Another life-long objective fulfilled… my very own Mark Levinson power amp. It’s the current model as well. In the flesh it is truly a beautiful beast. It weighs in a full 52kg of precision machined metals, high quality parts and components.

To say the improvement is night and day against my current Rotel RMB1066 is being conservative. There is just to comparison in terms of sound quality btw these two. Considering the price diff, that should be a given.

I’ve always felt that the mid-bass and lower mid from my DIY floorstander to be ‘lacking’. After countless times of xo tweaking, it never really sound right. Today, I finally discover the root of the problem - there was just not enough power to drive the scanspeaks speakers. With 400w into 8ohm and doubling to 800w at 4ohm, there is more than sufficient headroom to drive most speakers to unrealistic levels.

I can imagine myself thumbing through my fav CD collection over the next few weeks. There can be no regret getting this unit ;D

Sold off the Krell for a fair sum of $3300. Mighty glad I hold off and stick to the asking price. Lots of low-ballers coming in below $3k.

  
The DIY-center finishing is completed - not exactly as intended. But still looks good. Lacquering was not perfect and rub-down with water as lub caused some damaged

It finally has a ‘face’. I just could not resist giving it a trial run after installing the front baffle. The tw-mid is practically ready as it is a fully sealed sub-enclosure. The side panels have not been attached yet… but already it sounded fantastic.

It’s been a while since any hifi component gives me the goose bumps…. but this one did. Without the woofers, the vocals are good, very nice tonal balance, sharply focus, excellent separation - however, it was light, thin and without depth. After quickly put together a 2.5 crossover and the dual woofers in place, it just caught me pleasantly surprise. Playing the Shearfields Labs Drum Track, it sounded so good, I thought of leaving it the way it is….

All is not perfect yet… the bass could still be tighten up once the side panels are in. And the xo smoothen with better components. I’ve yet to see the impedence curve… hope it do not dip too low.

I really need to replace the Krell amp, just plain incompatible with the Lexicon. Or should I get rid of the Lexy instead…. I would think it is prob easier to rid the amp that the source comp!

Some update on this DIY center speaker;

Driver selection - completed
Cabinet simulation in UniBox - completed
CAD cabinet design - conceptual completed
Construction - work-in-progress
Will try and post some pics when available.

Uploaded dedicated webpage..

Just sold off my JmLab Electra CC900 center speaker on 10th Dec 2005. Managed to get a rather good price for it. The proceeds will be used to finance my next DIY project - will be rather ambitious this time in terms of drivers selection;

TW - 1x ScanSpeak D2904-700000
MID - 2x 12M/4631G00
WF - 2x 18W8545-00

At present, center duty is covered by ‘ol faithful B&W DM603.

Took delivery of 42pcs of acoustic foams from GCD Acoustics.

Bought a combi of 12x Egg Crate and 30x Spikey tiles - Grey. It did not occur to me earlier on how the f* that I’ll be mounting them on the walls. To cut to the chase, ended up spending a trip to IKEA for some lumber to fix up a makeshift cabinet to contain the darn thing.

Have plans to use the EC type for lining the interior of my new DIY speakers.

Been reading up on room acoustics treatments and especially standing waves or room modes, in most cases this deals with the lower register. The biggest tip in on speaker palcement. Skipping the complex maths, to eliminate anything below 80Hz (BASS), I’ll have to treat up to the 3rd harmonics - effectively, this works out to 1/4 the distance of EACH axis (L/W/H). Assumptions here is of coz two facing parallel walls. Odd shaped rooms are too complex to calculate and only thing left is experiment and trial+error.

Thus, having moved my WUF to 1/4 the length of the room, the sudden boom previously found when playing back specific tracks are largely eliminated!! :D

As for the foams, afte putting up two tower of foams, the highs are much more focused and mids less blurred. Addressing the 1st reflection via diffusion or absorbtion makes a hugh difference.

There you have it, another step on the journey to audio nirvana.

Wow!! It’s been almost 2 months without any blogs… it’s not like I’ve been terribly busy, more like super lazy.

Anyway, finally EJ came visiting and had a listen to my DIY speaker… almost immediately he detected some ‘missing’ freq… to cut to the chase, it prompted me to review the xo. Did some experimenting and finally ended up removing the mid/bass totally out of the xo circuit.. i.e. only the tweeter is with a high pass 2nd order.

Also took out the notch filter.. it sounded significantly better - the mids are much fuller, the bass also seems more rounded… hhmmmm think I’ve to redo this in the long run… actually was playing with the idea of rebuilding a new design with the ring radiator tweeters and a dedicated mid-range - thus a complete 3-way design.

From current xo values, the lowpass seems to be too low. Based on std 1st order, the cut off is less than 2kHz and the high pass 3.3kHz (2nd order). From simulation this gives a smooth and flat FR… but from actual listening, it is too thin on the mids.. haizz..

But at the end of the day, the ear is the deciding factor… thus, I am rethinking the xo design,… maybe lowering the HP and increasing the LP.. this may create a peak in the mids, but I think acoustically would be “sweet and warm”.

Now to get some CHEAP caps and inductors for testing..

A little late but there are 2 new updates to SF’s current line-up.
1st the one that makes me drool… Amati Aniversario:
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After a good 5 years, time to update me pc hardware… seeing that I already bought the ESI Juli@ soundcard, better if I setup the new sys inline with the eventual HTPC. (more…)

Azumanga Daioh! [preview]
This is one FUNNY series. Centers around the lives of a groups of teenage girls, school and their teachers. There’s a very unique characteristics of Jap anime humour,… see to understand, I shall not waste my time trying to describe it with my limited vocab. (more…)