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Discussion Starter · #1 ·
Hello,

This is my second AV installation and it's now 4th year of service. I did the equipment installation and my wife made the blackout curtains for us. It is all very functional. All the AV equipment is commercial except for the speakers. I'm a DYI speaker enthusiast so the primary speakers are home brew.


My first DYI speakers were started in 1982. They featured JBL drivers and I measured the T-S parameters for use in proper enclosure sizing and tuning. It was a 6th order design using a DYI 2nd order active filter with a 6 dB boost at 22 Hz. Subsequent designs got larger and more complex.


Now with the benefit of retirement, I spent the last 18 mo downsizing the speaker setup. The intent was to save room, improve the appearance and at the same time improve the sound quality. I built new speakers and purchased 2 Behringer DCX2496 units to provides the capability to easily control the important aspects of the sound system. I upgraded my sound measuring capabilities and have spent much time investigating various audio configurations. It's been great.

Theater Equipment:

2- Rotel RMB1066, 6-channel power amps

Integra DTC 9.8 pre-pro

DirecTV HR20-700 sat receiver

Samsung BD-P2500 Blu-ray player

Mitsubishi HC3000U DLP projector (720p)

110 Da-Lite 16x9screen (96w x 54h)

DYI speakers (detail below)

Pictures:









Speakers:

FL-FR-CC DYI Speakers:

Seas ER18RNX H1456 midwoofers (6 1/2" reed/paper cone)

Seas 27TBCD/GB-DXT H1499 tweeters (25 mm metal alloy dome w/DXT lens)

Dayton TWC-0.38 curved cabinet (cherry finish)

Behringer DCX2496 provides; 2.4 kHz LR-24 XO, Time Delay, and EQ

SW DYI Speakers:

2 JBL 124H, 12" (same as JBL pro 2203H)

[each in a 2.5 cu-ft vented Box (1.9 cu-ft net vol.)]

Behringer DCX2496 provides; SW time delays, EQ, and B-12 cutoff filter @ 20 Hz

Surround Speakers:

Frazier model ?? (still need to downsize these)

10" MW, 2" x 6" Horn TW, passive XO @ 2.3 kHz

Behringer DCX2496 provides EQ B-24 cutoff filter @ 40 Hz

Measurement Equipment:

Laptop PC

Behringer ECM8000 microphone

PreSonus Inspire 1394 sound card

HOLMImpulse measurement software

Speaker System Notes:

I experiment frequently with various speaker setup options.

The attached info is from two of those setups. Setup 1 is a conventional alignment for LR-24 XO's between SW/MR and MR/TW handoffs. All drivers are in phase and time aligned resulting in a smooth FR and linear phase response. Setup 2 is an interesting work in process. It attempts to minimize the phase response while still using LR-24 XO's. This comes at the expense of phase linearity. The impulse response appears to be improved in spite of the very unusual setup needed to achieve this. These setups sound quite differently, but both sound very good. I still need to optimize setup 2 by fine tuning the delays, remove the 3 dB response sag through the upper bass range. Then I can try to decide if one setup sounds better.


Each graph shows a response curve for each of the 3 front speakers (with SW's). Each response curve is an average of 6 mic positions all within 1 m of the main listening position (similar to Audyssey setup recommendations). The average was then smoothed using 1/3 octave filtering.


The high freq rolloff is intended to approximate that used by Audyssey for 5.1 home theaters. There seems to be no lack of high freq detail this way even when using CD music, but at some point I will flatten it out to see if it makes a positive difference with CD's.


Setup 1:





Setup 2:





Regards,

John
 

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That's pretty-friggin' cool, man! Nice work!
 

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I really like the Rotel amps. That's a great system!! I have a Rotel intigrated amp (RA-2020) from 1979 that still sounds great. They make great equipment.
 

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Discussion Starter · #4 ·
Thanks for the comments.


Re the amps, These are my first Rotel amps. I have had them for 4 yrs now. I got tired of big stacks of 2 ch amps and purchased these. I thought they were a very good value and they had the input sensitivity adjustment feature I needed. They have worked great and I am very pleased with them.
 
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