Turning Japanese...

[pinkmouse]

Well, a new interstitial system is born!

After a few years hiatus, before Christmas the urge to build something and get back into serious music listening was reborn. The seed was one track played on Stuart Maconie's excellent show on BBC 6Music, The Even Freakier Zone, a late night show of extreme weirdness. The track was Blinkgurtel, (by Hallo Gallo, an offshoot of German band Neu), so mind blowing I got out of bed, rushed down to the computer, and ordered it online immediately. Problem was, my old system was very tired, and my long ongoing active threeway was stalled, so I went to my stock of drivers, and dug out some Coral 10" and JVC Leaf tweets. First problem, I couldn't find my SoundEasy dongle, so had to rely on measurements of the Coral I'd taken previously, rather than using that program to model a suitable box.

So, using the various free calculators available, an enclosure was designed, deliberately oversized by 10%, so I could tweak later. Construction was 18mm ply on the front, and 12mm MDF, very, very, well cross-braced, simply because that's all I had in stock at the time.

Here's a pic of the system so far, more to follow.

[pinkmouse]

The next step was how to drive and crossover the system. This really was a no brainer. I dug out my DCX, that had been gathering dust for a while, and used a couple of LM4780s on my own PCBs, built into a case from an old Crown paging amp. Simple and easy, with the advantage that I had all the bits in stock. Connection to the speakers was made with Neutrik NL4 speakons, to avoid the risk of miswiring. Frontend consists of VSPS from Rega 3, and ancient iBook running as an iTunes client from all my CDs burnt to my NAS, all plugged into SY's Heretical Line Stage.

Wiring still in progress in this pic!

[pinkmouse]

So, all was going to plan, I'd even found my SE dongle to do some measuring. But life is never that easy, (at least for me! ), and when I went to fire up my very old Windoze laptop, it was dead. Perfect impression of a Norwegian Blue. Piffle.

So, I set the crossover by ear and reference to the FR plots I'd shown here in my old SE thread, and was pleasantly surprised, nice!

Then my whole life changed. T'was my birthday last week, and my dear old Mum very generously gave me a brand new 13" Macbook Pro. So, after getting all my mac SW transferred, last night I set up Bootcamp, enabling me to run Windoze, and this morning, I've been installing SE. Still need to install drivers for the M Audio Transit, and set up all the configuration, but so far, it's working!!!

[wintermute]

Hi Al, Interesting project! The bug never leaves does it I go through long periods of no DIY'ing but eventually get the urge to start again. My biggest problem is finishing things!! I tend to get too obsessive and burn out for a while.

It's funny I was looking at the first pic and thinking what's that funny black disk, then the penny dropped! It is so long since I've seen a 45 that my brain just didn't register what it was!

Are they going to be used nearfield? or is that tweeter able to be crossed really low? Or are you just not worried about directionality in general?

Tony.

[pinkmouse]

Originally Posted by wintermute

Are they going to be used nearfield? or is that tweeter able to be crossed really low? Or are you just not worried about directionality in general?

Well, my front room is nearly nearfield as it's so small! This whole thing is a bit of fun, just to have something to play with whilst long term I design and build a fully active HT system. I'll be happy with reasonable on-axis performance as I live alone, (can you tell from the mess? ), so the Corals should go just about high enough for that, but we'll see when I do some measuring. That has been temporarily put on hold whilst I run some Cat5, but I hope to be able to post something later today. Meanwhile, time for a couple of fried egg butties before I pick up the hammer drill again.

[pinkmouse]

Just a quick update, I've been distracted by issues with my NAS and iTunes, (now sorted) as I wanted to use my old iBook as a music source in the system. I've also been having problems with my M-Audio transit refusing to run in full 24/96 mode, despite being on an USB 2 port. That is still not sorted, despite the latest Bootcamp drivers. Next thing to try is an upgrade to XP SP3 from the SP2 I'm currently running, to see if that makes a difference. Of course, I can still measure, but only at 24/48, and I'd prefer to get all this stuff sorted first so it's done and I can forget about it.

[wintermute]

be prepared for a shedload of "updates" after the installation of sp3 Not saying don't do it, just don't be suprised at how many megabytes of updates there are next time you connect to windows update!

Do you really need the 96Khz sampling? The 48Khz gives you usable data up to 24Khz, and you will get better low frequency resolution. I was also going for the 96Khz but forgot that the lower frequencies ended up with much lower resolution. Unless of course you want to check for harmonics or resonances in the higher frequency ranges From what I tested 96Khz didn't seem to make any difference except showing me that my tweeter is down about 37db at 43Khz and has a slight bump at about 30khz...

Oh and I lived in a bedsit for 9 years the three ways (75L cabinets) dominated the room somewhat The total area including kitchenette and bathroom was 15 square meters!

A fully active HT system!!!! that's a LOT of amp channels (unless you go full range for the surround speakers).

Tony.

[picowallspeaker]

I have also 4 japanese ! One almost dead
I also made a deliberately big box , with 'reggae' in mind .
The 'big one' is a Kenwood-Trio from the 777 Series ,the other an old fashion FR with a big white whizzer . Best musically , just a coil and a cap ...still under construction 'cos one of the two (the most efficient !!!) just received 10 times more the power it can sustain ...but when trying other steeps and slopes,ways and speakers ,the 'less is best' is a winner .

[pinkmouse]

Originally Posted by wintermute

...Do you really need the 96Khz sampling?

Nah, not really, but y'know...

A fully active HT system!!!! that's a LOT of amp channels (unless you go full range for the surround speakers).

Yup! Thirteen plus subs! I have a lot of Toshiba outputs that need a home.

[pinkmouse]

Originally Posted by picowallspeaker

...but when trying other steeps and slopes,ways and speakers ,the 'less is best' is a winner .

The problem with these drivers is that I'm running them very near to their limits, so steep crossovers are probably required. I've set LR24 at 3.6K as an interim, but when I get some measurements, I'm sure that will change.