Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 28th October 2017, 03:39 AM   #21
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Location: Portsmouth UK
Quote:
Originally Posted by irishiranian View Post
Good morning. I'm picking up this thread from quite a while ago! Hope you are all well.
I have a couple of questions.

I have just replaced the metal dome tdl tweeter with this soft dome.

AUDAX TW025A0 8 ohm 12 x 8 Tweeter, replaces IMF, Celef, Radford

I like the difference so far but I've had to put quite a big resistor after the cap that's feeding it.

Original value for the metal dome was 2.2. The new one is 10 ohm. It feels like it is at the right db now and was very overbearing with lesser values.

Onto my question!

Should I adjust any other xover components now that I have added such a change in resistance (in series)?

And will such a difference to the original value put a strain on the amp/ resistor/ anything else? (I have a fairly powerful amp. 2 rotel rb981s run as monoblocks -360 w per channel)

(System 7...I bought all of the components for the crossover redesign you kindly did. Haven't put them in yet...will I need to change any of their values now I have this new tweeter? I suspect so. Probably should have tried it before the new tweeter went in!! At least I still have the old ones and now have more options to tinker with!!)

Thanks
I quote that since we are turning the page.

The speaker is something like this:

Click the image to open in full size.

And the original crossover looks like this, we think, and it'll be positive polarity:

Click the image to open in full size.

I don't know what possessed you to change the metal tweeters to these? I wouldn't have.
AUDAX TW025A0 8 ohm 12 x 8 Tweeter, replaces IMF, Celef, Radford

There is a thing in simple first order capacitor filters called the RC constant. What it says is you sum all series resistance (including 6 ohms for the tweeter, we guess, so we are at 8.2R for the original) and note the 3.9uF capacitance. The product gives the response.

To get the same response with a different tweeter, with now 10R plus 6R =16R, we must take the capacitor down by about half. So know we want about 2.2uF capacitor. These values are hardly critical.

TBH, this speaker seems to have a terrible "Mickey Mouse" filter. I'm honestly surprised you like it.

I would be doing something more like this, which is not exactly what you have, but shows some general ideas which I will flesh out if you are interested.:

Click the image to open in full size.

In my experience, people often pick up these sort of polycone bass speakers sensing a bargain, because they are well-constructed. And the MTM setup is likeable for presence. And transmission line is an expensive and useful idea. But First order tweeter filters are woeful, IMO. Whyever did TDL skimp on this?

Which is why they quickly sell them again.
__________________
Best Regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 28th October 2017, 09:09 PM   #22
nerdorama is offline nerdorama  United States
diyAudio Member
 
Join Date: Aug 2005
Location: Seattle
Don't know if this will help, but I have a pair of TDL Super compact speakers and I think they use the same, or very similar drivers, but in a 2way bookshelf config. Here's the crossover which I traced from them. Accounting for the sensitivity difference of a single vs twin woofer the tweeter section is quite close to your proposed crossover. Sorry but the inductors weren't marked with values.
Attached Images
File Type: jpg TDL super compact xover schem.jpg (27.8 KB, 131 views)
File Type: jpg TDL Compact 11_24_09 007sm.jpg (187.4 KB, 510 views)

Last edited by nerdorama; 28th October 2017 at 09:11 PM.
  Reply With Quote
Old 29th October 2017, 03:06 AM   #23
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Location: Portsmouth UK
nerdorama, that's a useful post.

AFAIK, these are 16 ohm polycones, so my sim won't be exact on the bass. Mine optimised into a low bafflestep BW3 around 3kHz, negative polarity:

Click the image to open in full size.

Impedance correction must be right for the drivers, so 7.5R plus 39uF won't be right. Wonderful flat impedance! I'd guess your tweeter filter has a 0.4mH coil with 4.7R.
Attached Images
File Type: jpg TDL Super Compact Circuit.JPG (26.6 KB, 501 views)
File Type: jpg TDL Super Compact FR.JPG (47.6 KB, 503 views)
__________________
Best Regards from Steve in Portsmouth, UK.

Last edited by system7; 29th October 2017 at 03:10 AM.
  Reply With Quote
Old 29th October 2017, 03:48 AM   #24
nerdorama is offline nerdorama  United States
diyAudio Member
 
Join Date: Aug 2005
Location: Seattle
I know they sound very good with a tube amp.
  Reply With Quote
Old 4th November 2017, 10:08 PM   #25
irishiranian is offline irishiranian  United Kingdom
diyAudio Member
 
Join Date: Mar 2010
Always grateful for people's responses. Thank you. I'm looking forward to trying out your suggestions.

I got the soft dome tweeters to see how different They d sound to the metal dome standards.

Intruiged to know why you think I shouldn't have bothered? Always good to hear the opinion of people who are better informed, technically, then me.

My main aim is to squeeze a bit more midrange out of these speakers. I appreciate that it's slightly counter to what they naturally offer but I feel like the have a more balanced sound within...
  Reply With Quote
Old 9th November 2017, 09:31 AM   #26
ThetaII is offline ThetaII  United Kingdom
diyAudio Member
 
Join Date: May 2017
Hi IrishIranian, Steve and fellow posters
I have a pair of these for my main listening and have owned them for about 12 years. I wouldn't dream of replacing them unless I had to.
I found this post quite interesting as I have recently had an issue with one of the woofers (voice coil rubbing) and sought to replace it - haha, yeh good luck with that I hear you say. I attempted a repair on the woofer but unfortunately due to my inexperience, have compromised the movement of the spider - it works now without rubbing but I think its output is slighly lower than it should be. I found there aren't to many options for 16 Ohm drivers on the market but found some dual coil drivers that can be configured to 4,8 or 16 Ohms but not sure of their impact on the sound as yet.
I will also be looking at replacing the caps in the crossover (so thanks for the info on this) and in particular, the tweeter cap.
IrishIranian - If you decide to ditch any of the woofers or tweeters permenantly - PM me ..I'm sure we can come to some agreement
Cheers
  Reply With Quote
Old 9th November 2017, 01:44 PM   #27
ThetaII is offline ThetaII  United Kingdom
diyAudio Member
 
Join Date: May 2017
Just found the official schematic for the Studio 3's (unfortunately no values but shows a slightly more complex design than showing in IrishIranian's crossover, and more inline with Steve's thinking?)
tdl_electronics_studio_2_3-min-min.jpg - Google Drive
  Reply With Quote
Old 25th November 2017, 11:50 AM   #28
ThetaII is offline ThetaII  United Kingdom
diyAudio Member
 
Join Date: May 2017
For information - Studio 3 mk2 owners will find the crossover unit directly behind the binding posts on the rear of the speaker and not behind the lower bass/mid driver as shown in images on the net - which I guess are from version 1?
You will find 4 caps on the crossover - 2x 5uF caps, a 4uF cap and a 12uF cap. Please correct me if I am wrong or if you find Mk1's or MkIII's have a different setup.
  Reply With Quote
Old 26th November 2017, 07:32 PM   #29
ThetaII is offline ThetaII  United Kingdom
diyAudio Member
 
Join Date: May 2017
Photo of TDL Studio 3 mkII crossover: TDLS3crossover.jpg - Google Drive
As you can see in the photo, I have replaced the 12uF and 4uF caps ..going to replace the two 5uF caps as soon as the new caps arrive.

Last edited by ThetaII; 26th November 2017 at 07:34 PM.
  Reply With Quote
Old 30th November 2017, 05:48 PM   #30
ThetaII is offline ThetaII  United Kingdom
diyAudio Member
 
Join Date: May 2017
Please help. I'm trying to understand the concept of crossovers (I finally get the concept of high and low filters and even the point of (zobel?) bypass to aid the rolloff). As you can see from my posts above, I have dived in probably before I should have - thus proving a little knowledge can be a dangerous thing.
tdl_electronics_studio_2_3-min-min.jpg I believe C1 is 12uF, C2 & C3 are 5uF and C4 is 4uF. From info on the Studio 3's manual, the crossover point should be around 3KHz ...but from what I have learnt so far, a 5uF cap in series with a 4uF cap is going to result in a much higher crossover point. Could anyone please explain what I'm missing?
Just to add, I have changed all the old ALCAP's to Polyprop's (similar values) and having carried on reading, I understand that I'm going to need to add some resistors to redress the change in ESR. At the moment the Studio 3's sound like there is a slight hole somewhere between upper mids/lower treble.

Last edited by ThetaII; 30th November 2017 at 05:58 PM. Reason: Add diagram
  Reply With Quote

Reply


TDL Studio 3 crossover upgrade is better and yet worse as wellHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
TDL Studio 4 crossovers harwoodspark Multi-Way 3 20th March 2018 02:28 PM
TDL Studio 3 restoration droeftoeter Multi-Way 8 27th November 2017 09:28 AM
TDL Studio 3s irishiranian Multi-Way 3 24th September 2014 03:55 PM
TDL Studio 0.5- help needed! jonstar78 Multi-Way 0 30th December 2012 01:10 PM
TDL Studio 1 Paul Smith Multi-Way 3 22nd January 2005 11:05 AM


New To Site? Need Help?

All times are GMT. The time now is 11:31 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki