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Another Troels Gravesen's DTQWT Project Build


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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 :wub:   ) 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   :lol:)

 

 

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

 

Look at those pictures !!:ohmy:


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 ! :lol: 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 by arpavieja78
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And so we come to the final installment ...       Spacers on the mounting plate ready for the base.       Aligning the holes on the base with the holes in the spacers and screwing the hex

Finally wired them all up today and running them in now. looking forward to getting them home to my full system, after a few weeks here at the workshop.   Still not sure on what to de withe

Hey @BioBrian ... Yes mate they are still going well. If I really like something I tend to hang onto it ... and these for me are a keeper.   Both the timbers have darkened over time ...

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

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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."

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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 by arpavieja78
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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).

 

949473586_2512FRcurve.JPG.2bd656c70aa263871bfdc9c2c48e84c8.JPG

 

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 by BioBrian
Giving Mr Hertz a well-deserved capital letter, etc
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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 ..

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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 ".

airimp.gif

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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.
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17 hours ago, BioBrian said:

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).

 

949473586_2512FRcurve.JPG.2bd656c70aa263871bfdc9c2c48e84c8.JPG

 

 

 

 
 
 
 
 
1096/5000
 
Well, this is exactly what I think will help me explain my point.

This speaker is excellent, but look at the Fusion construction of Troels and the speaker that I use, and you will see in the specs that it is much superior to this Eminence.

Simply because the Deltalite II models, whether 2510 or 2512, are not subwofers.

From the data sheet 2512 it is clearly observed ...

100 hertz to 95 db SPL
65 hertz to 90
50 hertz to 85
30 hertz to 76 ...

If we take into account that each drop of - 3 db of SPL we must compensate it by doubling the power in watts, we clearly see that "the part that interests us" is very poor for use as a subwofer.

From 95 db in 100 hertz to 76 db in 30 hertz (assuming 1 watt / 1 meter) we have that for subwoofer we have consumed all the power of a push pull valve (average 40 watts) and for a SET the 8 watts (average also ) not enough .....

Hence the use of dedicated amplification for subwoofer frequencies.

Dayton, Hypex, etc, etc.
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238/5000
 
Por esa razón, creo que lo mejor de los mundos lo disfrutan aquellos que pueden escuchar algo así, al aire libre.

No se preocupe por fases o reverberaciones, como el sonido de un trueno, todo lo que sale de allí, se disipará de forma nativa .....: frenético::PAG;)
Hurt that boy, I should read some photography before taking his cell phone .......
 
 

Al aire libre.jpg

Edited by arpavieja78
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4 hours ago, arpavieja78 said:
Por esa razón, creo que lo mejor de los mundos lo disfrutan aquellos que pueden escuchar algo así, al aire libre.

No se preocupe por fases o reverberaciones, como el sonido de un trueno, todo lo que sale de allí, se disipará de forma nativa .....: frenético::PAG;)

 

"For that reason, I think that the best of the worlds is enjoyed by those who can hear something like that, in the open air. Do not worry about phases or reverberations, like the sound of thunder, everything that comes out of there, will dissipate in a native way"

 

Brian

 

Edited by BioBrian
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I'm not sure about the BMS 12N630 (in Troels' "Fusion") being a subwoofer - it has lower Fs, but looks to me the same type of driver as the Deltalite. Still with 9 dB drop  in the octave from 100 Hz down to 50 Hz. 'Dry, deep and punchy', but 500 W of Hypex and some DSP should get it moving (Fusion-BAD)!

 

My present speaker (same woofer as nearly 3 years ago, not much new to see!) uses SBA 15” SB42FHC75-6, which has Fs of 23 Hz, and only droops 5 dB from 100 to 26 Hz (2 octaves), at least on the datasheet. My measurements show a difference, but in my 240 litre vented enclosures the combination of direct and vent measurements come fairly close. Bass extension is much better, maybe at the expense of some ultra-clarity. The concept:

 

Large size

Low power requirement

No Equalization

Low bass

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8 hours ago, arpavieja78 said:

"A loudspeaker without an enclosure does a very poor job of producing sounds whose wavelengths are longer than the diameter of the loudspeaker."

It introduces another element to the high pass response of 6dB/octave.    This means more excursion is required to get the equivalent SPL to a closed box.    However because there is no box contributing to the mechanical system, this doesn't mean that there is more power required.

 

Due to the additional slope in the high pass response, that is present through out the region that we want to use the driver (and due to the peak in the top of its working range) ....  it DOES mean that a much more complex filter is needed.   The speaker is much more difficult to design.

 

On 29/04/2018 at 10:08 AM, BioBrian said:

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! 

It is quite a sensitive driver ... but rolloff in the lower octaves, as most do.

 

A quick and very dirty simulation of the box, shows boost down to ~40Hz with that "horn".

 

"horn"? ....  Semantics.    If you squint at this box, is it a "bass reflex" speaker? ....  Does that mean all bass reflex speakers are "horns"? ..... Is this really a horn?    (Does, it matter?  No .... but it's an interesting thing to consider).     It sounds cool to call it a horn, so people do.

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3 hours ago, davewantsmoore said:

"horn"? ....  Semantics.    If you squint at this box, is it a "bass reflex" speaker? ....  Does that mean all bass reflex speakers are "horns"? ..... Is this really a horn?    (Does, it matter?  No .... but it's an interesting thing to consider).     It sounds cool to call it a horn, so people do.

An upskirt squint would dispel any thought of similarity with a bass reflex design - if we are indeed talking about the DTQWT. I'd half-cheekily say that it has more in common with a waveguide.

 

Troels calls it a tapered tube; it is different from what most of us know as a horn. It's non-exponential, and the drivers enter at between a quarter and a third of the tube's length - hang on, a tube's not tapered anyway, and god forbid, these tubes don't glow in the dark, but they taper off tube-like - looking like lexical semantics. Good thing it works as intended, whatever.

 

The latest Mk lll version has a token change of angle toward the tube mouth - more horn-like, with some imagination.

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37 minutes ago, BioBrian said:

An upskirt squint would dispel any thought of similarity with a bass reflex design - if we are indeed talking about the DTQWT. I'd half-cheekily say that it has more in common with a waveguide.

Disagree completely.   (Yes, we are talking about the same thing)..... perhaps we have a terminology different (?!)

 

1. "waveguide"....

Does not allow the rear radiation of the driver to escape anywhere

Constrains the front radiation of the driver

 

2.   "bass reflex"

The front radiation of the driver is allowed free

The rear radiation of the driver goes into a chamber, which has a hole in it .... the pressure escapes through this hole.

 

 

DTQWT is not #1 .... and is is #2.

 

What is the difference between "bass reflex", and a "rear loaded horn"....   Only the where you define the line between "the box", and "the port".    DTQWT is just a "small box, with an enormous port".

 

Like I said... .it's does't matter.    ;):D 

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Pictures are much more effective....  :)

 

The point being that a QWT is a variation of a BR ....   as is everything which encloses the back of the driver, and lets it out eventually....

 

 

You could say that that the arrangement behind the driver in a QWT is a "waveguide" .... sure, it's a structure which is guiding the rear radiation of the driver.... but then the "port" in a "BR" is equally a "waveguide"....   and neither of these things fit the typical definition of "waveguide" which is as drawn below.

 

 

301830244_IMG_1460(1).thumb.jpg.63b55824390ec8d393ea2b1e97562bfb.jpg

Edited by davewantsmoore
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(I did look it up) I see BR as having a vent designed to modify the behaviour of enclosed air, specifically WRT the resonance frequency of the driver. The DTQWT doesn't attempt that, hence my surprise.

 

The rear of the DTQWT drivers could be seen as radiating into the external environment, almost as much as the front radiation. The opening of this box is very large; I wouldn't consider that it is a controlling pressure regulator like a BR vent. It is, but to nothing like that degree.

 

Glad you got where I was heading with the waveguide thing - to complete the idea, I was referring to how the waveguide, and the horn/tube, both give an acoustical boost to the lower frequencies, directionality notwithstanding. (That's legal-speak for "don't even bother trying, this sentence will never make sense).

 

I think "DTQWT" describes these speakers most meaningfully - they are rather unique, well worth the several years it takes for "DTQWT" to roll off the tongue reliably in conversation. It's so easy to type, though!

 

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3 hours ago, BioBrian said:

The DTQWT doesn't attempt that

Sure it does....  ;)

 

Don't worry, even TG says "it's very different to a BR".  Heh.  (shakeshead).  Maybe I'll bang on about this more another time.

 

 

These are all just "vented boxes" .... where the shape of the box, and the shape of the vent are different sizes/shapes.     Sure, the QWT is better than many   :)

 

 

Here's another example.   They call this a 'horn'.   Is it really?!   ?B) 

 

tapped-horn.png?w=525

 

Edited by davewantsmoore
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I must agree, 3-dimensional horns should be the only ones to deserve the name 'horn'. Our mate Linc can certainly hold his head high.

Image resultImage result

 

French Horn                                                                                                                     Cor Anglais  (English Horn with a French name)

 

Edited by BioBrian
Too much fresh air
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Only a few hours have passed since my last post and I am outdated again ..... do you go very fast or does the time difference affect me exclusively? ( jet lang ? ) :emot-bang:
I have to deduce then:

Brian has built a new project but changing controllers and crossover networks but with the same boxes of the previous project. I read the last post of the link of his great work (that is to put desire, man!), I think there is no other.

I also deduce that the bass sector of its construction is not a horn ..... I see an open baflfe, and I swear I'm sober ..... correct please, maybe I need an urgent consultation with the eye doctor or with the neurologist ...

Generalizing a lot, I believe that a small waveguide is just a small horn ..... on a tweeter as they use DTQWT helps and much to the dispersion of the treble on all axes and in turn increases the SPL.
At low frequencies, it's another story.
If you have had the opportunity to listen to the great American classic bass cabinets, you will find the three great brands that made history.
JBL, who occasionally used horns for their projects and I think it would be hard to find an example on the web.
Electro voice, which I use horns and believe me, were two very different sounds. Dry and fast JBL, deep EV and with tremendous sound stage. Like Altec, they were preferred by musicians in their outdoor shows.
VOTT is too well known and famous for me to open my mouth here about him.
I have read that the reason for this difference is that the horns,,  when the larger they are, the more faveceren the coupling (acoustic impedance) between the cone of the speaker and the air. They have other problems, purists say, but the sensation of presence they offer is not achieved by the boxes or closed or with ports.
I think Dave's drawing is overlooking this typical horn phenomenon.
There were four days of rain here, I will go out to the garden to take some sun, we are in Autumn and it makes a summer temperature, heat and humidity ... my bones need to eliminate the accumulated internal humidity ......:angry:
 

Edited by arpavieja78
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6 hours ago, arpavieja78 said:

I have read that the reason for this difference is that the horns,,  when the larger they are, the more faveceren the coupling (acoustic impedance) between the cone of the speaker and the air.

 

Yes, result is some combination of higher SPL and increased directivity.

 

Quote

I think Dave's drawing is overlooking this typical horn phenomenon.

Not "overlooking it" .... Just not focussing on it too much ;)

 

6 hours ago, arpavieja78 said:

VOTT is too well known and famous for me to open my mouth here about him.

Nice example.   This is not a very horn loaded bass.

 

The horn (in the A7 cabinet for example) only works above ~200Hz ...... otherwise, it is a BR box.   People say, oh the "horn loaded bass is awesome".... but there is none  ;) 

 

 

Don't get me wrong, this is all just fun "semantics" ..... and "what's in a name?".    The point is the for speakers where the rear radiation is enclosed in a space and the pressure eventually makes it out to join with the front radiation .... are all really the same type of box.    Of course, they come in all different shapes and sizes (like everything) with different performance.    The way to fundamentally understand them (and how to model them, etc.), is to realise they are all variations of the same thing  (as much as the "marketing department" will struggle against that).

Edited by davewantsmoore
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14 hours ago, davewantsmoore said:

 

Don't get me wrong, this is all just fun "semantics" ..... 

 

Of course, we are doing a bit of relaxation, and I assume that I have a slightly light mouth .......;)  I have been looking for and found examples of classic JBL horns, Paragon, Hartsfield, among them. But I was referring to the PA line ...

 

 

 

We had a terrible time here, and this picture came out in a diary.

And I remembered a professor (far away in time) who explained that this photo is actually a giant capacitor of Mother Nature. Do not ever forget, good examples to support the theory help a lot, but the enthusiasm with which they are transmitted is an important part too, nothing more boring than a purely mathematical teacher .....

The atmosphere is positive, the earth the negative. The air is dielectric, but it is loaded with moisture, and when this humidity exceeds a limit, a leak occurs, the electrons of different charges are joined and boooommmmmmmmmmmm, fall a few hundred thousand volts that we call lightning. I'm still fascinated......:o

Tormenta en Buenos Aires 30-04-18.jpg

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On 29/04/2018 at 7:40 PM, BioBrian said:

 

"For that reason, I think that the best of the worlds is enjoyed by those who can hear something like that, in the open air. Do not worry about phases or reverberations, like the sound of thunder, everything that comes out of there, will dissipate in a native way"

 

Brian

 

Thanks Brian ! :D

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15 hours ago, davewantsmoore said:

 

 

The horn (in the A7 cabinet for example) only works above ~200Hz ...... otherwise, it is a BR box.   People say, oh the "horn loaded bass is awesome".... but there is none  ;) 

 

 

 

I once listened to the Altec Nineteen, the specs say 30 hertz, but less how many DB? Anyway, they impressed ...

The team was:

Teac TN400
SME with Shure V-15 Type III
Mc Intosh MA6100
Altec Lansing Nineteen
Direct cut vinyl, Carmen de Bizet, that was exciting!
I do not remember the director, but surely it was not Stokowsky!

-----------------------------------------------------------------
And when a friend who traveled to the USA asked me for advice, and I was afraid of the cost of luggage, I recommended AR-15 and a good power amplifier, a Sony of 120 Watts rms per channel ...... When we put it in operation, I had to work hard to show enthusiasm for the sound achieved .....
From there, I always say: small boxes, small sound, big boxes, big sound. There is no escape .

----------------------------------------------------

 

( See quote )

All Vott models will have better bass if we take advantage of the gain of the room......:P

Place them in a corner, or you can also exchange them for a Klipschorn ....... This improves the WAF automatically, too..... :o

 

https://greatplainsaudio.com/altec-lansing-library/altec-lansing-voice-theatre-vott/

---------------------------------------------------

Happy Labor Day to all !

 

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  • 1 year later...

Greetings Gents. A while since I checked in on this thread. 

 

A quick up date--The Problem:

 

I've been living with the DTQWT-iii's for a while now, and the creeping realization finally burst into consciousness that something is wrong, something is missing, that these speakers leave me feeling disappointed every time I listen to them. I had almost made up my mind to move on to another speaker build and abandon these speakers to office background duty at work. Before making that final, I also considered bi-amping or tri-amping with an active  cross-over to replace the speaker's internal cross over, and while reading about the cross over points on Troels' website I found "it"! I discovered the problem and the solution all in one.

 

The Shameful Solution:

 

Normally, I wouldn't admit to this, but it was such an easy mistake to make, at least for me, that I wondered if some of you might have done the same thing. It's careless, it's sloppy, I admit it. And ridiculous, since I took such care in building the speaker. Anyway, here it is:  To get the tweeter and midrange in phase with each other, we have to reverse the polarity of the tweeter. Troels' cross over diagram shows this, if you look carefully, and the text states it explicitly. 

 

Five minutes with a philips screwdriver and a soldering iron, and I had a new pair of speakers entirely. No longer is there a sense of them being somewhat listless, un lively and somewhat veiled. That's made ALL the difference.

 

So . . . I hope that helps, or better yet, I hope that doesn't help anyone at all because everyone was more careful than me. 

 

Happy Troeling.

 

Brenton

Edited by Tube Nube
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Greetings Gents. A while since I checked in on this thread. 
 
A quick up date--The Problem:
 
I've been living with the DTQWT-iii's for a while now, and the creeping realization finally burst into consciousness that something is wrong, something is missing, that these speakers leave me feeling disappointed every time I listen to them. I had almost made up my mind to move on to another speaker build and abandon these speakers to office background duty at work. Before making that final, I also considered bi-amping or tri-amping with an active  cross-over to replace the speaker's internal cross over, and while reading about the cross over points on Troels' website I found "it"! I discovered the problem and the solution all in one.
 
The Shameful Solution:
 
Normally, I wouldn't admit to this, but it was such an easy mistake to make, at least for me, that I wondered if some of you might have done the same thing. It's careless, it's sloppy, I admit it. And ridiculous, since I took such care in building the speaker. Anyway, here it is:  To get the tweeter and midrange in phase with each other, we have to reverse the polarity of the tweeter. Troels' cross over diagram shows this, if you look carefully, and the text states it explicitly. 
 
Five minutes with a philips screwdriver and a soldering iron, and I had a new pair of speakers entirely. No longer is there a sense of them being somewhat listless, un lively and somewhat veiled. That's made ALL the difference.
 
So . . . I hope that helps, or better yet, I hope that doesn't help anyone at all because everyone was more careful than me. 
 
Happy Troeling.
 
Brenton
Easily done, I'll admit I have done the same in the past.

Iv always been interested in the troels dtqwt. I guy I loosely know has both these (don't know what series) and the statements ii and he says that he preference is the statements.

An interesting comparison from two great designers and their 'best shot'
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Interesting W_L that your friend prefers the Statements. I also considered the DTQWT but ended up building the Statements and was never able to compare them directly. I am about to upgrade them to Statement II.

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  • 2 months later...

I was having an afternoon home alone yesterday playing a few favourite records ....

 

Hard to believe it has been 7 years since I built these speakers ....

 

They are still going strong and I am still loving them.

 

I did crank the volume a bit when playing the Alan Parsons Project tracks Sirius & Eye In The Sky  :P

 

 

01.jpg

02.jpg

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@Sierra I remember being out there Al when you first built these and the room doesn't look like it's changed at all. Did you have those plates rattlin' in the china cabinet at 107.7db?:ohmy:

 

Glad they're still sounding great, mate.

 

Cheers,

 

Keith

Edited by cheekyboy
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2 minutes ago, cheekyboy said:

I remember being out there Al when you first built these and the room doesn't look like it's changed at all. Did you have those plates rattling in the china cabinet at 107.7db?:ohmy:

 

Glad they're still sounding great, mate.

 

Cheers,

 

Keith

 

Cheers Keith,

 

Indeed ... not much has changed over the years ... lol

 

Haha ... yes the china cabinet does rattle at times ... but @ 107 db no rattles were to be heard  :P

 

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12 minutes ago, cheekyboy said:

@Sierra I remember being out there Al when you first built these and the room doesn't look like it's changed at all. Did you have those plates rattlin' in the china cabinet at 107.7db?:ohmy:

 

Glad they're still sounding great, mate.

 

Cheers,

 

Keith

Yeah good memories being assailed by the Troels, looks like you still haven't replaced the plinth on the Technics TT @Sierra !

Are those blocks of wood for the project still in the corner? 🤔

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35 minutes ago, evil c said:

Yeah good memories being assailed by the Troels, looks like you still haven't replaced the plinth on the Technics TT @Sierra !

Are those blocks of wood for the project still in the corner? 🤔

 @evil c The Technics plinth is still a work in progress ... albeit not much progress I must admit ... 

Meanwhile the Jarrah blocks are "seasoning" nicely ... :P

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5 minutes ago, Sierra said:

 @evil c The Technics plinth is still a work in progress ... albeit not much progress I must admit ... 

Meanwhile the Jarrah blocks are "seasoning" nicely ... :P

I knew it!! 😄

Sadly distracted by other passions, with a dose of procrastination thrown in. 

All been there !,😉

Edited by evil c
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7 minutes ago, evil c said:

I knew it!! 😄

Sadly distracted by other passions, with a dose of procrastination thrown in. 

All been there !,😉

Other passions have taken precedence this is true ... 2020 is the year that it needs to get done.

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Hi @Sierra, great to hear these are going well - 2012 seems like a lifetime ago.

 

I love the way your Jarrah has kept its redness, and the contrast with the pale "Tas Oak" (gum trees). The stuff we are sold under that name down here is more orange-brown, I think more like your side veneer. The eucalypts that grow above my house have this nice pale yellow colour; you did well I think. (Don't use it for fence posts though - they rot out in 5 years). This pic is from your first page, nearly 8 years ago, and they look even redder now. (In contrast, my myrtle has faded from red to a non-descript brown).

 

There was some lovely work going on here. Pity it's on the inside 🙂, but good to know it's all still there.

 

 

post-103929-0-42610000-1349160567_thumb.

 

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Hey @BioBrian ... Yes mate they are still going well.

If I really like something I tend to hang onto it ... and these for me are a keeper.

 

Both the timbers have darkened over time ... the Jarrah doesn't quite have the redness that it originally had and the Tassie Oak has shifted to a more yellowish hue.
The Tassie Oak veneer has changed in the same way as the solid timber on the front baffle so they blend nicely and look coherent.

 

A slightly better pic of the color change below.

And considering they sit in the lounge room where it gets full sun in the afternoons (not direct) they have held up very well.

Shame about your myrtle fading though.

 

 

 

 

DTQWT.jpg

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