 8 ohms . The TAD is connected to a ladder of 0.2 ohm resistors so various settings can be tried . At present it's all 'cold welded' together in terminal blocks so is very easy to change around . I'm also keen to get my hands on TN-2 and TN-3 crossover schematics . Do you have a website of the Taiwanese guy at all ? Thanks for your help
cheers
Hi !In my opinion your crossover is not good enough to appreciate the TD4001 on the azzura horn.
You should 3rd order on both HP and LP ans use a zobel network on your midbass unit, with a zobel, I reduced the response of the midbass unit up to 3dB above 1KHz !!!!!!!
And of course you should use a calculation for your true measured impedance, I really doubt that your LPAD change so much the impedance of the driver seen by the crossover !
Why not trying jmlc crossover topology, it makes the time alignment between bass and compresion easier and give you a nice impulse response when properly done !
please let me know if you find schematics of the crossover !
Didn't find the schematic but if you have any ideas just what it does maybe we can make an educated guess?? Here are the specs:
Type: 2-way dividing network. 1 x TN-2 network is required for each channel. Crossover frequency: 650HzMaximum input power: 300W. Impedance: 8 ohms. Level control: Built in: fixed at -10dB External: continuously variable. Rated loss: LF:0.4dB. Attenuation response: LF: -36dB/oct. HF: -12dB/oct. Outer dimensions (W x H x D): LF: 9-13/16 x 11-13/16 x 4 inches/250 x 300 x 102mm HF: 13 x 2-5/16 x 5-7/8 inches/330 x 59 x 150mm. Weight: LF: 6 lbs. 10 oz./3.0kg HF: 3 lbs. 15 oz/l.8kg. Accessories: Mounting screws (self-tapping screws M4 x 25) x 10, Washers x 10, Y-shaped terminals x 14, Hermetically sealing materials 1, Level controls 1.
Only $1,200.00:)
Russ
- http://www.pioneerelectronics.com/pio/pe/vgn/images/portal/cit_3442/37163TN-2.jpg (Open in New Window)
'Only $1,200.00:)'A BARGAIN ! I'll take two . LOL . Is that driftwood they use for mounting ? It's only TADs version of those generic Ratshack crossovers you know hehehe . I think I've got my head round these series notch filters and thankfully the parts won't cost $1200 . I have everything I need in stock including hefty oilers , non-magnetic R's , magnet wire and DIY teflon formers for the inductors . Hoping I can finally nail this problem and get my Tads to sound nice at last :) Either that or I'm going to swear alot and launch the things on Ebay . After that I suppose it's going to be time to dust off the Coral M100 or JBL 2420 and bolt the 1" - 1 15/16" flange adapters to the Azuras ;)
cheers
The one about measuring and freq. response? I don't know if you have gotten around to that yet. It might be helpful. Might be that the constant directivity boost you put in is too hot?? Maybe, if this is your first horn, (it is mine) we aren't used to the somewhat more upfront nature?? Running mine as both a 2-way and a 3-way I find I like a paper cone mid even though the horn is much cleaner. The paper has more warmth and just sounds "right" on stuff like piano and cello. But the horn is better on stuff like bells/vibes.One trick I employ sometimes, and it seems darn near perfect, is I drape some frabic over my horns. I used armchair covers! Very scientific, the right size, and happened to be in the listening area. I suspect when I measure I'll need to pad down the horn a tad more. Likely need to deaden the room too. All concrete and plaster. I have not fooled with deadening the horn and some guys talk about lining the inside with foam.
Anyhow, speakers are a bitch compared to tube stuff. Way more areas, like physcoacoustics, to need to know than I care to learn.
Russ
P.S. I'd blame darn near anything/everything before I blamed the TAD:) Now don't tell anyone over yonder, but my horn is actually smoother with a solid state amp than my previously sweet sounding tube amp! Seems an awful lot of guys here run the sonic T amps and I doubt you or I would consider such a thing.
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