The House of an audiophile Part 2 - The Cinema and Games room

This article is pretty useless without first reading the Part1, so if you haven't read that you will not understand the whys in this one.

Ok so I dealt with the first part of the problem with Part1... but that still leaves me with the even bigger, even more asymmetrical, prone to echoes and natural amplification of sound Cinema and Games Room.
There is another catch: the living room was supposed to have good sound, but this has to have good and powerful sound! If I'm having a party, this will be the disco.

The geometry, already discusses in Part 1 is...

...challenging.

So, again, after several tests and trials, and the obvious usage of my Galaxy Alpha phone as a sound analyser, I managed to sort things out this way: (for the geeks sake, I'm starting will the schematics and all the goodies, and I'll explain as I go.

 OK so this is far more complex (starting with the inputs... being a cinema and game room and all)!

The inputs start with the so full of glamour and on of the best CDPlayers EVER made the Nakamichi CD2P-E. This thing has been recapped and ouptup XOver trimmed so that all the possible musical details are pickup. This is an example of why a good old 16Bit DAC CDPlayer can eclipse an modern 24bit DAC cd player... I could talk for a year on this, but in very simple terms, think that the analog sound wave that you hear, once digitized is converted to a sort of bar chart of what the music would look like. Obviously, this loses resolution and that is why a true audiophile prefers vinils to CD's.
However, there are some excellent designs out there that can "imagine" the gap between the bars and recover the lost sound-wave. Some are good.. some are great and some are gods.
So in this sense, more bits = more resolution = better sound...no! CD's where recorded with a specific bit-stream in mind... having more bits does not mean that you have more resolution out of the CD, but rather you can decode more at once, and that allows you to have a bit-stream comparison on the recreation of the sound wave that could reduce conversion error.... so a 8 parallel chip 16bit circuit will easily eclipse a state of the art 24bit DAC (if the 16bit chips are really good).

Back then, while Philips created the TDA1541A 16bit DAC chip (and they did a VERY good job at that), they also created what is called a reference diagram, so that integrators could follow and create their own design. These diagrams normally are a schematic build to make the chip work and they are build long before the chip is made... so, by other words, no one ever tested the diagram.
Pioneer, sony, and all the other except Nakamichi and Arcam, decided to copy-paste the schematic and sell cd players.
Did it work? yes! Where they any good?.. no! they where all mostly dull and flat. Nakamichi and Arcam, however, waited for the chip, built their board based on the reference but not blindly, and then tweaked the output and voila! They unlocked the secrets of the brilliance of Philips TDA1541a chip design.
It is one of the best DAC out there!

The CD2P is rare for being very pure and precise in sound image, and shows you the best details in sound. It's that sort of player that makes you re-listen to all your collection because there was just too much you where missing.


As usual, loving he best ever build and being a child from the 70's-80's, I have my Amiga 1200 Tower connected to my media sytem.
You can see it here:

The rest is the typical Nintendo Wii, a Sony PS3 and a Roku3.

The AVR:

The AVR is a Denon4306... a true beast

This, is directly driving the Front L+R, the Midle L+R and the Rear L+R... and then it pre-outs the subwoofer and the Rear and Center channel to a set of slave amplifiers. The direct drive from the Denon outputs 8Ohm at 130RMS watts, and given the generous size of the capacitors, it's no wonder it can drive the speakers without getting tired when a lot of bass kicks in. The Denon has a capacity to resist starvation that is not all that common.


The central front slave to the Denon is no less than a Marantz PM55SE... yes it is a Ken Ishiwata tuned PM55... special edition.
A beauty...with a total harmonic distortion of 0.02%

This then drives directly a pair of B&W DM305. The 305 was an interesting project.
B&W where on the quest for a deep bass speaker made form light materials, that could reproduce across the range and not suffer form brittleness form the light materials resonance, and still provide some bass.
They created a Prism design backplane for the speaker that mimics the attenuator foam form the walls of any sound proof room.


























Did they succeed? NO! the bass is to soft (probably attenuated by the prism), however, they are EXCELLENT to reproduce voice channels... like the typical "dialogue" assignment that a THX system enrols the central channel into. So an initial deception as main speakers, transformed into a solution for the central channel. Driven by a powerlfull bu low distortion amp.


Back to the Amps... so I talked about the front, so how about the reinforced back?
The room architecture meant that rear needed power, so instead of buying extra big speakers and loose HIFI, I chose to spread the frequencies across multiple speakers and make a "sound wall".

Welcome to my faithful Marantz PRO PM4400

 

 Once again, I turn to Marantz this time seeking power and precision.
This beast is directly driving:

 The Mission 773 pair and the Celestion Impact s1 10"sub

The Missions will be talked about soon enought, so let's look at the celestion! This 10" driver with it's own poweramp and XOver, is able of going below 30Hz (normally you would go for a 12" and more to run below 30hz). we can;t however forget that celestion is the brand behing most rock concerts speakers, the bass stations on most dance clubs and, last but not least, a major builder and suplier of drivers for other speaker manufacturers.
Yes, their driver can go bellow 30Hz and still be able to go up to 150Hz because of the stiff and light construction.

 But we are not done with the Marantz PM4400 yet.... out of the back of the Celestion, Xover to 150Hz and up, there are a couple of Mission 772 on a pair of ATACAMA stands.

 Now lets look at the speakers that the Denon drives directly:
Starting with the back (since we where already there), a pair of Mission 774

 On the Middle we have a pair of very powerfull and robust Wharfedale XARUS 4000:

The finally, the best sounding speakers for the money ever built, driven direclty by the Denon on the front R+L channels, a pair of Mission 782.
These are very peculiar speakers that have a very interesting history, please read all about it here.

We can't forget that the mid-to low bass is output by a KEF 1000.2

 

 The result? please have some pictures:

 

This is a Video of the Sound quality and image, with "The Verve's - Happy Man" brutal guitar:

Here, it is clear that the camera mic is on the limit with just a simple guitar playing as -20db, and when I up to -10db is just distorts the pickup sound. But believe-me... the listening experience is flawless if you have ears instead of a cheap MIC.



And this is a video demonstrating how easy this handles pure bass, at volume, without distortion or brittleness:

Without surprise, the Mic is not able to perform at -20db with a bass full music, the 10db is just pure distortion on the MIC.

However, looking at the graphs several conclusions can be taken on both videos:

1. The system is reproducing at 24hz frequency and performs all the way up to 20khz without gaps
2. When the volume is increased, the system increases db's without compromising the frequencies... they all grow proportionally.
3. The Bass (hard to equalize) is maintaining the volume without gaining HUMMMMsss or becoming excessive.
4. The volume at -20db is enough to overwhelm a Splash Action cam's mic...with rock!
5. The 772 and 773 speakers are operating near the limit on the -10db with bass sound, I'll try to attenuate this in the future, so i can go all the way up to 0db and eventually end up without windows in my place :)

Now about the Missions... all the 772, 773, 774, 782... together with my M73i,  V62 and the Mission built Denon SCM51.

Some would ask, do you have a mission fetish?
No! I have an engineering over economics fetish... that's why.
It's easy to grab the best materials out there and, not minding cost, build a decent speaker that the client would buy for gazillion euro and perform nicely!

Mission is that brand that (in the old days) invested a lot of engineering time trying to create a speaker design that performed the best, and then try to replicate that design with materials that would cost less, so the client would not need to overpay (sometimes this came back to bite them, but some years in and a small research can turn this around in your favour... see my Mission 782 article).
The result is that most OLD missions sound better than their price range. But every now and then they build a product that rockets out of their standard into stratospheric performance.
The 782 is an example of that! It sounds better than speakers costing 10 times as much. Much like the M73i and V62 (after properly sanded with a minimum 2kg of sand) can sound better than speakers that cost 4 to 5 times as much.
The 772, 773 and 774 are a family of speakers that are excellent performers for the price... but within this family, the 774 is the excel. It just sings through the entire frequency range without a fuss.... it's far better than the cost.

Why? Well, just like B&W has John Bowers, Marantz has Ken Ishiwata, Mission had Peter Comeau.
Most speaker I buy are designs produced by or supervised by Peter Comeau. We seem to like the same things and that is very good... plus I love the idea of not paying for others laziness (nor marketing... hence not owning a single Bang&Olufsen).


Hope you like this article... more will follow are there are 5 other audio systems that make me very happy and proud... and will make their way into the next 5 articles, so stay tuned.

Mission 772 speaker repair

I recently brought a pair of Mission 772 speakers. They are old but they are gold. And they sit just perfect together with my set of Mission 782. 

The problem is that age takes the toll on these babies, and the rubber from the speaker outer damper started to degrade.

One of the speakers shown a fatigue fracture... not only not good and with influence over sound quality (when operating and high levels), being this an open center design, this would mean unbalancing and, in time, total driver failure due to the coil rubbing the walls and erode till destruction.

A solution was needed, and I would not let these babies go because of a minor problem. So ebay to the rescue and, soon enough, a repair pack was underway.

Ok then, ready, set, go...
First step is to lay down the speaker and remove the screws.

Then use a small knife to start to unglue/separate the external border of the old bubber/foam damper. BE CAREFUL when pulling as the inner side is still glued in and too much lift will damage the speaker cone.

Then work on the inside, following the same rule: no excessive lift.

Here is an image of the removed cone and the damage on the rubber damper.

It's an excellent time to inspect the main damper spring inside the driver showing in yellow. This one was just perfect.

As materials evolved, so did the design. You can compare the thickness of the rubber vs the replacement foam damper.
This is good news and bad news at the same time: good because less weight and the same tenacity will mean less moving weight and a better response....the bad news is that the heavier rubber would hold the cone I place better during centering and reassembly...so more work for me.

The glue. The glue is another problem:
You want enough blue to hold this in place...but not too much as is will add weight... and just enough to glue fast, but not too fast so you can move and place the damper properly and within geometry.

So the solution I to apply only to the inside, and  apply an almost transparent amount of glue on both the edge of the cone and the edge of the foam damper.

Then you marry the 2 parts together and, while HOLDING the cone with one finger, lift and place the foam on the cone...this will enable the glue to catch some air and react a little faster.

The material will try to counter the glue and the more surface you glue in, the more it will fight back.. SO, my recommendation is to grab gum tape, twist it into a rounded surface that will match the cone surface... and start fixing it in a cross pattern (top, bottom, side, side).

This is the final LOOK :)

Allow it to glue in... time for coffee, and a movie or two. I let the glue set in for half a day... it's not really a contact glue (rather looks like wood glue, actually). So it does take some time to set properly.

50% through... not it's time for the outer part.

The outer part is A LOT simpler... but not linear. 

Glue wise, just slightly lift the foam and pass the glue without worrying too much about the amount of glue... it's a fixed part so no weight to influence motion.

HOWEVER, this is an open cone design.. it is set this way to allow better movement on the cone and consequently a better response, but this means that there is also some fluctuation of the cone and the entire coil assembly. IF that fluctuation means the coil rubs the side of the wall containing the magnet, it will rub the varnish out and then short circuit the coil... and eventually just completely wear it out until it looses continuity.

So after you set the glue on the outside, and before it sets, just move the come up and down, while adjusting the damper outside. You will feel free movement, or a slight vibration, created by the coil rubbing the walls.

Again, you can have gum-tape (this time a simple cross is enough), and adjust until movement is free, I do recommend you bias the setting a bit towards the upper side of the speaker, so that when standing, the small but existing weight will auto-balance.

Again the glue set in... a day should be enough. And then screw the driver back in... connect your speaker and... well it's a speaker, you know what to do with it :)

This is the final look of the 2 speakers:
on the left you have the repaired one, the original (yet to be repaired) is on the right.

The speakers sound better with the new damper. Weight does influence moving parts... inertia, you know?