Another Troels Gravesen's DTQWT Project Build

[arpavieja78]

3 hours ago, Tube Nube said:

 

Before going to the great trouble of building additional speaker units to reinforce the bass, does spousal approval factor have sufficient variability to allow some speaker movement?  

 

 

Brenton, the waf theme      is not altered because the boxes are already empty, they are the ones you see in the photos ...

 

[Tube Nube]

Hi Rolando, 

 

Now THOSE are a couple of Bad Hombres, to quote Donald Trump. i Hombres Malos ! 

 

I am using a free program called REW (Room EQ Wizard) in combination with a sound pressure level reading microphone by Galaxy Audio called the CM (Check Mate) 140, and a cheapo external sound card. With this, the software generates a sweep tone, played through the stereo, and the microphone, in the listening position, reads the SPL, and generates a frequency response graph. 

 

Using information from repeated sweeps, I adjust my sub woofers for volume, and the parametric equalizer to program nulls to up to -48 dB deep, and whatever frequency width I like, to tame room modes. 

 

Your post today has inspired me to re-tune things, since I’ve moved my speakers since last setting it up. 

 

I’ll do this now, then I’ll post graphs of my results, including the DTQWT-III alone, DTWQT + SubWoofers (un equalized), and then finally, Mains plus Subs all dialled in — at least to the limit of my frustration tolerance. I don’t expect to spend more than an hour doing this. 

 

Check back with you at 6:04 Mountain Time!

[Tube Nube]

Sorry I didn't follow up as promised. My laptop died in the middle. 

[arpavieja78]

1 hour ago, Tube Nube said:

 Sorry I didn't follow up as promised. My laptop died in the middle. 

 

 

Wow, it appears that Murphy¨s laws, : ..

"EVERY TIME YOU WANT TO DO SOMETHING FAST, BECAUSE YOU SEE IT EASY, IT WILL COMPLICATE YOU TO BE DIFFICULT"

It is not textual, it is the spirit of its laws, I just imagined it ....

 

Take your time, Brenton, thank you for the iinformation ! 

 

 

 

 

 

 

 

 

 

 

Edited February 27, 2017 by arpavieja78

[arpavieja78]

I FORGET TO GO UP SOME PHOTOS !!! , here are the assembly of the terminals. A dilemma presented to me, welding or using the terminals and nuts provided?
I chose the second option because I believe that too much temperature of the welder could loosen Teflon nipples, remember that the whole set was built by me, and honestly, I did not think about this detail.....

[Guest BobbyD]

On 27 February 2017 at 7:01 AM, arpavieja78 said:

 

Brenton, the waf theme      is not altered because the boxes are already empty, they are the ones you see in the photos ...

 

Hi Rolando,

I have been following your build with interest, very nice work.

Curious about your big woofer speakers, I am about to build some of my own using 15" drivers in 150 L boxes. How high frequency are you crossing them?

I was thinking of letting them go up to about 315 Hz.

 

Regards

 

[arpavieja78]

 

 

Hi

I'm glad you liked my work, thank you !

Do you want to do a sub or bass boost? Because exactly 315 hertz / sec?  Cutting that frequency is too high for a subwofer, you may have too much overlap with the bass of the other speakers. The usual thing is that they work by compensating for the frequencies that the other speakers of the system do not achieve.
Can you upload more data of your intentions? And the speaker? But please create a specific thread if it is not already here, remember that this thread is about DTQWTII and something of OT, but with this we would enter into a new topic.
You can also consult in a specific thread of subwofers from other forums or here,

 

 

I think it would be ideal....

 

 

Edited March 3, 2017 by arpavieja78

[Benen]

I'm so excited for everyone that has these running in their home!

Slightly off topic but still related.

I'm currently renovating my entire new but old run down home. I started the lounge room this week and removed the old in-wall combustion heater. Gyprock will go over the stud frame I've bolted to the wall and the TV will go above the cavity. All of the wires for speakers and TV will be hidden in the walls so should be nice and sleek! That's the next job.

I'm hoping to squeeze the amp and centre speaker into the cavity. Any opinions on whether this will work well? The cavity is 70cm wide and 50cm deep. I'd love to stick Troel's 8008 centre speaker in there one day to match the dtqwt's, it fits but I don't know how bad the acoustics would be affected being boxed in. Centre speakers are hard to locate suitably in a room!

I will also hunt for some suitable matched rear speakers to suspend from the ceiling once it is all finished. Maybe Troels will design some by then haha. So much work ahead!

[arpavieja78]

I think all the central speakers that Troels has designed have the tuning tube back, you'd have to leave some space there....

Good luck with the renovations !

[darth vader]

On 12/02/2017 at 6:54 AM, arpavieja78 said:

And very little, the bases with wheels and the front and back grids.

But I'm already enjoying the great sound of these speakers !

Realism, dynamics, very good intelligibility of the voices, there is no distortion even at high volumes (here we have to take into account valvular amplification), all instruments sound detailed and rich in harmonics. Very happy with the final result !!

And very little, the bases with wheels and the front and back grids.

But I'm already enjoying the great sound of these speakers!

Realism, dynamics, very good intelligibility of the voices, there is no distortion even at high volumes (here we have to take into account valvular amplification), all instruments sound detailed and rich in harmonics. Very happy with the final result !!

And very little, the bases with wheels and the front and back grids.

But I'm already enjoying the great sound of these speakers!

Realism, dynamics, very good intelligibility of the voices, there is no distortion even at high volumes (here we have to take into account valvular amplification), all instruments sound detailed and rich in harmonics. Very happy with the final result !!

Well done Ronaldo Congrats on completing them.

 

I'm sure you will like them even more after they loosen up a bit. I havn't found any type of music that they struggle with, they are a good fun speaker

Edited April 4, 2017 by darth vader

[BioBrian]

On 3/13/2017 at 10:21 PM, Benen said:

Slightly off topic but still related.

I'm currently renovating my entire new but old run down home. I started the lounge room this week and removed the old in-wall combustion heater. Gyprock will go over the stud frame I've bolted to the wall and the TV will go above the cavity. All of the wires for speakers and TV will be hidden in the walls so should be nice and sleek! That's the next job.

I'm hoping to squeeze the amp and centre speaker into the cavity. Any opinions on whether this will work well? The cavity is 70cm wide and 50cm deep. I'd love to stick Troel's 8008 centre speaker in there one day to match the dtqwt's, it fits but I don't know how bad the acoustics would be affected being boxed in. Centre speakers are hard to locate suitably in a room!

I will also hunt for some suitable matched rear speakers to suspend from the ceiling once it is all finished. Maybe Troels will design some by then haha. So much work ahead!

 

Maybe you're right, and this Centre Speaker to match DTQWTs topic should start a new thread - I bet there'd be some interesting content appearing.

 

Some thoughts:

 

It'd be bad to put a speaker in that hole - bass would be a mess, especially if it's a vented box. Better to stuff it with insulation, cover with membrane and/or slats, and have it as a bass trap.

 

The centre speaker drivers need to be at the same height as the DTQWT drivers.

 

The vent (as I've done, with success) can be built into the side of the box, instead of the rear. Maybe an email about that to Troels could be valuable.

 

If it needs to be close to the wall, maybe consider a sealed box, or try aperiodic tuning (stuffing things in vent) to reduce room gain.

 

My experience with HT is that the centre speaker gets a HUGE amount of bass, if set as "large". Setting the centre speaker as "small" will roll off the bottom end, but you can keep a vented box, to preserve the designed box tuning for the frequencies that make it through the High Pass (Low Cut) filter in the receiver.

 

The JA-8008 Centre speaker would of course be a great match to the DTQWTs, in that it has the right sensitivity, but also that it has a mid-driver, which I'm sure would enhance the intelligibility of speech in movies.

 

I personally would prefer to try the Audio Technology 3W Classic, as I'm not convinced about the wisdom of 2 side-by-side drivers, when for all but solo listening, the listeners will hear them out of phase with each other. Its 92dB is usefully close to the sensitivity of the DTQWTs, and would give super quality mid-range (as well as everything else), without overpowering bass due to room gain. They'd make awesome surround speakers too!

 

Sorry this is such a late reply, but I've been crippled with a back issue and surgery. Let us know if you've made progress matching the DTQWTs in a surround system.

[darth vader]

@BioBrian I've transplanted my Troels into my HT system and the are delicious. With proper set up they could be even better.

 

@Benen I'd love to try the 8008 as a centre, and I agree, maybe Troels may may design some surrounds that can match.

 

I guess until the day I watch more movies than listen to 2 track, mine are on 2 track duty.

 

As far as subs go, I'd love to own an Osbourne sub. Not that the DTQWT's dont go down low enough, but until Troels goes there,  Gregs subs seem a great match

[Benen]

Well I've started building Troels' Discovery 18W speakers to use as rear HT speakers. I thought something smaller and something that will receive less attention would be a great place to start!

I've built the boxes from MDF using a track saw and router. 

It mostly went very well, however the track saw at its 45° setting looks like it was closer to 43 or 44 degrees as there is a ~1mm gap between the joins! Hopefully it will shrink when clamping to glue. 

I'm hoping that I can fill them with a putty of MDF and PVA and then prime and finish with many layers of paint and sanding. 

Alternatively veneer can cover the entire box!

I've ordered the kit from Jantzen for around $700aud so a much smaller investment than the DTQWT speakers and a much simpler build for me to learn!

If things go well I will be very keen to start the DTQWT speakers very soon after.

 

I am struggling with the routing of small holes! I have a Festool 1400 router and have modified the rails to use as a circle gutting jig but it will only go so small. 

How are you cutting such tiny holes with the router? I was going to make a jig like what Troels uses, however it still looks like the wing nut will get in the way of the router base when you want to make small holes for tweeters or holes in the bracing?

Edited June 10, 2017 by Benen

[arpavieja78]

 

 

 

 

 

 

612/5000

 

Hello everyone ! 

I would like to extend my greetings and thanks to all those who have kindly shared my contributions on this construction .

I have not yet finished the protection grids and bases with wheels to allow an easy transfer inside the living room.

http://www.troelsgravesen.dk/DTQWT-Rolando.htm

I am currently trying to extend the response in the first two octaves, and the only way to do it correctly is to add a subwoofer

But I need to clarify something, I will do it in the corresponding thread of subwofers

Greetings to the whole community, especially Sierra, and Bio Brian, I hope your spine is better. 

[BioBrian]

Hi Rolando, and thanks for your kindness.

 

I read about your experiments from Troels' website - very interesting, and in character!

 

I am hoping that you stay stereo, and use "hifi" woofers, if anything, to boost the DTQWTs' bass. If you use a turntable, I would not expect very nice noises to be the fruit of your endeavours .

 

I often wonder what would happen if Troels had gone ahead with the even larger DTQWTs, with twin 15" woofers and longer horn.

 

I had the idea of adding another ~400mm to the base of mine, extending the horn (down to 24 Hz) and raising the drivers more to ear height, but it's a lot of work to find out.

 

I found that using a 2-wheeled trolley is very easy and cheap - much better than wheels under your speakers. (Fix some felt padding, and come in from the side).

 

[arpavieja78]

On 11/10/2017 at 5:21 AM, BioBrian said:

 

...............I read about your experiments from Troels' website - very interesting, and in character ! ....

 

Yes, I wrote to Troels about my experiment and he advised me not to leave the Emimence 2510 II superior by acting as a passive radiator. It changes the performance of the horn, it is better to plug this hole directly to keep the horn flat without that modification.
But I have not. My plans are to use the high level output, (here you can see why I insist on that, the low level signal runs too many circuits and here I am minimalist )
"the shorter the better" (does not apply to female tastes, I suppose    ) See last post.

 

Yes, I keep in stereo and the turntable I use less every time, for the same reasons that you mention. I hate clicks and pops, and I think the vinyl revival is a return to prehistory of audio. I'm going for an Oppo Sonic for a good streaming service, I'm pretty happy with Tidal, but taking the signal from the headphone output of a laptop is heresy. We will see how much improvement. It is an important investment. I read something about what happens in your country, not Oppo Sonica ? Why ?
With respect to the twofers of 15, well, I think (because I've heard very spectacular things) that
the acoustic pressure achieved with large twofers is a feeling of presence and space that gives another dimension to listening.
I took a look at the papers that recommended me in this link.
Basically, they are patents in the style of the beasts of JL, USA. Tremendos magnets, tremendous xmax, tremendous amplifiers, all superlative and oversized. (Again I imagine a smile on some ladies if they read this   )

 

 

https://www.google.com/patents/US6418231

 

Look at those pictures !!

It's not what I'm looking for. I have plenty of space to go for the classic, besides, I'm a classic, to each one what corresponds, let the youth turn with their cars driven to pure sound resounding bass.
If you do your experiment without altering the construction, welcome, but, could it work? , maybe yes, maybe I do not see anything proven if you let me insist on the advice.
It would have to "simulate" with software ..... Neurons have limited life, we must take care of them. I prefer to play chess on the internet to keep them active and not learn new things. I downloaded hornresp, and I left it in half an hour. Scholars can teach me a lot about this, why insist? I want to sit at the table and enjoy lunch, period.

The discovery is spectacular !  I will consult with the witch, but even though she is tolerant, I believe that there will be no possibilities here.

PS: Witch is a very used nickname here for our beloved wives ....

I regret my English, this time there may be horrors, because I will not correct anything, it goes directly without previous analysis of the text.

Edited October 12, 2017 by arpavieja78

[Ooogh]

Gentlemen.

Let me just say I am simply amazed at what you have all achieved. The level of craftsmanship and cabinetry work on display within these pages is just incredible. If I were to purchase a pair mega dollar factory built speakers with the quality of finish  seen here I would be a happy camper indeed.

 

I am presently weighing up my options in terms of high efficiency speakers and I am wondering if per chance anyone is sporting a pair in Adelaide I would be able to hear? Failing that a road trip to Melbourne may be a possibility. Obviously with such a substantial investment listening to a pair prior to taking the plunge is advisable to be sure they suit may particular requirements.

 

I am also interested to know if a pair have ever turned up second hand? If not that would go a long way to illustrating just how good he end product must be.

 

This forum should be renamed DIB. Do It Better. (Than factory!)

 

Cheers

[arpavieja78]

Hi BioBrian, I have noticed that you may not correctly interpret your phrase "I hope you stay in stereo". You referred exclusively to subwoofers, and the answer in my particular case is NO!

Buy a single Dayton SPA250 plate amplifier, and join the stereo inputs into a single monophonic output.

There will be no update of this section in stereo, honestly, I do not think it's worth the extra expense. The two JBLvintage bass reflector cabinets that I use - something that surprised me from the start - come lower than DTQWTII.

The experimentation I did has come to an end, the result achieved is all that I needed. and no more boxes in my living room. The subwoofers are omnipresent and you can not perceive any directionality of them. Again, I refer only to the first two octaves, below 40 hz. At one time I am very excited to make a folded horn with a single 18-inch subwoofer, for professional use, for PA!
But it was discarded for several reasons that have no specific relationship with the audio. WAF among others. Maybe one day I will. " Never say Never "

The recommendations on the choice of subwofers are divided (as always) between those who prefer a single large SD speaker, and large box (15.18 or 21 inches) and those who defend two speakers and smaller boxes (typically 12 inches) because well placed in the room more easily achieve the feeling of NO directionality.
Again, is there a perception of bass in stereo?
I think I have already uploaded this link, but again I will use it to try to be more explicit.

While I'm halfway there (two 14-inch subwofers, but in monophonic connection) I'm really happy with the result in my listening conditions (room, cabinets location, phase tuning, etc.)
In the latter case it seems strange but they are in phase although the sub face the DTQWT ..... but what happens is that the rear speakers radiate from behind on the front wall. At the end and after several tests and a few drinks, I remain like this .... I would have to repeat everything while sober !!!.

Read about the thread of Oppo Sonica in a few days, they have discontinued it but now I do not have time to curse !!!

 

https://kenrockwell.com/audio/stereo-subwoofers.htm

 

" This all applies to true stereo recordings, which means most classical recordings. With popular music, there is rarely a concert hall involved, and having stereo bass is mostly a matter of where the bass effects are panned."

[arpavieja78]

On 20/04/2018 at 4:52 AM, Ooogh said:

...............

 

Edited April 28, 2018 by arpavieja78
18/5000 involuntary mistake

[arpavieja78]

On 20/04/2018 at 4:52 AM, Ooogh said:

Gentlemen.

Let me just say I am simply amazed at what you have all achieved. The level of craftsmanship and cabinetry work on display within these pages is just incredible. If I were to purchase a pair mega dollar factory built speakers with the quality of finish  seen here I would be a happy camper indeed.

 

I am presently weighing up my options in terms of high efficiency speakers and I am wondering if per chance anyone is sporting a pair in Adelaide I would be able to hear? Failing that a road trip to Melbourne may be a possibility. Obviously with such a substantial investment listening to a pair prior to taking the plunge is advisable to be sure they suit may particular requirements.

 

I am also interested to know if a pair have ever turned up second hand? If not that would go a long way to illustrating just how good he end product must be.

 

This forum should be renamed DIB. Do It Better. (Than factory!)

 

Cheers

thank you very much for the part that concerns me!

A while ago there was a young man who complained about the lack of sub-bass construction MKII and sold them. Bad decision so you can deduct from my previous post .... But if you go for the MKIII version, with a single 12-inch driver, I do not think you'll be disappointed. Even maybe you do not need subwofer, - it depends a lot on your musical tastes - but I really can not comment with authority because I have not listened to them.
But my opinion is that if you are looking for high efficiency, MKIII will surely give it to you.
Based on MKII, I have found a very extended range of frequency response, (with the exception of subwoofer frequencies, some will call it fast, well, I do not share that) without colorations, excellent dynamic range and intelligibility in voices, this last He has left me very gratified. The middle area is excellent. Invest in the cross over as much as you can.
I use valves, (PP, KT-88 and EL-34) if you use SS you may have many other Troels designs that may interest you.

Greetings and keep us informed of your decision .....

Edited April 28, 2018 by arpavieja78

[BioBrian]

5 hours ago, arpavieja78 said:

the answer in my particular case is NO!

.....

While I'm halfway there (two 14-inch subwofers, but in monophonic connection)......

Hi Rolando, good to hear from you again. Your sense of humour is good medicine, as always!

 

Thanks for the link - I enjoyed reading again about stereo subs, and this does confirm what I hear with my new speaker system.

 

Yesterday I happened to be playing with the DTQWT-12s, and took one of the bass drivers out while playing a very low (23 Hz) sine-wave tone. They make a certain sound from the outside of the box, but when I put my head inside (with one driver still in place, the other in my hands), the sound was a lovely soft, ultra-low hum, with no apparent harmonics, and of course no room noises. Quite different. It made me appreciate just what the large horn is doing with these woofers.

 

When I look at the datasheets for the 12" and 10" versions of this Eminence Deltalite driver, the curves are more or less the same, rolling off quite dramatically below 100 Hz. This confirms for me what I may not have said clearly in my previous posts - that the size of the Deltalite doesn't make much difference to bass extension. It's the horn length that makes the big difference. The following graph shows the 2512 (12") FR response, and we can expect that the horn boosts the lower frequencies. Otherwise, surely it is a joke that we can call this a "high-sensitivity driver" - OK, 97 dB above 120 Hz, but this is not what we are most interested in! (The Deltalite 2510 (10") driver curve looks very similar, but about 2 dB less output).

 

 

Having said that, I still think what Troels arrived at, with the JA8008 and wave-guided tweeter, is a bit of a miracle - very satisfying to listen to from all angles, distances, and whether loud or soft. That the JA does 2 "decades" (20-200-2000 Hz) so well is quite an achievement.

 

Edited April 29, 2018 by BioBrian
Giving Mr Hertz a well-deserved capital letter, etc

[arpavieja78]

16 hours ago, BioBrian said:

Hi Rolando, good to hear from you again. Your sense of humour is good medicine, as always!

 

 

Hello brian, I'm glad to hear from you too. !

Thanks for your words, yes, I believe that a touch of humor is always good, it helps to live more relaxed.

What is your last construction, can you pass me a link?
It's a horn so you account ..

[arpavieja78]

In this regard, I will tell you my opinion, purely as an amateur and personal.

The wavelength of the frequencies are related to two aspects. Radiation surface and frequency emitted by the speaker.
When our goal is to reproduce the lowest frequencies, the method to use is not exclusive to the horns, although I totally share with you that they have their particular sound, a charm and naturalness that a modern commercial subwoofer does not achieve .....

Then, my thoughts and doubts ...

If those modern subwofers with small boxes, (sealed or reflex), and technically designed speakers with specific objectives of reproduction of very low frequencies, they manage to reproduce (and in what way, hopefully it could be the same in our acoustic boxes!) The low frequencies, they do it with amplifiers of tremendous power that compensate for the natural amplification of a speaker. But the FS of the driver is important there, perhaps much more than in a system of natural amplification by horns!

"A loudspeaker without an enclosure does a very poor job of producing sounds whose wavelengths are longer than the diameter of the loudspeaker. For an 8-inch speaker, diameter of speaker equals wavelength at about 1700 Hz. Even for a 16-inch speaker, the diameter equals the wavelength at 850 Hz. loudspeaker without an enclosure does a very poor job of producing sounds whose wavelengths are longer than the diameter of the loudspeaker. For an 8-inch speaker, diameter of speaker equals wavelength at about 1700 Hz. for a 16-inch speaker, the diameter equals the wavelength at 850 Hz ".

[arpavieja78]

The link :

 

http://hyperphysics.phy-astr.gsu.edu/hbase/Audio/spk2.html

[arpavieja78]

 

 

 

 

 

666/5000

 

So, I also think about the excellent reproduction of frequencies of a good headset, you can hear 20/30 hertz absolutely natural and deep, hopefully my boxes (and I think the vast majority of those that exist) would have the sound of a model of high-end Sennheisser, for giving just one example of so many excellent brands.

And what is the radiant surface of the diaphragm of an earphone?
  Obviously influences the immediacy of the human auditory system with the same ... but I miss the details ....
I recognize that I have difficulty understanding this apparent contradiction ....

Maybe some scholar here can clarify this.