Another Troels Gravesen's DTQWT Project Build

[Tube Nube]

Quick update -- I'm doing the final sanding with 180 and 220 grit sand papers, and I hope to start slapping on Varathane this afternoon, and install the drivers tomorrow. 

 

These sure are heavy suckers, but I think they're gonna look pretty nice, despite some minor flaws and differences between the two cabinets. 

[Sierra]

@@Tube Nube - Pics or it didn't happen Brenton

[Tube Nube]

Well Alan was "too right." I've been laid up the better part of 3 weeks with the worst cold of my life, and have desperately tried to continue chipping away, pathetically, through out the convalescence. All I have left to do is install the drivers. I think I can get it done tonight. Maybe even with pictures. 

 

One piece of advice for any prospective builder -- right off the bat, scrap the stoopid metric system. Spare yourself the eye strain, the use of a magnifier, or, like me, using a nail to count off ticks (for mm) on your ruler. If anyone hasn't seen an imperial ruler, the "ticks" for 1/8 and 1/16 are different lengths, so it's easy as pie (not Pi) to work with. 

 

I say do up a full sized drawing plan on a roll of paper, measuring it all out carefully with your metric measurements as given in the plans. THEN, go over your drawings with an imperial tape, and  write down all measurements again in inches and fractions of inches. BELIEVE me, when it comes to working with wood, this will be much easier. 

[BioBrian]

OK @TubeNube, so the big question from us over here: how much clearance did you leave around the drivers for painting?  - was it 7/128ths, or 43 thou? I can think of better ways to go blind!

 

Our local corner shop sells these neat little magnifying glasses, which I find quite good, if you don't mind bashing into everything in the workshop except the bit you're looking at. Outrageous that they went from $4 to $4.50 recently. I do a super-mod thing with heat and pliers, which stops them falling off my head when I look down.

 

@@Sierra's right about the pics - but don't worry, we believe you about the cold.

 

Your recuperation will give you a good excuse to sit & listen to them burning in, and escape from the terrifying ordeal of canned xmas carols 'out there'.

[Tube Nube]

Hmmm. I can't remember how much clearance I left, but I did drop the drivers in the holes for a test fit. Of course, that was all back in the summer. Now we're into winter, albeit, a nino warmed winter it is so far, with temps keeping around 0C so far. 

 

I hope I won't have to get out a hammer and chisel to make more room for the drivers tonight when I expect to pop them into place. 

 

2 1/2 more hours of work, then I'll be home to install the drivers. Stay tuned if . . . if that' works for you. I'll make a report back here in, say, 3.5 to 4 hours from now. 

[growler]

But Nube,

 

 The 0.5 mm marks are different from the 1 mm marks on my ruler.

 

G.

[Tube Nube]

Well, with apologies... i dont mean to be a tease. Probably all time estimates, when working on these, need to be multiplied by 3 or 4.

It's too dark for pictures, so I'll post those up tomorrow.

The speakers are done, in position, and playing! Halleluyahhhhh!

They are NICE! Without subwoofer assistance, I'm hearing some deep and downright punchy bass! Imaging seems pretty darn good. They have a smooth natural sound. So far I wouldnt say they are staggeringly better than my Saburos (single driver, double mouth horn type speaker). I think I now hear what others describe as horn speaker shoutiness--these (DT's) arent shouty like the Saburos are at times.

Visually, I'm really pleased with these. I may have another go at smoothing the globules of polyurethane here and there, maybe get another coat or two laid down to make em glisten, and get another few coats on the somewhat neglected back sides. Over all, I did a much better job finishing these than previous speakers. All plywood edges were "edged" with 6 pesky mm of birch hardwood, and it really gives the speakers a more finished look. The polyurethane reacted differently t the hardwood than the Baltic birch ply (darker), and the unexpected contrast looks really nice if I do say so myself.

 

Currently I set the optional resistor at 1 ohm . . .  looks like the intent is to play with it at either .5, 1 or 1.5 ohms, depending on whether you use one or both.  Is that right? Oh, hang on, I guess it's .5, .75 (both in parallel), or 1 ohm. I'd have to desolder one of them and put them in series to get 1.5 ohms. Do others think I should start out at a different value?

Edited December 8, 2015 by Tube Nube

[Tube Nube]

Pictures, at last. 

 

[Tube Nube]

[Tube Nube]

[Tube Nube]

[BioBrian]

Ah, then it's true after all. Congrats, and thanks for sharing your elation - quite contagious!

 

Your rear woofer looks a bit lonely, but I'd love to hear it. Probably super clean.

 

Painting's a very diffiucult art isn't it? - always a gamble and a struggle for me. The decisions you have to make are akin to assisting with birthing.

 

Neat feet - do they screw on underneath?

 

Enjoy - I'm sure they'll keep improving for a while.

[Tube Nube]

Hi Brian, 

 

Thanks for your comments. 

 

Boy it sure feels good to now be an official member of this club! I came home early to listen to these babies, and I'm having a great time of it. I've never had a speaker that could do bass on its own before, and these seem to really go down there. Later on, or on the weekend, I'll pull up Room EQ Wizard, and my SPL metred microphone, and see what the frequency response in my living room looks like -- and whether the subs will be an aid . . . you see, those rear firing woofers aren't as lonely as you first thought. In the first photo, to the right of the DT you can see one of my Rhythmic 12" sub woopers. There's another one behind the other speaker. 

 

I got those Subs on account of how my Saburos frequency response fell off at about 135 Hz. The Subs filled-in the missing bass, and a parametric equalizer did the job of taming modes, and smoothing out the picture below 120Hz. 

 

I expect the subs will make them selves useful again, here, with bringing down the ringing at room mode frequencies, but I'll be surprised if they need to do any bass lifting at all. 

 

Painting. Yech! I've been breathing polyurethane fumes for more than a week now. In  a few areas there are bumps from where it ran/streaked, or globbed up a bit. I gave up on cleaning brushes. Just got cheap foamy brushes and tossed 'em after a single use. 

 

 

I'll sure be delighted if these continue to open up as promised. I'd love it if vocals "came forward" a bit -- I'm noticing they are less so on quite a few recordings, compared to my other speakers. I'm sure I recall reading this is part of what gets noticeably better. 

[Tube Nube]

Oh yeah, the speaker feet. When I built my last pair, I some how mistakenly ordered enough of those for 3 pairs of speakers. Mercifully, they were quite cheap--about $6.00 per speaker. Or per pair of speakers. I forget. The points are brass, or a brass like metal substance, and they screw into a metal female thread that's housed in a plastic part that you can see that mounts to the speaker. Those are affixed to the bottom of the speakers with a single sturdy wood screw each. I think I got those from Parts Express, on line, but I can't find the part on their site any more. I just checked for you, in case you were interested. 

[Tube Nube]

It's only fitting that I enlist the help of Colin Hay's  solo project "Man at Work" to help in my listening tests. 

 

I feel no obligation to pay similar homage to Troels by listening to, what, ABBA, or some such noise.

 

;-)

 

Again, the bouncy bass of these bad boys is . . . brilliant. 

 

And they just effortlessly fill the whole house with music! 

Edited December 9, 2015 by Tube Nube

[BioBrian]

Polyurethane? Is that the 2-pot version, where you need acetone to clean the brushes? Haven't used that since my boat-building days. Lungs/brain cells are probably still recovering.

There's the single-pot one which cleans up in turps - Estapol?

And the polyurethane that I used, that cleans up with water - how's that for progress? But it gets less easy to use - I smell that 'compromise' word again.

 

Thanks for the feet info, but I'm OK with my home-made ones. Might be able to sell them to the museum one day, for mounting a vintage bulldozer or something.

 

Sounds like you'll be pretty happy not to have to use the subs. They're so slow, compared with the Deltalites, even if you get that bottom octave in better balance. Crossing around 40 Hz, and REW, might work for you.

 

Just reading your post about music for testing speakers - I'm often confused and dismayed that reviewers use old '70s or even worse recordings, and talk about the finer details of timbre and tonal balance, etc. But I did download the 24/192 Danish Vocal Ensemble's 'Libra' - good demo for vocal sound, but some of it is rather stomach-challenging musically! There might be better options.

 

Kalevi Aho's '3 Preludes for Organ' (from eClassical) have some interesting driver exercise, with the 3rd one soundng like the organist is demonstrating the Kama Sutra on the manuals - with an assistant lying on the pedals as well. Sorry to rabbit on about organ music again, but it's one of the satisfying attributes of these speakers.

[Tube Nube]

I believe you about the subs being "slow". I think it's that slowness I hold in my memory that makes the bass here sound bouncy, punchy . . .  It's quick. 

 

I have a friend who's really into subs, and helped me out a lot with mine, but I always had reservations about using them. Even though my old speakers needed the bass help, it seemed like the subs, in some ways, compromised the liveliness and naturalness of my old Saburos. 

[Tube Nube]

So it's Old Master's brand oil based polyurethane I used on these. 

 

Quite the stench. I see what you mean about brain cells. I was finishing them in the house, and was feeling pretty sick one night from a combination of the fumes and being under the weather. 

 

 

Hmmmm. Organ music. I should try some of that next! I have a few records on loan from my sub woofer amigo. 

Edited December 9, 2015 by Tube Nube

[BioBrian]

'Record', was that? Sorry, but I can't believe there's a stylus known to man, or even in his imagination, that would reproduce the frequency/loudness/amplitude of the hi-def files I'm referring to! If there is indeed, then I could understand that term 'dark side' a little better. I suddenly feel even more alone...

[Tube Nube]

Oh, I hope you're wrong about that, Brian. :-/    

 

My digital system is ok... It consists of a Squeezebox plus Monica DAC. 

 

But I've invested heavily in my vinyl system-- a Sondek with Linn as well as 3rd party upgrade parts. My cartridge is a Transfiguration, which was pretty highly recommended, but by no means top of the range. If the economy improves here, next time I need a cartridge replacement/upgrade, I might go to a dynavector in the $5k range . . . . 

 

I know digital system stats outstrip those of analog in various ways, but I'd be a bit surprised to learn (though not arguing) that those actually translate into superior sound . . . . 

[Tube Nube]

. . . I wonder if my digital system can make use of those hi def files you're tzlking about.... I know that Linn sells digital files in various definition levels. I wouldnt hesitate to download one for the higher definition cost, if I thought my system could use it. Not that that would be a substitute for a better digital system.

What are you using?

Edited December 9, 2015 by Tube Nube

[growler]

Congrats T.N.

 

They will get better and better with a few LPs, wavs, hours on them.

 

Pour yourself a glass of your fav beverage and enjoy.

 

G.

[Tube Nube]

Thanks Growler man!

I've been enjoying them most the night, and last night.

I posted up the pictures on a facebook group called audiophiles on a budget, or something like that. Never posted there before. Holy cow was I overwhelmed by the interest. I guess the name of Troels is no secret. There was a lot of interest, and quite a few good questions. And, Im almost embarrassed to say, many compliments.

[Tube Nube]

Yo, amigo de Brio',

Where'd ya go homey?

[BioBrian]

Um, moi? Sorry; re your question regarding my digital playback:

 

I'm still using the SPDIF DAC in my Cyrus 8xpd, (or 8dac), so haven't been up to complete immersion to the ultra-purist Tasso/Chanh/Tam approach, but have been moved sufficiently by (38+ pages of) it to build my own computer/server, over the last few weeks.

 

It consists of: HDPlex Linear power supply, giving 12V to the Asrock N3700 mini-ITX board, and 5V direct to a 512 GB Samsung 850 Pro SSD. The CPU is embedded: quad-core 1.6 GHz. 8 GB 1R RAM. Embedded graphics. Windows 10 latest build, and latest JRiver MC21 as player ('Office' not installed). Sound card is ASUS STX. This setup allows me to download, store, and play flac files up to 24-bit/192 kHz, and is quite an improvement of my older (silent) PC using a normal SMPS. It is completely silent, with no moving parts, and the biggest joy - it runs at around 33 W, including the power supply! Happy little homey for now.

 

Edit: the 12V doesn't go direct to the motherboard, but to a PicoPSU, which converts 12V DC to all the other voltages; this little card connects directly into the 24-pin ATX socket, so no huge bundle of pretty wires.

The low CPU current requirement (6 W TDP) is due to the 14 nm 'architecture' - the newer, tinier, cooler, more efficient bits of silicon.

Edited December 10, 2015 by BioBrian