Budget Friendly Bookshelfs "T-M-M" with Amplifier

[sadik]

I have taken over a Project for budget friendly bookshelf with separate amplifier. Since this is a budget friendly project no exotic components will be used. The bookshelf will be in "T-M-M" configuration. The Mid bass woofers are from "SONY" and a tweeter, this tweeter was from set of Blaupunkt component speakers which I got from a car accessories shop. One of his customer took just the speakers. He didn't wanted the tweeters so he left it there, I was lucky to get them. Crossovers will be designed by our FM @Aniket

This speakers are for one on my friend who is not so audiophile guy and doesn't care for the aesthetics. The complete cost of this project including amplifier should not exceed 20K, it's but oblivious that I will not be considering my labor charges to keep it within budget.

Budget allocation is as under.
Mid Bass Speakers : Rs. 1,400/- for 4 Nos
MDF Sheet : Rs. 1,200/- (Only half sheet was used as the speakers were small)
Tweeters : FOC
Glue, Color, Mounting hardware, crossover components and other accessories : Rs. 6,000/- max

Amplifier Module 100 + 100 Watts : Rs 1500/- for both.
Transformer and Power Supply Bank : Rs. 4000/-
Enclosure : FOC (He has his own sheet-metal shop so he will supply it)
RCA & other Hardware : Rs. 2000/- (Allocated)

This is the main budget for now. There may be some missing items which I will need to cover up in balance amount.

Today I started the project, So lets begin with some update of my tools collection. This tool was one of my dream. My recent purchase is table saw 'DEWALT DWE7492", This is one of the best table saw and good value for money. However this table saw dose not comes with cutting blade. I have purchased blade separately which is from "MAKITA" having 32 Teeth for fast cutting. I have also purchase 60 teeth Blade which is from "Bosch" for smoother cuts but it cuts little slow.

It is necessary to adjust the blade & table fence parallel to each other, After watching some videos on you-tube i was able to set it very accurate within 0.02mm (used a dial gauge for setting which has 100 divisions for 1 mm). I also set the riving knife accordingly by watching videos on you-tube. Now I was ready to cut some wood so lets start with the project.

Sharing some Photos of my table saw & today's work. Below is me with my new table saw.

In the extreme right of below photo the cut pieces can be seen. Those pieces were already cut at my friends shop, he owns Makita table saw.

In below photo i have attached the safety attachment provided to cover the blade. This is very good safety feature.


Today I did the 45 deg cut on the edges of already cut pieces. What an accuracy of this machine. I am already in love with this tool.



I will keep on updating. In next post I will post photos of Amplifier module, Right now i don't have it in my cellphone.

 

[Lionx]

That's a cool toy you got there brother, really envious about your tool collection.

 

[sadik]

Update.

Today I completed almost 50% of the enclosure work. Below are some photos.

First I am sharing the photo of the amplifier module. The amp module is made by Lumin.


I have used Plate joiner for all the joints see the slots of biscuit in below photo. This biscuit slots helps both pieces to stay in place during clamping.

Some more assembly photos.


After removing clamps

The Back will be removable, In below photo the frame can be seen. The drivers will be mounted from inside hence the back baffle is removable.

I am thinking to change my plans a little bit, for front i am thinking to use teak wood.

 

[MaSh]

Wow @sadik, this is brilliant. Eagerly waiting to see how this budget build comes out.

Where did you get the amp boards and what were the other options you were considering?

MaSh

 

[sadik]

Wow @sadik, this is brilliant. Eagerly waiting to see how this budget build comes out.

Where did you get the amp boards and what were the other options you were considering?

MaSh

The Amp Boards I got from a friend he purchased them from Lumin. The other option I had mentioned already. I was thinking to make the front baffle from teak wood... just for better aesthetics. I am also sharing the photo of amp module from bottom, this is dual layer PCB

 

[sadik]

Update.
Finished gluing front face of the enclosure.

 

[MaSh]

Update.
Finished gluing front face of the enclosure.
View attachment 55673

Wow looking really neat. Any chance of building a Sub to go with this setup?

MaSh

 

[Thirumalkumaran]

Table saw is a really great tool definitely worth the 45 50k invested. Once setup.correctly for 90deg and parallel fencing, it's just cut and shut..! No jointer work or post trimming needed. Major issue is it needs dedicated space and regular truing.
Try getting calibrated brass bars and extended slides.. helps a lot. BTW, be very, very cautious about the fingers.
Get push blocks and sticks.

 

[sadik]

Wow looking really neat. Any chance of building a Sub to go with this setup?

MaSh

This project is really on very tight budget. So as for now there is no plan for Sub.

Table saw is a really great tool definitely worth the 45 50k invested. Once setup.correctly for 90deg and parallel fencing, it's just cut and shut..! No jointer work or post trimming needed. Major issue is it needs dedicated space and regular truing.
Try getting calibrated brass bars and extended slides.. helps a lot. BTW, be very, very cautious about the fingers.
Get push blocks and sticks.

This was one of my dream tool. By profession I an mechanical engineer. I own a mechanical shop so i have some serious measuring instruments like Vernier, micrometer, dial gauge etc. With help of this tools i have done calibration of my table saw. The blade and fence parallelness is within 0.02mm, this is more than enough for any carpenters requirement.

 

[SKR]

Update.
Finished gluing front face of the enclosure.
View attachment 55673View attachment 55674View attachment 55675

It’s a perfect professional job. Well done. Can compete with any speaker in cabinet work at least

 

[Thirumalkumaran]

This project is really on very tight budget. So as for now there is no plan for Sub.

This was one of my dream tool. By profession I an mechanical engineer. I own a mechanical shop so i have some serious measuring instruments like Vernier, micrometer, dial gauge etc. With help of this tools i have done calibration of my table saw. The blade and fence parallelness is within 0.02mm, this is more than enough for any carpenters requirement.

That explains the tight fits and flush trims. I'm an aerospace machinist myself and the techniques I use (Just by hand) still makes it a very close and precise fit. the disadvantage is it takes more time than usual, but well worth it. proper calibrated machines will reduce the time and increases teh repeatability.

 

[sadik]

Update
Today I did the hole for vent. The hole required is 89 mm. I have made my personal circle cutting jig which can be attached to my Makita and Bosch routers.

I am using PVC pipe as a vent. The Inner diameter is 77 mm

Below is my circle Jig. I have done the drawings and got it made on CNC laser cutting machine.

The Pivot hole


The Pin (Its 3.2 mm drill bit), I Made a initial small deep cut to check the size, first i inserted the pin in 88 mm to see the fitment. double marking can be seen of the it in the inside diameter of circle, that is 88 mm, so then I inserted the pin in 89 mm & checked the size, it was perfect 89 mm.


Checking the Vent fitment.

The Final Result

 

[MaSh]

Fantastic workmanship Sadik.

MaSh

 

[Bizi05]

Superb Sadik bhai

 

[sadik]

Fantastic workmanship Sadik.

MaSh

Superb Sadik bhai

Thankyou Friends here is todays update, Checked the driver fitment, and its a perfect fit

I have also made roundover on the vent which can be seen in above pics.

Below is the inside view

 

[oldmonk]

Hi

If the speakers are flush with the baffle it might be better

To my eyes the drivers appear to be sunk inside the baffle..

Just an observation

 

[sadik]

Hi

If the speakers are flush with the baffle it might be better

To my eyes the drivers appear to be sunk inside the baffle..

Just an observation

Yes flushed speakers would look better, but the frame is not that good for its display, it will kill overall aesthetics. Secondly these speakers are budget speakers so I have to compensate on something.

I did not understand by the word sunk. If you mean to say the surround may be rubbing against the baffle while moving front and back. then its not like that. There is no friction between surround and front baffle. There is an overall clearance of 1 mm between the surround and baffle.

 

[oldmonk]

I think it will be better for all drivers to be flush mounted to the front baffle ( and not any deeper ) in order to get better dispersion.

Aesthetics gets 2nd preference over sound unless the master orders otherwise..

However..In this situation you are the best judge...

 

[[email protected]]

Wow, looks awesome brother.

 

[Thirumalkumaran]

A really good job sir..
As others have mentioned rear baffle mounted drivers not only have aesthetic issue, but also phase and timing issues with tweeter (as the car tweeters would be mounted Front baffle), If the crossover has addressed, its great, but doubt due to the budget nature.

You can try what KEF does by seating the drivers in a counterbore and use a covering ring to close the gap.

eg.

(FYI, most expensive speakers are using cheap frames and just hide them)

All the best