Line source adventures 
Monday, January 16, 2017, 13:27
Posted by Anders
After having seen several compact line source designs based on small full range drivers pop up in the product offerings from big name manufacturers I became intrigued and decided to give this a try.

The Faital Pro 3Fe22 driver seemed too be a good choice since they perform very well, have decent power handling and are affordable in larger quantities.

I decided on a sealed system with ~1,3dm3/driver when sectioning them in groups of four, and it works fine when combined with some low end support, in this case by two THAM10's loaded with Faital Pro 10HP1020.

Drawing:


Build:


Setup:


I'm currently using a Linux loaded skylake I3 NUC with a HRT microstreamer D/A as source, processed by a DBX Drivereack 260 and powered by two LabGruppen IP450's.

The system sound very clean and hints of having a lot of headroom if needed, no doubt it is overkill in the current application, but it sounds really good so I'm happy.
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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 :



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

Advanced...


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?
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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 :)
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