New Midbass Fronthorns

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System Components

The pictures above are a little outdated: The Klipschorn on the left and the tall Eminence TH on the right are gone. Instead there is a Cinema Sub TH in each corner (refer to Tapped Horns page).

Also gone are the Yamaha DSP-AX1 6ch. HT Amp., the Behringer Ultracurve 2496 (which EQ'ed both Cinema Sub TH's) and the Albs Sub-25BB analogue subwoofer x-over (formerly used for the Cinema Sub TH's).

Instead a dedicated Playback PC with room correction came. It just runs JRiver as player software. Part of JRiver is a convolver engine for room correction an x-over duties. The convolver runs FIR filters created by Dr. Ulrich Brüggemann's Acourate toolbox. Many thanks here in particular to Markus and Heiner for their patience in answering my stupid questions!

XBMC had to leave as well since it does not have such nice convolver included as JRiver does. Sad but true. I liked XBMC so much. Music and movies are still stored on the network. A RME Fireface 800 serves as D/A converter. A three step attentuator between the D/A converter and the power amps serves as "safety parachute" for testing (I don't want to blow off drivers when something goes wrong inside the Playback PC resulting in full level to the power amps - ouch!).

 

Mains

 

Rear Speakers

My rear speakers are built from what's left over in previous projects:

Currently they are not even in operation since my system is limited to stereo only. This will change in future again.

 

Electronics

 

L-15D D-Amp

The SMSL SA-50 Class T amp had to leave because I built a stereo L-15D amp. It is based on the integrated analog input Class D audio amplifier driver IRS2092 and the digital audio MOSFET half bridge IRFI 4019. PCB designed and manufactured by LJM.
 
It's a class D half bridge audio stereo power amplifier with up to 250W/ch. @4 Ohm. It features a self-oscillating PWM topology with a self-oscillating frequency of approx. 400kHz.
 
As a power supply I choose the Connexelectronic SMPS500R with ±60V (running at ±59V). A separate speaker protection unit by Audiophnics is also included in the design (powered by the ±12VDC aux. output of the SMPS500R). Internal wiring is mainly done with twisted tin-plated single stranded wire of 0,8mm diameter. The electrolytic DC rejection capacitor on board the amp was replaced by a remote 22µF WIMA MKP10 capacitor.
 
Cost for the complete amp is approx. EUR 280,- including housing, ALPS volume control, power supply, two amp modules, terminals, wires, ferrite cores, consumables and S&H from China and France and Germany.
 
Compared to the SMSL SA-50 it is a set up in various means such as dynamics, punch and clarity. Just very pleasant sounding with authority when required. Power is more than sufficient for my application.

Here are some pics of it:

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The way it's built is more than influenced by Saarmichel (and others). Thanks for that!

 

 

Abletec ALC0300-1300 D-Amp

By chance I was able to participate in a group buy of these nice modules on the German diy-hifi-forum. Based on these modules I built two mono d-amp's to play with. There is the technical data from the manufacturer site:
 

 

ALC0300-1300 manual here...

 

After some searching, I finally choose a case of Modushop, Italy: The Galaxy Maggio Rato GX287 230x170 mm (1NGXA287N). The boards are installed isolated on 15mm plastic spacers . The PE of the power cord is applied to the chassis only.
 
The switch at the front has a red 12V LED (I did not find one with green LED). The LED can be connected to the amp PCB without a resistor - but for my personal favor I'll add one because it think it is too bright).
 
The holes I made with drill bits. Important is to cover surfaces with adhesive tape to prevent the anodizing to take damage from the clamping or chips while drilling.
 
The rubber foot under the housing Adam Hall PA enclosure feet 38x15 mm. Unbeatable for the price. Powercon plugs are used for the mains. They are really great: Super stable; and snap locked. A 3Gx1CY Ölflex cable fits fine. No comparison to an IEC connector. A round hole can also be drilled easier.
 
Finally, no hum or noise - just clean tight sound. They remain completely cold if driven at domestic levels.
 
Next step to come soon, is to switch from my current 2 way Acourate solution to "fully active". I'm very curious. I can now say already, that the integration of room correction with Acourate is so far the largest step forward I made in my system for a long time. Just after I switched off the convolver/correction for the first time for comparison with the "previous" sound, it became quickly clear, that there is no way back: Imaging, tactile response and tonal balance is just so much better now. Acourate in my eyes is petty much the best invest one can to to the system, if you are willing to carry the transition to a PC based listening system.
 

Here are some pics of it:

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