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bostod
28-04-2011, 09:09
Hi there.
i have a pair of TDL RTL3's from ebay. cost me £120 and sound great. I have seen various reccomendations for tweaking the RTL2's but very little on their larger brothers.
for those who are unfamiliar the RTL3's use 2x 6" woofers in a large transmission line enclosure. this creates a huge sound stage and amazing bass.
the only tweaking I have done so far is to replace the tweeter with a Morel MDT 30. this gave a great improvement to the treble and reduces the Tinny sound significantly.
from what I have read, the crossover can be improved easily by changing the capacitors to audio grade, the internal wiring can be changed to better quality and the cabinets can be lined to improve the sound.
has anyone got any experience of tweaking these monsters.
my aim would be to tighten up the bass somewhat and hopefully bring some extra clarity to vocals and the more subtle parts to the music.
Am I asking to much of these speakers, they are so much fun I would not want to completely change their sonic character.

Come on Dave R, I know you have some experience of these, get that grey matter working

Techno Commander
28-04-2011, 11:52
I had a pair of RTL-1s which I upgraded. My list of mods was as follows-
Morel MDT33 tweeters
Rewire with mil spec silver plated LCOFC cable
Replace caps with boutique polypropylene alternatives
Line cabinet with damping pads and refit the wadding.

The mods made a ton of difference and improved speed, clarity and definition. They did well for a couple of years and were then sold (for a good price) to fund some JBLs.

DSJR
05-05-2011, 19:01
I can't argue with the above, but the fundamental issues in the crossover don't appear to have been addressed with the wholesale wiring and tweeter replacements above.

The comments below apply to the original bubble-veneer RTL3 mk1's, not the nicer looking mk2's, which had dire things done to them to make them sound more like the popular Acoustic Energy competition..... :mental:

TDL in many of their speakers over the years (and some IMF's before) "featured" a recessed midband and the RTL3 was a classic in this respect. If you look at the crossover network, there's a resistor across the bass coil (IIRC) and I think from memory that it's 15 Ohms. All but doubling this value to 25 - 30 Ohms approx lifts the midrange back to a flatter level, DRASTICALLY improves the loading on the amp (which is around 4 Ohms across the whole midband otherwise) and enables the rather exposed tweeter to be far better integrated, the small soft-dome helping with the roll-in at the crossover point (a larger dome would probably extend the tweeter down to far I think).

The electrolytic caps MUST be replaced with polyprop ones, but I wouldn't go too exotic here in all honesty, as the rest of the speaker isn't really worth it. Now, if you were talking of the "proper" TDL Studio 3's (from which the RTL4's were derived IIRC), then I'd suggest going all out for a major update/upgrade.

Hope this helps a bit. I knew the driver and basic "RTL-model" designer well and we had endless chats about these and other TDL models. The late John Wright did the "voicing" of these speakers, together with all the TDL and previous IMF models and I also understand from memory that John also designed the Goldring G800 cartridge and its derivatives way back in the late 60's..

bostod
29-07-2011, 18:11
I have finally got round to sorting these speakers out. I had a chat to Wilmslow audio who supplied all the components needed apart from the 27ohm resistor.
first I unsoldered the old capacitors and soldered on a Supersound 5.6 ufd and a 10 ufd capacitor. I replaced the 15ohm resistor with a 27 ohm one as reccomended by Dave R.
I lined the cabinets behind each driver with bitumen deadsheets to reduce any vibrations and changed the internal wiring of the woofers with black rhodium disco cable again from Wilmslow audio.I have currently left the original wiring to the tweeters as some recommend that silver plated copper wiring can make these sound too bright.
before putting the woofers back in I bought some wadding from Dunelm Mill. it looks and feels exactly like the original stuff.I placed the original stuffing in the first chamber rolled up loosely as recommended by Mike Snowdon in a popular tdl rtl 2 forum. I also put extra wadding folded over in the entire rear chamber.
when replacing the Woofers i used no nails as well as the screws to make sure they were secure.
then I plugged them all back in put the music on low and went to bed to let them burn in a little.
when I listened to them the next day I was blown away. the bass was still there but tamed significantly. the midrange was much more evident. to be honest I did not realise what people meant by midrange until I heard the change in these speakers. the Detail was night and day. I just sat there all day listening to my music collection, hearing more clarity And detail in each track. I finally fell asleep in the chair after some whisky and that is where I stayed all night
this upgrade is well worth the effort and even an amateur like me had great success with it.
one little question remains. on my TDL 3 crossover there is a wire soldered on where the small resistor is usually located on the TDL 2 crossover.
Is this correct and what would happen if I replaced this for say a 1.8 ohm resistor? like the TDL 2
i will post some pics of the crossover later for reference.

bostod
29-07-2011, 18:16
hopefully here are the photos
http://i1207.photobucket.com/albums/bb475/bostod/P1020397.jpg

http://i1207.photobucket.com/albums/bb475/bostod/P1020396.jpg

DSJR
29-07-2011, 21:00
If you add a resistor in series with the tweeter, it will reduce the tweeter level perhaps a tad too much, especially as you've increased the mid now (and made the RTL3 easier to drive in the process :)).

Why not just enjoy them as they are now, as doing what you've done may have really improved them. John Wright, who was very talented at designing and "voicing" his speakers (I understand he developed the Goldring G800 series of cartridges too;)), tended to reduce the midrange to emphasise bass extension, especially in his bigger models. This kind of balance can upset lovers of "fast" bass and a midrange which projects out of the box. Hopefully what you've done will be a great half-way point.

bostod
30-07-2011, 17:50
yes i am very pleased with the results. time to enjoy now :)
great tip changing that resistor.

DSJR
31-07-2011, 10:36
You can thank Clive Gibson (ex Elac, TDL and Musical Technology designer/engineer) for that. Before MF sadly disappeared (sold for peanuts to PMC), Clive built and repaired loads of 80's/90's TDL drive units the majority he designed as well (in John Wright's lifetime).

Glad you've givin 'em a new lease of life.

bostod
09-11-2011, 17:01
having listened to these speakers for quite a while now and given them time to burn in there continues to be a persistent problem. the tweeter still remains too bright. this is especially noticeable on the s and t's as well as the cymbals. how can I reduce this slightly without changing the overall sound of these speakers.

any ideas will be appreciated

Stratmangler
09-11-2011, 18:06
having listened to these speakers for quite a while now and given them time to burn in there continues to be a persistent problem. the tweeter still remains too bright. this is especially noticeable on the s and t's as well as the cymbals. how can I reduce this slightly without changing the overall sound of these speakers.

any ideas will be appreciated

http://www.rapidtoolsdirect.co.uk/images/uploaded/FAIAXE4.jpg

then a proper burn in

http://www.bythelights.com/wp-content/uploads/2007/10/_40989666_bonfire_parson_416.jpg

:eyebrows:

Reid Malenfant
09-11-2011, 18:54
:lolsign:

Chris, you are getting to be as bad as MartinT :eyebrows:

Stratmangler
09-11-2011, 23:17
Build a pair of these

http://www.audio-talk.co.uk/images/colin/P2010256.JPG

along with these

http://www.audio-talk.co.uk/colin/FRUGALST01.JPG

You could ask my mate Colin (aka Toppsy) to do the job for you if your woodworkng skills aren't up to much :)

PS - this is what I'm running myself, and I luv 'em.

zanash
10-11-2011, 11:40
back to your original question ..

tweeters too bright ..increase the resistance on the cross overs in steps till you tame them ..

as to the damping suggestions ...these are transmition lines ..the last thing you want to do is obstruct the sound wave as it passes along the folded column ..so unless the design is inadequate and the baffles are poor ..no damping should be required. If you damp the column the sound wave in the middle of the column will egrees at a different time to that at the edge ..cause all manner of unwanted sonic attributes ....
this not my opinion ..these ideas are laided out in a number of different books on the design of speakers ..and transmission lines inparticular .

DSJR
10-11-2011, 12:29
having listened to these speakers for quite a while now and given them time to burn in there continues to be a persistent problem. the tweeter still remains too bright. this is especially noticeable on the s and t's as well as the cymbals. how can I reduce this slightly without changing the overall sound of these speakers.

any ideas will be appreciated

OK, try putting in a half-ohm 5W resistor instead of the wire link and then try 0.75, 1.0 etc. up to around 1.5R in small increments. You could start with cheapo ceramic type resistors as fitted, and once you're happy with the value (I think 1.5 ohms will be far too much, but see how YOU feel).

Once you've padded the tweeter down to a comfortable level (the Supersound 5.6uF cap will actually INCREASE the tweeter output slightly due to lower resistance), you could then get a precision "boutique" 5W resistor to put in there.

One other thing, the 27R resistor could be chaged to one value higher 33R?. This will lift the mid a touch more and subjectively, you may hear this as slightly less treble, rather than an increase in midrange output - our/my ears are so easily fooled this way and that's why I don't trust 'em overmuch these days :)

Rare Bird
11-11-2011, 02:37
I love 'Supersounds' my fav polyprops :eyebrows:

http://i12.photobucket.com/albums/a222/LIVING-SIN/Caps.jpg


Dave (Bostod) i think an high quality resistor like the Mills 'MRA12' nay inductive Wire Wounds would be an idea, my fav power resistor :eyebrows: They do a massive range, 27R being available..

http://i12.photobucket.com/albums/a222/LIVING-SIN/Mills.jpg

:)

bostod
11-11-2011, 12:32
Thanks for all the advice guys. I am currently trying a monacor 1ohm resistor and it reduces the treble a little to much.
has anyone got any mills or other good resistors at 0.5 or 0.75 for sale. i wouldn't mind trying a 25 and 33 ohm resistor too for the mid.
if no one has any, can you direct me to a suitable place. Ebay doesn't have the ones i want

Ali Tait
11-11-2011, 16:54
Here ya go-

http://www.hificollective.co.uk/components/mills.html

A very good place to do business with, service is excellent.

bostod
15-11-2011, 18:34
took out the Monacor 27 ohm resistor and replaced this with a mills 30 ohm resistor for the midrange.took out the Monacor 1ohm resistor and replaced the wire for the tweeter.
this has increased the mid slightly and the harshness has been subdued somewhat. thanks for all the advice guys.I am going to leave these alone now and enjoy them. I think you can go on forever trying to tweak things. Very pleased with the results

bostod
16-11-2011, 23:09
back to your original question ..

as to the damping suggestions ...these are transmition lines ..the last thing you want to do is obstruct the sound wave as it passes along the folded column ..so unless the design is inadequate and the baffles are poor ..no damping should be required. If you damp the column the sound wave in the middle of the column will egrees at a different time to that at the edge ..cause all manner of unwanted sonic attributes ....
.

these are not true transmission lines Zanash. I think the studio versions were but these don't have the true transmission line interior.

Reid Malenfant
16-11-2011, 23:22
these are not true transmission lines Zanash. I think the studio versions were but these don't have the true transmission line interior.
No, they aren't... The clue is in the name 'RTL', reflex transmission line. As you point out the older "Studio" stuff were indeed the real Mc-Coy with huge enclosures compared to the RTLs & much deeper & cleaner bass reproduction as a consequence.

sparrow
05-04-2013, 16:47
Bought a pair of these monsters today...need to wire em up..and fire on some music but not just now as 'm too busy..Hope the effers work ok ..they came from cash convertors..

DSJR
05-04-2013, 16:54
John, were these the originals with bubble finish vinyl-wrap and full depth grilles (i.e. not the SE's)? If so, I think this thread has my recommendations for a flatter response, improved clarity and friendly amplifier loading in the midrange..

sparrow
07-04-2013, 15:46
Hooked them up on Friday night and although they sound ok..are a bit muddy at low volume. When you turn up the volume they are much better..nice treble and very good deep bass. I cant play em too loud most of the time so might use them when the neighbours are out and my wife. I bought as a package . Also included was a lovely Pioneer reciever and a sub woofer. £209 the lot..thought I did not bad. The reciever hasn't been tried out yet and it may be some time before it is...the reciever is a Pioneer VSX-1041i..about 8 years old and is in pristine condition..

DSJR
08-04-2013, 13:20
I think Pioneer's later receivers were very good as I recall...

John, seriously mate, if you have the original RTL3's, I promise you that if you change the resistor across the bass inductor for a higher value such as 30 or 33 ohms, the muddy bass at low volumes will seem to disappear, the sound will spring to life with no added colouration and the amp will thank you for having got an easier load given to it. this all started when a chap with an Audiolab 800C and P had the power amp running very hot and the 8000P thermal trip kept blowing after a good metal-session. Doing the mod increased apparent volume, the amp barely ran warm thereafter and he became a very happy bunny. It's a doddle to do if you can solder.

Firebottle
08-04-2013, 15:48
Fit the resistor as in the TDL 2 but try a 1 ohm.

Cheers, Alan

GeoffGreaves
03-07-2016, 16:03
Hi

I've purchased a pair of RTL3s "tweeters not working" to fix for fun and then listen to while I play around with the crossovers on my old DMS isobariks.
Only one tweeter is blown but both crossovers have seen better days, clearly overdriven with blackened PCB under the resistors (10 ohms, not 15) and bursting capacitors. The original TDL tweeters are Vifa D20TD-05-06; cheap, cheerful, and obsolete. They're also an uncommon 94mm diameter and 6 ohm. The bass/midrange speakers are too close together to fit a 100mm tweeter without modification to the tweeter as well as routing the cabinet but I have found that SEAS do 94mm tweeters and have ordered a couple of 19TFF1 H0737 units. As these are 8 ohms, same resonant frequency, but 1db less sensitive, I may have to fiddle with the crossover. As I've got one good TDL tweeter I'll take some measurements of original (with crossover caps replaced!) versus SEAS with both the 10 ohm and with 27 ohm resistors, as well as comment on how they sound to me.
Anyone else playing with a pair of these? They seem to be popping up on ebay all the time.

If these tweeters are a success I may replace the Vifas in a pair of RTL2s I have - might just drop in with the tweeter series resistor removed :)

Geoff

Smegger68
09-07-2016, 00:57
Back in the day I had a pair of the MkII RTL3's and simply replaced the tweeters with some Audax units from Maplins with no other mods. This lifted the performance quite significantly and saved them from the free ads. Ended up keeping them for about 8 years :D

GeoffGreaves
11-07-2016, 18:59
Job done. The 27 ohm resistor modification just caused the bass/mid-range units to tail off well before the tweeter took over causing a big dip in the response. The SEAS tweeter is much smoother and extended compared to the TDL Vifa with a marginal drop in db. However, the general frequency response was pretty messy - time to experiment with the crossover. Upping the value of the original 10 ohm resistor was out so I connected the bass/mid-range units in series and took it from there. I came up with the values shown below which up the DC resistance significantly - I haven't taken any impedance measurements and probably won't get around to it - so the speakers are now far more amp friendly. The 0,25mH choke is the original and the 3.3 mH is a Visaton 3698 (from CPC). All the components fit onto the original crossover pcbs. I reckon that the speakers are now as good as they'll get without cabinet modification; they may have extended bass but if you want to play AC/DC you really need something more solid but for music that won't upset the neighbours they're more than adequate.

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