» Electronics » Sound and Acoustics »We collect hi-fi MEDIA CENTER from old speakers

We assemble hi-fi MEDIA CENTER from old acoustics

Electronics / Sound and Acoustics

Added 22 commentary

Background:

On shelves with spare parts for electronics, 3 different computer speakers were gathering dust, with split cases and torn wires, but the amplifier boards and speakers were working.

The first amplifier (4w x2) had good sound at medium and especially high frequencies, as well as had a bass-treble tone control, and volume control.
The second amplifier (3w x2) it sounded great at medium frequencies, while it had a “stereo widening button” and volume control.
Third amplifier (15w SUB + 3w x2) was from a kit with a subwoofer and two tweeters giving out good bass, it also had a volume control.

For a long time I wanted to collect hi-fi MEDIA CENTER from all this “wealth” in a monoblock (not a “boombox”, with volume the main priority) with good sound quality, the heart of which would be bought (on the famous site of the Chinese brothers) "USB-Bluetooth-Radio module."

Used in work:
Laminated fiberboard 2100 × 150 (1 pc.)
Laminated fiberboard 2100 × 100 (1 pc.)
wood glue (preferably bone)
glue gun and glue to it
corners 15 × 15 (15 pcs)
3 × 5 screws
hairpins M6 × 100 (8 pcs)
end sleeves (nuts) M6 with a deaf cap under a hexagon (16 pieces)
power wires
speaker wires
signal wires
heat shrink tube (different)
soldering iron
wood crowns (diameter corresponds to the speakers) D67, D50, D30
thick cardboard tube for D30 / L60 bass reflexes (3pcs)
network cable + jack for it
telescopic antenna L150 / 400 (1 pc.)
LEDs (3pcs)
decorative handles, for potentiometers (resistors) (4pcs)
mortise door handle (for swing doors) L150 (1pc)
handles for the cabinet arc-shaped L130 (2pcs)
plastic support legs L20
MDF miter box and hacksaw
synthetic winterizer

step 1.
We model the layout in a 3D editor, draw a general scheme of work

We mark and cut off the blanks (reference dimensions, since each will have everything individually)
a) top, bottom = 600 × 150 (2pcs)
b) front, back = 584 × 100 (2pcs)
c) ends = 100 × 150 (2pcs)
d) bulkheads = 100 × 180 (2pcs)

step 2.
Marking holes for speakers
4w x2, 3w x2 - on the front (front) part of the body
15w SUB - on the bottom of the chassis
3w x2 - on the top cover of the case
Drill a hole with a crown
We process sandpaper
Mark and drill holes for screeds with studs

step 3.
We assemble the box, temporarily turning the corners, to fit the parts of the case
removing panels alternately - coat with wood glue and tighten with corners
In bulkheads, we make recesses for pulling wire harnesses
Glue the subwoofer bass reflex tube
We are waiting for the glue joints to completely dry, and we turn out the screws and remove the corners

step 4.
With a glue gun we pass all the seams (creating additional mechanical strength of the joints)
Trying on speakers

step 5.
Mark and drill the holes of the support legs (needed for the normal operation of the subwoofer speaker)
Glue the legs to the carpentry glue
We mark and drill a groove for the door handle, which performs the function of a niche, for placing the knobs ("twists") of potentiometers.
We mark and drill 4 holes in this handle to accommodate potentiometers.

step 6.
For perfect tuning of the sound field, it was decided to maintain the separate functioning of each amplifier, so there is a separate switch for each amplifier (as well as a “stereo expansion switch”)
We mark and drill holes for all switches, as well as a common network switch, on the rear panel.
Cut out the groove for the power cord jack.

Step 7
We begin to collect in a single whole electronic stuffing MEDIA center.
We set the switches in the upper deck, and the potentiometers in the prepared decorative knob.
We solder the LEDs, and place them in a suitable plastic part (I used a part of the fastening of a children's toy)
We connect the wires, marking the wires with paper tape and making marks on it with a marker (this is necessary, for example: to transfer acoustic wires if you mixed up the left and right speakers)
We solder the speakers, amplifier transformers - we fix on the bottom of the case.

Step 8
The first two amplifiers were fixed directly to the decorative handle, with potentiometer nuts.
Subwoofer Amplifier - was removed and fixed to the upper part of the housing cover.

At this point, a wonderful USB module from ChinaWhat it has: USB port, TF port, Radio, Bluetooth. power supply 5-12v
The location of the module was chosen on the front of the case.
We mark and drill a groove for it.

Step 9
Signal incoming channels of three amplifiers - connect in parallel to each other, and solder to a set of wires with a connector, "arrived" with the USB module
We fix the power supply for the USB module (I had it ready for 9v, but it can be ordered on"The same well-known site", together with the module)

We check all the connections and the correct location of the speakers and record a special track with separate sound on the flash drive.
On the bulkheads, in the grooves made, we fix the vibration-suppressing madeleine (through which the wiring harness will pass)
In the upper case cover - mark and screw the handles for carrying the MEDIA center.

Step 10
After listening to the “pre-assembled design”, I realized what I needed to add.
Two additional bass reflex tubes (in the left part of the case and the right) were marked and cut into the back of the case, as well as the subwoofer section was filled with syntepon. The sound after the operations became "crystal clear" and having a pronounced sub-bass color.

We tighten the body with studs, wipe it from dust.

Total
We enjoy high-quality sound, devoid of flaws, which can be adjusted to suit every taste and music genre
here you can see how it works

Thank you for reading about the end!

Added 22 commentary

22 commentary

Vladimir Spiridonov June 8, 2019 8:28 p.m. +1

Reply To quote A complaint

I made about the same media center, though later I pulled out a radio module and cut a window for a Chinese car radio 2 Din for 1800 rubles, the function is the same as that of the radio module, but the names of the tracks and artist are reflected. And if there is a desire, then a 2 Din android car radio can be delivered.

May 16, 2019 00:55 +1

Reply To quote A complaint

Made pretty, okuratnenko - well done. And at the expense of sound quality, the main thing is that you yourself like it!

April 15, 2019 20:58 +2

Reply To quote A complaint

Quote: Lexnett

do not compose! - at the beginning of the article it is written in black and white what is made of "shit and sticks"
/// On shelves with spare parts for electronics, 3 different computer speakers were gathering dust, with split cases and torn wires, but the amplifier boards and speakers were working. ///

1. This is your self-confession that Hi-Fi was not lying around.
2. The article itself does not say that the dimensions of the product are somehow related to the size of the original columns.

April 15, 2019 18:08 Author 0

Reply To quote A complaint

April 14, 2019 4:35 p.m. +1

Reply To quote A complaint

We are with Guest Alexey proceeded from the author’s claim that these are tweeters. Although, most likely, you are right and this is the midrange-tweeter. But in any case, these are speakers that do not reproduce bass.

April 14, 2019 2:51 p.m. +2

Reply To quote A complaint

Are you reading through the line? Or are the glasses sweating?

And you do not sweat rude brains? What dynamics is the bass reflex pipe designed for - HF, MF, or is it SB anyway?

(silent for the sound)

So after all, the sound is being discussed!

April 14, 2019 2:39 p.m. 0

Reply To quote A complaint

Tweeters I would put on the front panel

Have you met tweeters with soft suspension? Look at the photo!

April 14, 2019 01:42 AM +2

Reply To quote A complaint

Excuse me, master, we will not notice your strict instruction.

April 14, 2019 01:41 0

Reply To quote A complaint

He wrote this in the comments, in the article itself about this is not, hence the legitimate questions. You yourself would first read an article or something. ((

Guest Alex April 14, 2019 01:24 +1

Reply To quote A complaint

So he wrote that the dimensions of the gouged columns were taken as the basis, he just spreading the dimensions (in the middle the volume of the SB) all the shit combined in one case! Are you reading through the line? Or are the glasses sweating? What kind of professorial attacks? Chel shared the joy of a successful design (I am silent for the sound) - instead of practical advice, there is obsiralo!

April 14, 2019 01:17 AM Author 0

Reply To quote A complaint

all the best !, I wrote to you in a previous post

Guest Alex April 14, 2019 01:10 +2

Reply To quote A complaint

Yes, spit on all-take care of your health! HI-FI-not hi-hi, ha-not fay ... Intermodulation, coefficient. harmonics ... In the years 70-80-90, UZCH (ULF) soldered with parameters 0, 001%, and the men laughed, why the hell .. are you tormented? Where you will find “speakers” with such characteristics ... Yes, no where! But! The shitty amp, the shitty sound! Acoustics, too, was blotted out. At that time, the Monsters of Soviet Acoustics published practical and scientific articles in the Radio magazine, while we "dumb" read and reproduced ... I, too, have every good fortune to want to slap something in old age, but laziness overpowered, and looking at you, I slap another HI-FI !!! But already with active frequency filters. Good luck.

April 14, 2019 12:47 a.m. +1

Reply To quote A complaint

Quote: Lexnett

stereo balance switch (again do not read OH switch is NOT a regulator),

You wrote about SSR, not me! And you do not have a stereo balance switch, but a stereo expander switch. If you do not distinguish the regulator from the switch, and the stereo balance is from the stereo base, then there really is nothing to talk about with you. ((

about the slope of the frequency response - this is not for me, this is in your dissertation

About the slope - this is for you to independently study the principle of operation of the single-armed LF-HF regulators.

handles - for moving (device for the floor)

Are you going to drag him around the floor all the time? To put it on the floor once, pens are not needed.
I rated your product very highly, but its description is crumpled, incomplete and fragmentary in terms of electronics.

Guest Alex April 14, 2019 12:43 a.m. +2

Reply To quote A complaint

Lexnett, but do not listen to the "good words" Koi do not know how to cut, plan! But! I would bring the tweeters to the front panel, a couple of midrange speakers to the top, as Tweeters in many respects form the stereo effect and “suppress on obstacles”, which cannot be said about the bass sound, it is “written in the center.” Phase inverters are tuned to the acoustic design and resonant frequency of the speaker, since you took the old volume and the “pipes” old will go. Did you put the frequency separation filters on the DG, because without them, alas: broadband playback from all the DGs is not gut ... And, in general, you're done !!!

April 13, 2019 10:58 p.m. Author 0

Reply To quote A complaint

I will surprise you, but there was only one regulator in the old LF-HF columns (about the frequency response slope - this is not for me, this is for your dissertation)
A typo in the numbering of the amplifiers does not affect the assembly in any way (from the word - at all)
stereo balance switch (do not read it again; the ON switch is NOT a regulator), handles - for moving (device for the floor)
The rest with sofa experts, I will not even discuss this. you have 2000 comments and not a single homemade product, so
let's say goodbye to you

April 13, 2019 10:50 PM +2

Reply To quote A complaint

Quote: Lexnett

re-read carefully the article there everything is painted in detail

It’s your fantasy that everything is described in detail there.
1. Three power supplies are indicated on the block diagram, but nothing is said about them in the text.
2. Even if your product is on the floor, which you did not mention, all the same, the tweeters are directed to the ceiling.
3. You yourself would read what you have written: "First amplifier (4w x2) ... had a bass-treble tone control ... ". A typical tone control includes two potentiometers, there are also one-knob controls for tilting the frequency response, but it doesn't follow from the text that you have it like that. About RSB (you need understand - the stereo balance control?) in the article, not a word. And where did it come from if there are only 4 knobs? I’m not saying that adjusting the overall volume with the buttons on the Chinese module is not the best solution.
4. Perhaps I incomprehensibly wrote. ((I’ll clarify. What is the functionality of the handles for an arc-shaped cabinet?
5. "potentiometers - 3 volume controls 1 tone control (read the text more carefully)" - read for yourself: the text says only about what potentiometers were in the original amplifiers, moreover, the tone control is inaudible.
And about Hi-Fi, you yourself answered:

Is it not clear by the used Chinese module)

April 13, 2019 10:22 p.m. Author 0

Reply To quote A complaint

Instead of writing such a comment - read the article carefully there everything is painted in detail
Especially for you who do not read:
1) for this home-made product, “everything inside” of the former speakers was taken (I didn’t even delve into what kind of transformers the manufacturer set - the task was different to assemble NOT new - but to make from the existing one)
2) tweeters are located upstairs - since I personally have this “device” standing in a large open room with a minimal amount of furniture (photo studio) - on the floor.
3) the description says: tone control is available at amplifier No. 2. and the overall color of the sound, in addition to this control, is set by the volume of individual amplifiers and SSRs (read the text at last)
4) since the device is on the floor - the functionality of the handles is very justified
5) potentiometers - 3 volume controls 1 tone control (read the text more carefully)
Regarding HI-FI, I’ll repeat three times not the statement but the IDENTIFICATION of the difference BETTER in the general sounding from individual speakers (old) - which were used in the project.
the difference is FLEXY flexible enough tone setting for different genres
YouTube unfortunately can’t convey the sound quality, BUT due to the use of different ones (well, different frequencies, different sounds from amplifiers ...and I wrote about it above in the article) on the reproduced frequency by amplifiers and speakers (which were also taken from there) - the sound turned out GREAT (I have something to compare! I have "B&W monitor" on my computer)
What are you attached to this HI-FI?))) You also do not forget to write GOSTs and throw links to the designation)))
home-made was done without any claims to studio sounding, isn’t this clear from the used Chinese module)

April 13, 2019 9:26 p.m. +2

Reply To quote A complaint

Instead of blaming others for gallstone, they would write in the description where the sizes of the box and phase inverters are taken from. Then u Queen there would be no logical questions.
The product itself is made diligently, neatly, but do not call Hi-Fi what Hi-Fi is not.
Nothing is said about BP1, BP2, BP3 amplifiers. Tweeters are located on the top panel. There is no tone adjustment. The location of the handles on the top panel is not functional. It is not clear what the 4 potentiometers are.

April 13, 2019 8:42 p.m. Author +1

Reply To quote A complaint

I was always amused by "such" commentators)) good luck to you!
P / S Write more, splash out knowledge, but rather do something with your own hands and lay out

April 13, 2019 8:24 p.m. +2

Reply To quote A complaint

Why so much bile))? HIFI in this case designated highly quality sounding

And what do you mean by the concept

very high-quality sound

over the entire frequency range

Is it all over?

what standard can a non-factory thing be talked about?

But you are claiming HI-FI!

For amplifiers: Non-linearity of the frequency response in the range of reproducible frequencies 40–16000 Hz - 1.5 dB at the linear input (2 dB in the presence of a corrector);
The coefficient of nonlinear distortion in the range of reproducible frequencies is 40–12500 Hz, not more than 1%.
Intermodulation distortion coefficient in the frequency band of 250-8000 Hz (also outside this band when the sound pressure level is reduced by 6 dB), not more than - 3%; The spread of channel parameters in the range of reproduced frequencies, not more than - 3 dB;
For acoustic systems: The frequency response is non-linear with respect to the average sound pressure level in the reproducible frequency range of 100-4000 Hz, dB - ± 4 dB (+ 4 / -8 dB);
The coefficient of nonlinear distortion at reproducible frequencies of 250-1000 Hz (2000 Hz), not more than 3% (1%)

In order to draw any conclusions you need to hear

That's it! And also compare! Look for old audiophiles among your friends and listen to the real Hi-End!

deep knowledge of bass reflex diameters

In general, a bass reflex is calculated for specific heads in a specific acoustic design.

April 13, 2019 19:57 Author 0

Reply To quote A complaint

Why so much bile))? HI-FI in this case indicated a very high-quality sound - due to the use of independent amplifiers and adjustments over the entire frequency range. what standard can a non-factory thing be talked about?
The volume of acoustic boxes (height width and depth) was taken directly from the old crumbling and split acoustics. From there, the diameters and length of the phase inverters that were in it were taken (initially I did not want to put them)
From myself, I added only a synthetic winterizer to the subwoofer, which very well removed extraneous echoes from the boards and wires
That's it about the wires, I agree with you (but for this there are factory things).
In order to draw any conclusions you need to hear what happened in the end and not to trump standards and deep knowledge of the diameters of phase inverters.

April 13, 2019 19:40 +1

Reply To quote A complaint

Well, let it be fi!

The word “Hi-Fi” on sound-reproducing equipment means that it complies with one of the following standards: DIN 45500 or IEC 60581. DIN 45500 has been canceled by one part, the other has been replaced [1] by the European standard IEC 60581 [2], with minimal modifications repeated GOST 24388-88 (for amplifiers) and GOST 23262-88 (for speakers)

two tubes of phase inverters (in the left part of the case and the right one), as well as the subwoofer section is filled with syntepon

What considerations guided the author when choosing the number, diameters and lengths of tubes of phase inverters and placing them outside the subwoofer department? About catering and pooling entrances - another song!

We assemble hi-fi MEDIA CENTER from old acoustics

Add a comment

DIY categories