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Multi-Way Conventional loudspeakers with crossovers

TDL Studio 3 crossover upgrade is better and yet worse as well
TDL Studio 3 crossover upgrade is better and yet worse as well
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Old 30th November 2017, 10:12 PM   #31
ThetaII is offline ThetaII  United Kingdom
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Default Correction

TDL_studio_3_values_small.jpg
Please for forgive my second error - I have assumed the original diagrams from IrishIranian were near correct and a simplified version of my Studio 3's. Please see the diagram above where I have written in (albeit a bit scruffy, sorry) the values of the components as I traced the circuitboard on my Studio 3 mkII's.

Please ignore my message about capacitance for the tweeter in the previous post as I can now see it has 4uF and 12uF series capacitors inline with the tweeter.

I don't totally understand why there is a 5uF across the woofers and a second 5uF in series with a 15 Ohms resistor across the woofers also - from what I've read on here, I would have expected cap (C1) in series with the 15 Ohm resistor to be of a slightly higher value?

Again, apologies for the previous confusion and wrongly made assumptions.
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Old 30th November 2017, 10:35 PM   #32
system7 is online now system7  United Kingdom
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OMG, THetaII, you are a nightmare!

Rubbing voicecoils on old 8" basses is most easily cured by rotating the driver 90 degress. Simple as that.
Click the image to open in full size.

That is a BW3, aka Butterworth 3rd order, it should do this with negative polarity on 8" bass:

Click the image to open in full size.

Click the image to open in full size.

I would never take a crossover apart without drawing the schematic and what values I can read, and noting what goes where. As it goes I have an inductance and capacitance measuring multimeter that makes this all a bit easier.

It's no good pulling stuff off the internet if you don't even know it's right for your model. Manufacturers frequently vary designs.

Doubling the drivers isn't such a big deal, but will modify the crossover substantially. You need to draw the schematic of what you have with as many values as you can read. Usually start with the live and earth tracks and the driver wiring. A photo would help, because I can guess a coil from looking at it to reasonable accuracy.
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Old 30th November 2017, 10:51 PM   #33
ThetaII is offline ThetaII  United Kingdom
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Hehe, Yes, you are right Steve - As I said, I stupidly assumed my crossover would be the same as IrishIranian's... but I'm learning, and now get the general gist of what is going on with this crossover. Although I'm not totally sure on how to correct the esr difference - I'm thinking of adding 1 Ohm next to C1 and a 2 Ohm resistor next to 12uF cap (C4) ...does that sound along the right lines to you Steve? ..and thanks for the tip on rubbing voice coils
IMG_20171130_223136.jpgIMG_20171130_215441.jpgInkedtdl_electronics_studio_3_values.jpg

Last edited by ThetaII; 30th November 2017 at 11:13 PM.
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Old 30th November 2017, 11:18 PM   #34
system7 is online now system7  United Kingdom
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Hold your fire on resistor changes. Some of them will make no difference at all. Some of those MKP caps are enormous, aren't they? People seem to forget this.

Are we sure about the schematic now? I usually flip the circuit board view to get the idea.

But I feel a headache coming on, or at least bedtime. May sim this when I have time. I'd guess the two 16 ohm woofers behave like one giant 8 ohm one electrically.

But does it sound OK, or worse, or better. In what way?
Attached Images
File Type: jpg TDL Studio 3 circuit.JPG (36.3 KB, 128 views)
File Type: jpg TDL Studio 3 Components.JPG (48.9 KB, 125 views)
File Type: jpg TDL Studio 3 Traces.JPG (112.3 KB, 10 views)
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Old 30th November 2017, 11:23 PM   #35
ThetaII is offline ThetaII  United Kingdom
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Thanks for your input Steve. I am fairly sure of the schematic ...now. There is more detail, but also as you and others have mentioned, changing to polyproylene caps has made the treble too loud, plus there appears to be a shortage of upper mids. Sleep well ..and any advice you can come up with is appreciated.

Last edited by ThetaII; 30th November 2017 at 11:46 PM.
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Old 1st December 2017, 06:22 AM   #36
system7 is online now system7  United Kingdom
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All I see needing doing here is taking the tweeter down a bit. Looks like a (red) 15R shunt will give you -3dB, a 22R shunt -2dB. -3db being half power. A 3W wirewound or ceramic will do fine wired between the tweeter output and earth. You might drill the circuit board with a fine drill at some convenient point to fit it in where there is room. Or use a bradawl if you have one. Don't make the holes too big though, that gets hard to solder.

No changes to the bass circuit required. The red 15R and 15uF is just a modelling device I used to correct the impedance for lower inductance woofers.

All works very well in fact. A very nice design after my own heart.

In hindsight, regular smallish Solen MKP 250V would have been easier, no? It is nice to get a good fit. More reliable.
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File Type: png TDL Studio 3 Adjust -3dB.PNG (8.2 KB, 26 views)
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Last edited by system7; 1st December 2017 at 06:29 AM.
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Old 1st December 2017, 07:02 PM   #37
ThetaII is offline ThetaII  United Kingdom
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Thanks Steve. Yes, hindsight is wonderful
A lack of knowledge and a silly assumption has made this a lot harder than it needed to be - but, on the other hand, it has forced me to learn the basic concepts of high, low, 2nd and 3rd orders and Zobel ..so I have at least enjoyed the experience.
Another order in at the HiFiCollective - Cheers
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Old 6th December 2017, 02:52 PM   #38
keilau is offline keilau  United States
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Quote:
Originally Posted by irishiranian View Post
Hiya,

I've just replaced all of the components in my TDL Studio 3s crossover.

I've gone for point to point soldering on the components without a pcb or board of any sort.

I've used the following components.

3.9uF 800Vdc Jantzen Superior Z-Cap (ON THE TREBLE)
10R Jantzen Superes 10W Resistor
2R2 Jantzen Superes 10W Resistor (2.2R)
12uF 450V Mundorf Mcap EVO Capacitor (ON THE BASS)

I've also got new inductors of the same value as the originals done by Gerry at Falcon who knows TDL speakers well.

The improvements in the treble is night and day. Much cleaner, more space better soundstage. The bass seems a tiny bit flabbier (not much in it though) but it's the midrange that seems to be worse. Not terrible but noticeably more muffled than before.

I've still got the original Xover in tact but before I start mixing an matching I thought I'd see what you all think could be the reason.

I'm letting them burn in/ run in to see if that makes a difference (I'm not trying to start a chat about that well trodden and controversial issue so let's pretend I never said it...just trying to eliminate all the possibilities!)

The only differences with the original values is the high pass cap which is a 3.9 rather than the original 4. I've also extended the wires a little as they were quite short and needed extra room to work. No more than 6cm with some decent van damme cable I had. I've used solder with a bit of silver in it and they have been running for a day or 2. Oh and the resistors are 10w instead of 5 but I don't believe that should make and difference.

Can anyone suggest why the midrange seems to have got worse?

Thanks
I was always a big fan of the TDL Studio 3 monitor, which was impossible to find in the US and shipping from UK is prohibitively expensive. A few years ago, I ran into some “Wharfedale M-138 Transmission Line Monitor” from Wharfedale in China (Pic 1). I bought them out of curiosity and found that they were the TDL knock-offs. They have the same aperiodic cabinet design (not TL) as the TDL (Pic 2) and a 2nd order crossover. The cabinet was very well built, but the drivers were very poor quality. I started a mod project.

wharfedale138_peerless-seas_small.jpg Wharfedale138cabinet.jpg

(1) I replaced the drivers with a pair of Peerless 850460 woofers and a Seas 22TAF/G ” Aluminuim/magnesium dome.

(2) I modified the cabinet by lining it with 3M 08840 Sound Deadening Pads and replaced the polyester wadding with long fiber wool.

(3) I modified the crossover to 3rd order and added a zobel network for the woofers. (Pic 3) I was able to keep the circuit board and bi-amp input panel. (Pic 4)
wharfedale138_peerless-seas_xover.JPG IMG_2391.jpg

Crossover mod was supported by Jeff Bayby’s PCD software which worked beautifully. The simulation result is shown in Pic 5. I kept the woofer bump to get a bass -6dB cut-off at 35 Hz. It worked exactly as expected. After I fine tuned the driver balance by ears, I made in-site measurement using Ivo Mateljan’s ARTA software. The dip at 450 Hz and the treble drop-off are room effect because I did not make the effort to measure outdoor. (Pic 6)
wharfedale138_peerless-seas_simulation.JPG wharfedale138_peerless-seas_measured.JPG

I have no intention of hijacking this thread. Take my post as an interesting footnote and stay on the topic of TDL. Thanks.

Last edited by keilau; 6th December 2017 at 03:06 PM.
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Old 20th December 2017, 08:23 AM   #39
ThetaII is offline ThetaII  United Kingdom
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Hi Keilau. As you said, it's all interesting. Are your speakers around 4 Ohms impedence?
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Old 20th December 2017, 09:06 AM   #40
bentoronto is offline bentoronto  Canada
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TDL Studio 3 crossover upgrade is better and yet worse as well
Quote:
Originally Posted by keilau View Post
...this thread. Take my post as an interesting footnote and stay on the topic of TDL. Thanks.
After 11 months of speculation, finally somebody posts data.

You can do a before-and-after comparison of changes using free/donation REW software (that runs on all OSs) and your laptop mic or a cheap mic...

... and an OP really really ought to do so first.

B.
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