More TPQWR ponderings... 
Thursday, December 31, 2015, 11:03
Posted by Anders
The previously mentioned mix of principles we choose to call TPQWR seems to have a lot going for it, below you can see an 15" example model and a comparison to the THAM15 loaded with the same driver.

TPQWR is short for Tapped Pipe (meaning a constant area segment) coupled with a Quarter Wave Resonator (another constant area segment).

These two segments are tapped at the driver and the resonator is the last segment leading up to the mouth.

The middle peak in the response is the result of the QWR segment, this also boosts the efficiency in the entire passband, the upper and lower bandpass limits are a product of the pipe segment length.

The typical TPQWR enclosure will be bigger then it's THAM equivalent, that much is certain, how much bigger is not yet known since we have yet to optimize the TPQWR folding and size to the same level as for the THAM designs.

Example model :

THAM15 (grey) TPQWR115 (black) 15TBX100 2PI comparison :

view entry ( 2098 views )   |  permalink   |  print article   |   ( 3 / 34137 )

TPQWR - an easy to build mix of principles  
Wednesday, November 11, 2015, 21:16
Posted by Anders
Johannes Rodin came up with something very interesting...

The following images serves to describe the principal idea and is not to be regarded as any form of optimized DIY build plan, for example the oh so necessary bracing is left out.

Named TPQWR since it seems to describe the mix of principles involved in the best way, a Tapped Pipe coupled with a Quarter Wave Resonator.

The front resonator is the key according to Johannes, it boosts the tapped pipe's entire pass band efficiency and also adds a bit of extra efficiency in a region where it usually is beneficial to have it.

Simulations seems to indicate (speculative) that it will have very low "in pass band"-distortion due to extensive upper harmonics cancelations and that it will show less tonal deviations due to power compression compared to other design principles.

This mix of design principles is also very simple to build and it has about as good of a volumetric efficiency as it is possible to achieve being completely devoid of unused volumes when folded.

Principal model without necessary bracing:

Principal drawing without necessary bracing:

Faital Pro 10PR330 in 2PI:

B&C 10NW64 in 2PI:

Faital Pro 10HP1020 in 2PI:

Faital Pro 10HP1020 in 1PI:

Faital Pro 10HP1020 in 0,5PI:

More driver examples may be added in the future.
view entry ( 1999 views )   |  permalink   |  print article   |   ( 3 / 34201 )

Wednesday, March 25, 2015, 20:54
Posted by Anders
A new DIY project takes shape :)


Very advanced indeed...
(the source resistor is changed from 0,5 to 0,75 Ohms)

Closeup of the I/O stage

Overview of a more complete, but not finished, amplifier

Can it get simpler then this without involving depletion mode FET's and transformers?
view entry ( 2253 views )   |  permalink   |  print article   |   ( 3 / 56134 )

2" fullrange TB W2803SE on JBL 2386 upgrade 
Sunday, February 22, 2015, 18:00
Posted by Anders
I have updated my crazy top system, there is a new 2" full range driver, the Tangband W2-803SE, and some new higher grade components for the filter, 10uF capacitor over a 10 Ohm resistor, simple enough.

This is what it looks like:

The measurement setup, in the middle of the room, 1m above the floor and at 1m distance :

Raw measurement, no active processing:

1st parametric equalizer:

1:st parametric equalizer result:

2:nd parametric equalizer:

Active high pass filtering:

Final result (all of the above):

Impressive result considering the components are worlds apart and the really simple passive circuit, it actually sound rather good even before the active processing, but since i have the tools, why not use them right :)
view entry ( 2589 views )   |  permalink   |  print article   |   ( 3 / 60996 )

new place - new refinements of madness 
Monday, February 16, 2015, 19:31
Posted by Anders
My total disrespect for proven solutions and conventional thinking has reached new heights, seeing as my 2" full range drivers on JBL 2386 horns "solution" did not quite satisfy my need to provoke.

So what can you do with some way to small left over pieces of wood and a pair of decent size low frequency drivers? and how can it improve upon an already pretty far out top system?

Well... let's think outside the box, way outside the box, in fact, lets forget about boxes all together, this new set up is completely box-less and is built from just enough wood to complete a cup holder or two, that effectively eliminates the open baffle option that I know you where thinking of.

With some slight EQ the 24" drivers preform well down to and slightly below 30Hz, and can be crossed high enough to provide a seamless integration with the 2" fullrangers in the JBL horns at around 300Hz.

These drivers can almost to be regarded as a two-in-one solution, both driver and an open baffle design all in one, only in this case the baffle support is called cone :)
view entry ( 1342 views )   |  permalink   |  print article   |   ( 3.1 / 60735 )

<<First <Back | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | Next> Last>>