DIY wire connection, diy interconnect

http://www.vandenhul.com/userfiles/docs/Audio_and_Video_Cable+Connector_Wiring_Diagrams_for_DIY_purposes.pdf


I always keep this in handy.Don't blame the cable if it is not sound good, it  might your connection technique that went wrong



KLau

Family war, JBL 4312d vs 4412a-updated

Update:Thanks Aki for the nice video

http://www.youtube.com/watch?v=sTVO4_igGwE&feature=related

Testing JBL 4312D

http://www.youtube.com/watch?v=pvAwBrYFWog

Testing 4412a.

You can see my toe. ha!

Last week was a shootout between 2 pairs of JBL. Many especially Mr.Chan from HK says  that the 4312D is the entry level before anyone decided to go for bigger JBL in the future.

When comparing with the 4412a .Both are 3 ways using 12 inch as the woofer but visually the 4312D woofer is white cone and the 4412a is black cone.There is no mid and high gain control for the 4412a.
This JBL 4312d is still new and it might not even run in.


First the JBL 4312d is being put up. The JBL 4312D had a high and mid gain control at the front panel. The owner set it at around 3(there is 1 till 10) on both high and mid. After listen for while I ask for permission to fiddle on the gain. “Please go ahead” is the answer and.i settle it 4 on the mid and 6 on the high

A Music Angel 845 is one of the amplifier that serve as the main amplifier.

Sound wise I feel the 4312d have a much better resolution on the mid and low. High I feel the woofer of the 4312d is the one that contribute much to the overall speaker sound.(Later i found out that the woofer cross very high that almost run it like a full range.) 

The 4412a is much smoother performer with extended high. This is a easy speaker for any amplifier. The presentation of the speaker seems to rounded up the many of the music.
 This 4412a seems to be using a much better tweeter.

I tends to like the JBL 4312D but the JBL 4412a seems to be the easier speaker.
The choice is yours.

KLau
*Thanks AKI from Sandakan for the above picture

Manger test disc

Sorry guys for didn’t update for such a long period of time. As expected Koo come over to visit and i have to thanks Koo for helping me to get the Mangers CD. (This happen before 2010 chinese new year)

This is a superb recording. I come to know manger through the single driver.(Last few year I am crazy about single driver and just miss out to own a manger driver)

This cd is a compilation of different genre of songs like light jazz, light pop, classicals, vocals, piano and a little bit of everything. Track 2 is good for testing imaging and my favourite is track 15 and it is good to test a system dynamic.


KLau

SAT bass trap 2- diy bass trap

Update SAT bass trap

Somkeone ask me why you use 6 ply of carpet instead of 5,7 or 8 ply. Good question,actually it need a mass of 1.49kg/m2.
Here is the calculation:
The panel surface

1.74 x 0.29 = 0.5046 m2,
1.49 x 0.5046 = 0.75kg



I have weight 1 ply of carpet is around 145gram(less10% to minus the excess)=130.5 gram

So 750 gram/130.5 = 5.74 ply,
So round it up around 6 ply.

I have try out 3 ply carpet at first and it is not working.6 ply give me more satisfactory result. Sometimes we really need to do calculation to cut down the trial and error.
On the 1st version i can varying the depth of the bass absorber panel.
I found that the result is close what i have calculated out.

KLau

SAT bass trap-diy bass trap

Simple as this (SAT)  baSS trap

Last year Koo come and visit me and taught me how nasty my room acoustic is. There is a lot of boom. Last week Koo inform me that he will be coming soon. So during this year I have employ 9 pieces of Helmholtz and 3 panel of bass absorber.The helmholtz will take care of the 120hz and below.

I only manage to finish the last piece of panel absorber last week. Before I make this last pieces of panel actually I have make another 2 pieces bass panel that can be adjustable. This is the simpler version.
The targeted frequency is 148hz.
The dimension of the panel is 174.38cm x 29.14cm x 11cm (internal)
1.49 kg/m2 panel mass.

This is the frame.I just use a few pieces of salvage wood.

After much consideration, i use carpet.The type of carpet we call in punch needle carpet.Rock wool is the best material but beware it may cause rashes.

I use 6 layer.I use staple .Now is 5 layer and later wrap the whole panel with another layer.If you worry the carpet is not strong enough you can put in wire mesh.But 6 layer of carpet might even put off a bullet.

This is the rear side.Just cover with a thin layer of plywood and done!

This is the 1st version oif panel absorber.This design is much more complicated with adjustable depth.

What is the result?

Before I employ any panel absorber, I can detect mid bass boom. At first I put 2 pieces, boom is disappear but there is mid coloration especially male voices. It is easily detectable when playing the Amos lee album.

When I added the 3rd panel the low mid coloration, high and dynamic is gone. So one must take care when we added something to our room it might disturb the whole acoustic sound balance of the room. We must be very careful when doing absorber for frequency more than 100hz. The range of the absorber range is too big and it might hinder the dynamic of a system
Koo, you can come now..

KLau

Jadis Pre

A Jadis jp80mc is having some problem and open up for health check. I took the opportunity to take some photo. The jadis jp80mc is separate into power supply and line.Show here is the power supply.This power supply is said universal to Jadis other pre amp like the JPS2.

KLau

What are you talking about

Many people talking about mid bass, mid high and etc but are they referring the same frequency that they are talking about?

To cut the confusion, here is the refer frequency range:

KLau