I have no fancy measuring equipment but when I use TrueRTA to generate frequencies I can hear all the way down to 24hz, anything below that is just silent but the drivers are "moving"... I dont know if thats means the drivers go down to 24hz or not but that proves 24hz frequencies are atleast detectable with my ears
I'm very glad to hear that...
now I just have to figure out which bank to rob to gather money for the project
Thanks, Ipppe
I'm really getting wormed up to make those speakers, and since I'm a professional doublebass player I'm really interested in good natural deep bass. I was a bit disappointed to read PK comment in another thread diyAudio - View Single Post - Troels' design has been completed (JA8008/TW034 DTQWT) that bass doesn't go super low. Yet on Troel's site there are some in room measurements that show bass all the way to 20HZ...
Hi Bassivus,
I just saw this reference to my previous statements about the DTQWT's. Remember that my impression was based on only few minutes listening to the speakers with material unknown to me, so I would clearly have more faith in Ipppe's impressions than in mine!
Best regards
Peter
true 3 way?
I have also been considering this design but with locally available budget drivers for a first speaker project.
Is this design really a 2 way with added bass drivers as the mid is not high passed? i thought the idea of a 3 way was for the mid not to have to cope with bass duties!
Could an alternative be create small chamber for the mid plus hi pass filter and use only one tqwt for the bass drivers making a true 3 way?
Any comments?
I have also been considering this design but with locally available budget drivers for a first speaker project.
Is this design really a 2 way with added bass drivers as the mid is not high passed? i thought the idea of a 3 way was for the mid not to have to cope with bass duties!
Could an alternative be create small chamber for the mid plus hi pass filter and use only one tqwt for the bass drivers making a true 3 way?
Any comments?
Changing the DTQWT in any way will give you another speaker and the result is hardly predictable. After 27 years hunting the perfect speaker for me I finally found it after been listening to the DTQWT at Troels' place. I've build it and I'm fully satisfied.
I suggest you reread the article at Troels' website regarding the design.
Quote: "All drivers load a center horn and you may ask whether the large bass drivers won't have an impact on the front driver from sharing the same open space and the answer is yes - and this is intentional.
Air goes where pressure is low, thus when the rear bass drivers move inwards, they will push air into the large center horn and by doing so they will suck air from the front horn and pull the membrane of the front driver. Obviously the front driver will do the same thing for the bass drivers. We have a situation similar to a push-push configuration of two opposite placed bass drivers in a vented cabinet.
The subjective experience from this is a cleaner midrange, distortion has been lowered at high SPLs and yes - we have more bass. In fact a lot more bass. The typical quality of the bass from a horn is quite different from conventional high mass/low efficiency bass drivers in small vented enclosures. The DTQWT delivers deep, dynamic and dry bass - anything but boomy."
true 3 way?
hi yea
i have poured over troels site several times and i get the horn loading idea (if i had$3000 i would be buying without question!!).but i am just wishing to understand the electrical signal to midrange.as in this design the midrange it appears to be given the bass frequencies which seems to leave in the downside of a 2 way having to do bass and mid!
hi yea
i have poured over troels site several times and i get the horn loading idea (if i had$3000 i would be buying without question!!).but i am just wishing to understand the electrical signal to midrange.as in this design the midrange it appears to be given the bass frequencies which seems to leave in the downside of a 2 way having to do bass and mid!
A few minute's work with Akabak, or even with Falstad's ripple tank simulator, will show that the opposite occurs. Venturi effect, which Troels described, is insignificant at the low air speeds present in the DTQWT and is completely swamped by the pressure effects.
If one push a bass driver at the back you'll see the bass/midrange driver will be sucked in. Tommy Hørning at Tommy Hørning website do have a Danish patent for this arrangement. Check the Agathon Ultimate reviews around.
As far as I remember Troels only claims the reduction in distortion at high sound levels where it matters most.
Hearing is believing.
Yes, the midrange driver also plays bass. But the midrange driver is in control by the bass drivers and therefore barely moves. Even at extreme high sound levels I'm impressed by the very small movement of all drivers. Freaking low distortion to my ears. Comparable to ESL in my ears.
Furthermore cabinet resonances are none significant in this design.
Unlike the ESLs the DTQWT is truly dynamic and able to scale all acoustic instruments to lifelike size (ESLs can scale them too but not compete when it comes to dynamics). Most impressive is the double bass. OMG!
Your killing me... I cant wait anymore gotta make one soon... Most impressive is the double bass. OMG!
Please please
...c'mon
or I'm going 
Nice to see this thread coming alive again
I would think to a "beginner" the design of the DTQWT speaker looks more difficult than it actually is... If you want, you could build them with a basic circular saw and a simple router for the driver holes... As with every project the hard part is the final finish, whether you want to paint it or use veneer the final steps take way longer than the actual construction...
But you COULD build them entirely with mdf and then roll a coat of cheap paint on them and have the same sound as everyone else who built DTQWT speaker
I bet you could build them in 2 days if you dont give a crap about looks...Having used them for about 1.5 years now almost every day, all I can say is that they sound absolutely amazing... I still havent heard anything better than my precious DTQWT's
And my Jungson amp brings the final touch towards near perfect sound (According to me)... With performance like this for a fraction of the cost of any high-end system you would make any hifi-enthusiast jealous
If you hezitate, DONT!
Maybe all builders should start a DTQWT fanclub
Happy to se this thread is still alive
The consept with the rear mounted drivers and the theory of the pressure moving around in the "horn" had me wondering if Troels explenation was correct. Espessialy when the two drivers (front / rear) are moving at different frequencies. In my head this could result in an increase in distortion. But according to Don's evaluation the front driver won't be much affected by this, and the negative effects are more or less neglectible. To turn this around, won't this be the case on the positive side as well? The positive effect of this is almost neglectible?
Don't get me wrong, I'm absolutly concidering to build a pair of DTQWT for my HT. Janzen is supplying the complete kit (exept for the 4 10" bassdrivers) at a resonable price (890 EUR incl. VAT.) in my eyes. I'm just curious about the construction and theory
The consept with the rear mounted drivers and the theory of the pressure moving around in the "horn" had me wondering if Troels explenation was correct. Espessialy when the two drivers (front / rear) are moving at different frequencies. In my head this could result in an increase in distortion. But according to Don's evaluation the front driver won't be much affected by this, and the negative effects are more or less neglectible. To turn this around, won't this be the case on the positive side as well? The positive effect of this is almost neglectible?
Don't get me wrong, I'm absolutly concidering to build a pair of DTQWT for my HT. Janzen is supplying the complete kit (exept for the 4 10" bassdrivers) at a resonable price (890 EUR incl. VAT.) in my eyes. I'm just curious about the construction and theory
i think i may have convinced myself to build this one.
id also like to use a real wood on the front. i like the creativity of using in essence a butcher block for the front, way cool!
is it really that difficult to use solid wood that is somewhat stable for the front piece?
another choice is to use mdf and glue a piece of solid wood on top of it to ensure dimensional stability. thoughts anyone?
buzz, i can see this project implemented with some beutiful aussie jarrah wood....
id also like to use a real wood on the front. i like the creativity of using in essence a butcher block for the front, way cool!
is it really that difficult to use solid wood that is somewhat stable for the front piece?
another choice is to use mdf and glue a piece of solid wood on top of it to ensure dimensional stability. thoughts anyone?
buzz, i can see this project implemented with some beutiful aussie jarrah wood....
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To the guys that have built these speakers I have 2 questions.
My first question is have you hear the wilson watt/puppy and can you compare and contrast the sound of the DTQWT to these speakers. I am picking these speakers because they are a "standard" and because I recently had a chance to hear them in a nice room and was very impressed by their midrange and bass.
My second question is have any of you had a chance to try these speakers on a low powered SET? These speakers are about as efficient as the ones I have now but Troels doesn't recommend them for SET on his site.
My first question is have you hear the wilson watt/puppy and can you compare and contrast the sound of the DTQWT to these speakers. I am picking these speakers because they are a "standard" and because I recently had a chance to hear them in a nice room and was very impressed by their midrange and bass.
My second question is have any of you had a chance to try these speakers on a low powered SET? These speakers are about as efficient as the ones I have now but Troels doesn't recommend them for SET on his site.
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