Another Troels Gravesen's DTQWT Project Build

[stu70]

Hey Brad, sent you a PM

 

Stu

[arpavieja78]

Hello Brad, how good you'll have company ....

What MKIII version you choose? With 2 drivers bass 10 inches or one of 12 inches ?

Regards

Rolando

Edited December 27, 2014 by arpavieja78

[stu70]

I went all the way...2x12":)

Not ideal for my current situation but I'm planning to knock down the house and rebuild in a few years time so hoping to give them the space they deserve.

My existing speakers are tolerant of corner placement, helps extend the bass horn but I think I'll have to damp the rear output on the 12" woofers a little on these in the meantime.

I use a sub just for the very lowest frequencies, helps the sound overall as well which has always struck me as odd but it works.

 

Stu

[Sierra]

Hi, I queried in the other dtqwt thread about whether the cad files were supplied.

if you could pm me the files it would be appreciated.

cheers

brad

 

Troels does not supply CAD files ... he supplies a fully dimensioned detailed drawing only ... the rest is up to the individual doing the build.

 

 

 

 

I went all the way...2x12"

Not ideal for my current situation but I'm planning to knock down the house and rebuild in a few years time so hoping to give them the space they deserve.

My existing speakers are tolerant of corner placement, helps extend the bass horn but I think I'll have to damp the rear output on the 12" woofers a little on these in the meantime.

I use a sub just for the very lowest frequencies, helps the sound overall as well which has always struck me as odd but it works.

 

Stu

 

2 x 12" in the MK III???  ... where is the option for that? 

 

For the MK III I've only seen reference to the single 12" (4 ohm impedance overall) or 2 x 10" version (6 ohm impedance overall)

[stu70]

Hi Sierra,

     you're right Troels only supplies his line drawings, I use CAD as part of my day job so it wasn't a great stretch to create a file for myself in AutoCAD, happy to send to whoever needs it.This forum won't let me upload a CAD file though for some reason. It is for the 212 model though, http://www.troelsgravesen.dk/DTQWT-12.htm

Looking forward to my mill worker coming back from his Christmas holidays:)

 

Stu

[Sierra]

Now how on earth did I miss that link??? 

 

Wow ... you have gone for the behemoth model ... looks like you and @@BioBrian will have a bit to talk about as he is the only one (AFAIK) in Australia to have built the 2 x 12" version of the MK II.

 

And we'll look forward to seeing pictures of your progress

 

Cheers,

 

Alan.

[arpavieja78]

Very nice Rolando!! You're going to love these speakers. I built a set of crossovers and completed the final assembly for a pair earlier this year. They sounded wonderful!

 

 

Thank you for your words, yes, I hope love these speakers!

 

Espero armar y amar estos parlantes, en ése orden ....

 

Ops, San Google does not translate the pun, not applied the Spanish to English ...

 

" Laughter is the spice of life "

[arpavieja78]

Oops.

Sorry for miss spelling your name.

 

Green wagon, friend from foreign lands (where is Wade?   ) Troels has also called me Ronaldo  in a recent letter !!!!

 

I do not want a third world war, my apologies, I thought it was a joke 

 

Again the Tower of Babel .......... :angry:

Edited December 28, 2014 by arpavieja78

[arpavieja78]

 

I don't know of anyone that has mounted the crossovers external.

Yes they are big crossovers but there is plenty of room inside the "horn" to accomodate them and there is no detriment to the sound so no real need for external mounting.

 

 

 

 

I think the same.

Although there is much place, I cut a little the board, do not know why, but here it is. The new bass / midrange is slightly larger, I'm calculating. Too finicky, I know, if you can not see 

 

 

Happy New Year to all !!!!

Edited December 29, 2014 by arpavieja78

[stu70]

Nice to see somebody's crossovers coming together.

I de-bagged all my parts, everything's there as per the order but as luck would have it the latest crossover diagram on Troel's website doesn't match the kit of parts I have:)

I ended up buying the top line kit, see attached, anybody else in the middle of assembling this one?

 

Stu

 

DTQWT - 212 - mkIII - 12 inch - Silver Z - SilverGold Z - Wax Coils - C-Coils - SEAS T35 Tweeter.pdf

[BioBrian]

What's different? The silver/gold ones are paralleled: 3 x 2.7uF to replace 8.2uF in tweeter part. Is there something else?

 

You didn't say whether you got a pen. I was going to order the kit just to get one, so don't let me down!

[stu70]

Hey Brian,

               sorry to let you down but there was no pen! I feel cheated:) I was assuming the 2.7's we're paralleled but got no info as to the circuit layout for this kit so I was hoping somebody had already put this one together.

For the bass crossover I have 10ohm grey resistor's instead of 15ohm shown on the diagram

There's no 100uf electrolytic cap as per the diagram but I do have two 100,00uf cross cap's to be used somewhere, sure it all makes sense with the correct diagram:)

 

[BioBrian]

No Stu, I think you're truly unique in lashing out on the whizz-bang version. Put me on the GTG list please...

 

The Cross Caps seem to always use a decimal point and 2 zeros after the uF value: 100.00uF is just 100uF, so that accounts for no electrolytic, which apparently many of us turn our noses up at.

 

It would seem that they did make an error with the 15 Ohm MOX resistors. The Mk lll single-woofer version has 4R7, so that's not the error, and my old original uses 15R too. Michael Jantzen is also a good communicator, so I'd suggest asking him what's happened. There might be time to get them posted before you finish your boxes, if we Aussies are anything to go by.

 

It seems that Jantzen put together all the options for kits: eg I've not seen Troels mentioning Royal Silver coils, but they have them in some kits for the very rich.

 

Are you going to rout your own driver holes? I read this morning that Troels found the new HMQs to be 0.3 mm larger diameter than the old ones, and had to go to great lengths to re-cut the holes in his Quattros.

 

At least you don't have to overlap them like in the old version, which would make fitting the WG virtually impossible after the holes are cut. (Just make sure you don't laminate the front baffle before you rout).

 

All the best with it; looking forward to hearing more.

Edited December 29, 2014 by BioBrian

[stu70]

Hey Brian,

               my first thought when I saw the list of kits was 'in for a penny in for a pound, lets head to the top'

I got an answer from Troel's and as you guessed the three 2.7uf caps are paralleled and take place of the 8.2 single cap.

The original electrolytic cap is replaced by the big cross cap. Need more ply real estate for this kit! I've attached a photo of the basic layout.

Just quizzing them on the resistors so hopefully I'll get an answer in the next day or so.

 

Re the cabinet, back in the day I used to have my own mill shop but having emigrated a bunch of years ago I gave all that up so I'm copping out a little and getting a millworker I know to CNC parts from my CAD file and I'll assemble at home.

 

How long did your speakers take to break in..or are they still warming up:)

 

[BioBrian]

Hi Stu,

 

My speakers are 2 years young now, and have stopped changing. I don't know if the 200 hours applied to mine, for a couple of reasons. One is that they got a really good workout at first, on a diet of big classical music, including lots of pipe organ. From the first tentative play, when the sound quality had me quite concerned, I'd say the first 6 or so hours saw the most improvement. They kept improving, and I'd guess the plateau was about 100-200 hours.

 

I've mentioned before that I think the cool climate here renders particularly the rear woofers a bit on the stiff side (like me on a winter's morning), and they loosen up with a bit of exercise. But that's hard to quantify because I think my Cyrus amps need even more warm-up: 6 hours of loud music to be at their peak.

 

Also there have been the changes: firstly the crossover change to the T35 filter, then the upgrade (yes, I'm now confident to call it that!) to the SEAS T35 tweeters. Both these changes took a little while to settle in. (I also noticed in my Tannoy project that crossover components need "burn-in" time).

 

I'll add again that these doubled 500 W "Pro Audio" speakers really do show a lot more of their colours with a bit of grunt behind them. I was using my 70 W stereo amp, but noticed a huge benefit from bi-amping with another 70+ Watts. A sustained very loud passage (in Mahler 4 slow movement, with bass drum, tympani etc) became much more clear and holographic again, using some of the Parasound A-21's 250 W. So good luck with your valve gear, but you might be tempted to try something more elephantine down the track.

 

I still have questions hanging, about the sensitivity of these drivers and their low bass response.

 

Regarding the CNC, can you tell us what materials you'll be using, and what hole diameters you are programming in? Some of us will be watching closely there, nursing sanded fingers. There doesn't seem to be an acknowledged "best" amount to leave for paint and comfortable fit. It would be good to hear the exact outer diameter of the HMQs, too, when you have a spare minute.

 

Lots of nice bits there - I can understand the wish for an external XO, but how will you route the wires? I wouldn't fancy having to drill through the baffles, especially with felt and stuff inside.

Edited December 30, 2014 by BioBrian

[BioBrian]

I  would like to address a mistake I made back in post 179, on p6. In that post I was talking about a nasty resonance in flute music which I thought might be to do with the speaker.

 

I got the octave wrong. The offending notes are in the 3rd (not 2nd) octave above Middle C, and the frequencies are from about 1400 - 1760 Hz, or F up to A.

 

These flute notes seem to crack up, sound shrill, flakey or unstable, and do so to various degrees, depending on both the recording, and the playback equipment.

 

I did say that I'd tried the offending recordings on other peoples' equipment (including some $20K gear) and could hear the same problem, so our dear DTQWTs are not the problem, and this is correct.

 

I'll place this scan, a hybrid from various sources, which I've put on my wall to keep me connected between the "numbers" and the "reality". Please post any improvements!

 

 

It happens more in (in fact for me defines) poorer recordings. This particular phenomenon sounds less bad through my new project using SEAS M15CH002 midrange drivers, which I think are just beautiful. But when I go back to the DTQWTs, they are just so amazing in the way they fill the space so effortlessly, there's no argument. They just sound "right".

 

I'd be interested in any other people's feedback about this phenomenon. Maybe it's my ears!

Edited December 30, 2014 by BioBrian

[Sierra]

@@BioBrian ... If only I was a musician and could actually understand half of the stuff you are refering to ... octave's ... middle C ... etc ... as much as I try and understand those things it just doesn't compute in this empty head of mine

I too have had the odd moment or two with some favorite tracks that have made me wonder "is that how it's supposed to sound"?

And then I have been lucky enough to hear the same track on much more expensive systems with a similar results ... confirming that the DTQWT as you say "just sound right".

The piano keyboard with the frequency's and other instrument frequencies is great ... and that I can understand

[BioBrian]

Sorry, I know we all come to this from different backgrounds. I just happened to get a music family in the hand-out.

 

An octave is just 8 notes. If you get a bunch of people singing "happy birthday", some of them will be singing the same notes! Joking aside, you'll find the women and the men singing the "same notes", but the men will be an octave or 2 lower. Middle C will sound most perfect with another C, A with another A, etc. Harmonies (chords) start when you add different notes.

 

Since physics came along, an octave is also a doubling of the frequency. If you take the bottom note A on the piano, then go up 8 notes to the next A, it goes from 27.5 Hz to 55. Another octave up is 110 Hz. 2 more octaves up gives you A 440 Hz, which is the noise you hear when an orchestra's tuning up.

 

I've found the table useful to understand what Troels is saying, eg when he adds an 8" woofer to make the ATS-4, he says it's to cover the 100-200 Hz range. That didn't mean anything until I looked and saw that 100-200 is the "octave" where the left hand of a pianist spends most of its career.

[Luc]

Sorry, I know we all come to this from different backgrounds. I just happened to get a music family in the hand-out.

 

An octave is just 8 notes. If you get a bunch of people singing "happy birthday", some of them will be singing the same notes! Joking aside, you'll find the women and the men singing the "same notes", but the men will be an octave or 2 lower. Middle C will sound most perfect with another C, A with another A, etc. Harmonies (chords) start when you add different notes.

 

Since physics came along, an octave is also a doubling of the frequency. If you take the bottom note A on the piano, then go up 8 notes to the next A, it goes from 27.5 Hz to 55. Another octave up is 110 Hz. 2 more octaves up gives you A 440 Hz, which is the noise you hear when an orchestra's tuning up.

 

I've found the table useful to understand what Troels is saying, eg when he adds an 8" woofer to make the ATS-4, he says it's to cover the 100-200 Hz range. That didn't mean anything until I looked and saw that 100-200 is the "octave" where the left hand of a pianist spends most of its career.

 

Feel free to expand upon this explanation anytime.  I'm like Sierra only much more so, there is thick>brick>wall>impenetrable...then me.

 

 

Great post!

[Sierra]

Feel free to expand upon this explanation anytime.  I'm like Sierra only much more so, there is thick>brick>wall>impenetrable...then me.

 

Great post!

Agree with Luc ... was a great post Brian ... thank you.

So an octave contains the notes "A,B,C,D,E,F,G,A" ... from A to A? ... but this is not an octave "C,D,E,F,G,A,B,C" even though it has 8 notes ... correct?

This music thing is tricky stuff ...

Perhaps ignorance is bliss in this case ... so much easier to sit back and just enjoy the music rather than try to figure it out

[Luc]

@@Sierra .  Alan do you know the album by the Moody Blues called Every Good Boy Deserves Favour ?

 

It's named after this

 

 

A  mnemonic for kids to learn when they are reading music, There are other ones but I'm to far into dotage to remember gitar lessons at Ashburton in the 60's

[BioBrian]

Thanks for the encouragement, gents. There could be lots more, but I do want to stay in relation to the DTQWTs in some way!

 

Alan, any 'interval' of 8 notes ending on the same note, eg F-F, C-C, A-A, is an octave. Pianos probably developed the way they did because it's an easy stretch to play "an octave" with your thumb and little finger. The Romantics liked to give show-off pianists (primarily themselves) runs of double octaves: eg 2 Ds in left hand and 2 Ds in the right. Very impressive amount of noise for less practice time than full chords. Our Western harmonic sense dictates that the intervals within the octave sound 'right' if you run (the backs of your fingers) from any C to the C above it. If you start a scale on any other note, you have to use one or more of the black keys. A-A has 3 black notes, so they didn't make it very logical.

 

By the way, in Happy Birthday, the 3rd time we sing those words, the interval between 'Happy' and 'Birthday' is an octave leap - the part a lot of us can't make and it dissolves into blissful chaos.

 

I've been naughty with a soldering iron today, hush hush... there are wires dangling out the bottom of my DTs...

 

It's been a full-on year; enjoy Auld Lang Syne, or at least the festivities preceding it, all.

[Sierra]

Thanks for the encouragement, gents. There could be lots more, but I do want to stay in relation to the DTQWTs in some way!

 

I've been naughty with a soldering iron today, hush hush... there are wires dangling out the bottom of my DTs...

Yep ... lets not get sidetracked too much ...

So ... spill the beans ... what are you up to with a soldering iron in one hand and wires dangling out from the botton of your DTQWT's in the other???

[arpavieja78]

Hi ! 

 

I have almost completed the treble bass-midrange-section. 

 

At last !!

 

It was a really fun job, but you need to think quite !!!

 

Regards !

 

 

 

 

 

 

[arpavieja78]

Bio Brian, thanks for the mini music class, excellent! Some things were known, others not, so I've learned something. What is not little!