Cabinet build LS-Encore kt & SUB12B-SA12

[naveenkumar]

Hi,
Just completed the 90% of cabinet build and here are few pics

Stuffing the cabinet with Foam Sheet

After the stuffing the foam sheet, was curious to see the performance of the sub woofer and LS-Encore.
Due to unavailability of amplifier or AVR, I have connected the speaker to the Philips multimedia 5.1 speaker system DSP 3000 and direct connection to the subwoofer from the DVD player (OPPO 980H).
Sounded very harsh, not crispy and low bass effect, dont know probably that could be because of improper amplification.
Now coming to the Subwoofer, Initially connected DVD players subwoofer out to LEF in the plate amp, it sounded very boomy and loudly. As Dannys suggested connected to Left input, volume level was very low and had to keep the volume full to get good level of bass.
Played few MP3s with the Variable bit rate, bass level was good but had vibration,
Played DTS 5.1 movie, speakers sounded same whereas sub level was very low and no bass effect at all.
This is how sub is connected

As mentioned earlier in another thread, still I feel the hotness in the plate amp within 5-10 mins, heat is bearable and I can keep my hand for some time. I stopped the amp after 20 mins to avoid malfunctions
I have checked and cable polarities are correct.
Here the picture of Plate amp circuit board and could see the black mark. Dont know is that the cause for the heat.

Someone please help me in fine tuning the speaker / Subwoofer and plate amp heat issue

Thanks / Naveen

 

[Rgn1]

Hi Naveen,

Thanks for the pictures . Looking good .
Just wanted to ask you if you changed the cabinet build design for the XLS Encore?

Cheers!

 

[naveenkumar]

Hi Rgn1,

Have increased height to 5 inch to look like mini floor stand and other specs are remains same...

 

[captrajesh]

Have increased height to 5 inch to look like mini floor stand and other specs are remains same...

No wonder it is not sounding great. Speaker designing is a serious business and cannot be done on one's whims and fancies.

 

[omishra]

What kind of foam sheet is this? It looks likes closed cell foam from the pics. This will severely damage internals of box in terms of volume and internal reflection.

No wonder it is not sounding great. Speaker designing is a serious business and cannot be done on one's whims and fancies.

Agree!

 

[naveenkumar]

Hi CAPT, omishra

Many thanks for your valuable comments....

No wonder it is not sounding great. Speaker designing is a serious business and cannot be done on one's whims and fancies.

Let me try to add piece just 4 inch above from the bottom panel to cover and see how its sounding...

What kind of foam sheet is this? It looks likes closed cell foam from the pics. This will severely damage internals of box in terms of volume and internal reflection.

Foam sheet is similar to the packing of plate amp which had sent by Danny.

Top view

Side view

Have seen this kind of damping in one of forum (Pictures of Selah designed Tempesta Extreme and RC4 (no subwoofer) ), so thought of doing it same. if this is not advisable, let me know some kind of damping material which can be available at the affordable price.

 

[captrajesh]

Let me try to add piece just 4 inch above from the bottom panel to cover and see how its sounding.

I'm not sure how much would that help.

Foam sheet is similar to the packing of plate amp which had sent by Danny.

Top view

if this is not advisable, let me know some kind of damping material which can be available at the affordable price.

I tend to agree with what Mishraji states. You would've been better off using the design drawing provided by Danny. For damping, you could've used bitumen sheets and for arresting the standing waves, best was to use fibre glass sheets or at least egg crate foam sheets or polyfill.

 

[jls001]

That's Hitlon packing foam. No good as acoustic damping material.

 

[sbg]

naveenkumar,

bitumen sheets are available with hardware shops( last I checked with vendors near my home, suggested yeshwantpura and also in SP road). Polyfill ( you can use the one used in Pillows ) are available in Chickpet/cottopet area near Majestic - it goes about 140/- to 180/- per kg. flat sheets are also available but a bit expensive.

 

[omishra]

After the stuffing the foam sheet, was curious to see the performance of the sub woofer and LS-Encore.
Due to unavailability of amplifier or AVR, I have connected the speaker to the Philips multimedia 5.1 speaker system DSP 3000 and direct connection to the subwoofer from the DVD player (OPPO 980H).
Sounded very harsh, not crispy and low bass effect, dont know probably that could be because of improper amplification.

Looking at above picture it looks like you have tested speakers in half cooked condition. I mean back panel yet to be fixed and for time being tied with lace.

Remember your cabinet must be air tight and internals non reflecting for audio waves.

I got exactly opposite results of the build. It has good bass and its mellow HF, not harsh. In fact it is more flat response. It's here.

 

[naveenkumar]

Thanks Om and your build looking too good.

Yes, you are correct and its cooked half way through.

Based on advise from you & Capt, got changed the closed foam. now the cabinet contains 2 mm tar sheet (Not able to find bitumen sheet as sellers not even heard that name), 1 inch thickness of PU foam and 1 inch thickness of Poly fill sheet. indeed effect has changed really a lot and HF level more than what I expected. bass level is moderate and now looking for change in amplification part.

Thanks once again for your comments......

 

[Rgn1]

Thanks Om and your build looking too good.

Yes, you are correct and its cooked half way through.

Based on advise from you & Capt, got changed the closed foam. now the cabinet contains 2 mm tar sheet (Not able to find bitumen sheet as sellers not even heard that name), 1 inch thickness of PU foam and 1 inch thickness of Poly fill sheet. indeed effect has changed really a lot and HF level more than what I expected. bass level is moderate and now looking for change in amplification part.

Thanks once again for your comments......

Hi Naveen,

Good to know it has improved . I think tar sheets and bitumen sheets are one and the same. By the way did you also modify your cabinets to the original dimensions?

Cheers!

 

[omishra]

Cabinet acts same like damping in shock absorber of car. It provides smooth cushening for cone-air movement, but same time stop extra oscillations. Also air volume and port are designed to provide maximum LF extension for that particular driver. So there must not be internal wave generation by means of internal reflections or panel vibrations. That tampers air moved by driver cone.

Also if you are pushing to car and you feet are unstable on ground then you will slip, but car won't move as insufficient force applied. Same way if panel vibrates or cabinet moves then air moved by cone is not the same by desired electrical signal. Because diaframe is unstable and attached cone can not move same air.

You need to take care of cabinet accordingly. That's why cabinet building is also important because it works along with driver and connected crossover to produced designed frequency response.

 

[captrajesh]

The bitumen (tar in Hindi) sheet is affixed onto the panels to dampen it to prevent it from resonating which would colour (add it's own unwanted noise) the sound. Bracing is done to reduce the cross section of the cabinet walls as larger the panels, greater would be the resonances.

Now coming to internal reflections, (standing waves) they affect the backward movement of the woofer cone which adversely affects the sound quality. This doesn't affect the functioning of a tweeter because they are sealed from behind. (by and large; there could be exceptions)

 

[captrajesh]

Continuing the previous post which I realised was incomplete.

The standing waves are generated by the sound produced by the back wave of the woofer cone which get amplified by multiple internal reflections; they are reduced by way of absorption using fibreglass/ foam/ polyfill which are listed in descending order of their efficiency levels.

 

[naveenkumar]

Om & Capt,

Much informative and very well explained.

 

[jls001]

@Capt: have you started your build yet?

 

[captrajesh]

@Capt: have you started your build yet?

My work related activities are keeping me so busy that I've not focusing enough energies on the build.

I had finally been able to catch up with that elusive carpenter who makes speakers for Torvin. He also proved to be exorbitant. He has quoted a figure of 33k for the boxes for X-SLS (front towers), X-CS (centre), A/V 1RS (rears) and the Servo subwoofer that too with laminate finish.

Obviously, I have to look elsewhere.