How to increase body Saba without resizing.

The word "fiber" is firmly entrenched in our life we meet in various aspects, from fiber optic cables entangled the whole world, to exotic meals in expensive restaurants when food grinded to the state of the fibers. But for a powerful Boxing-builders, the term "fiber" means primarily the magic ingredient*, able to help achieve maximum bass from minimum sizes**.

*(We are talking about fiber cotton-Dacron-polyester. What is difficult to understand, but I found some similarity. This the material is called in the vernacular "batting" and is used as the liner in clothing and padding of furniture. And we are talking about wool, not about sheet batting, although the latter is sold in any fabric store and can be used if it is slightly fluff).

**(Although for me, the term "fiber" in the first place means MDF, or, speaking in Russian LWП - fiberboard. I very convenient from the pits sculpting. Can't immediately do not share their observation - MDF is very hygroscopic and most importantly - breathable! Let a little, but misses. I advise you to impregnate her some stuff, for example linseed oil).

There is no secret why the use of fiber filler used successfully by experienced installers for many years. Take two identical box, insert them in a completely same speakers, complete one of them, and you witness what filled the box gives a much more convincing low bass. Simply put, the filler is cheating speaker, causing him to believe that he is in box larger by volume than it actually is. And the bigger the box, the lower frequencies it can reproduce.

Filling the box - alternative for those who do not want to give plenty of space for a subwoofer box. Another similar alternative is Isobaric design, which employs a pair of speakers. The disadvantage of Isobaric is considered a more complex design, the need buy two speakers instead of one, and loss of sensation almost 6 dB, since the mass of the moving system is doubled. True the latter, usually compensated parallel speakers.

The physical part of the work of the filler inside the Cabinet not less than interesting: the Air inside the Cabinet when work gets very hot and dynamics it becomes harder*. When the inner space of the box is filled fiber wool, stirring fiber dissipate heat, creating for dynamics visibility Boxing larger.

Theoretically, the filling of Boxing can give virtual increase the volume to 40% of actual size. Simply put if you have the boxes with a volume of 20 liters, and when properly filled, from the point of view dynamics it will look like the box is the size of 28 liters.

*(Distinguish heat from air compression and heat from allocated coil of heat in some of the sources of evidence the temperature increase of two degrees for every 10W of power. Obviously under the rigidity of the air author meant it to heat the extension, which, from the point of view of dynamics, the air " back" really becomes stiffer).

To date, the most commonly used three types filler: glass wool, just cotton and polyester cotton. Polyester wool is the best choice because it has small particles capable to damage the speaker or your skin as glass wool and is much cheaper than simple wool. You can buy it in the furniture Department of the nearest K-Mart or Home Depot or nearby furniture factory.

To measure the effectiveness of filling the author used the analyzer MLSSA and three test box - private cubicles 39 litres and 144 liters, and the bass reflex box 39 liters (port 7.5 cm diameter and 15 cm length) with different density. For closed boxes effective volume was determined by the resonant frequency of the system and the value of Qes. For bass reflex box was cranves the tuning frequency of the empty box frequency settings filled with the help of the program Speak for Windows, which allows to calculate the effective volume by difference resonances. In each case, the experimental results were more than promising: all three boxes have been received, the increase in the effective volume of 25 to 35 percent of the actual volume using the filling level from 16 to 28 grams aggregate per liter of internal volume.

Closed Boxing 39 litres

The density

(grams/liter )

The resonant frequency

(Fsb, Hz)

Effective

volume (liters)

The percentage

increase

0

56.6

39

--

8

53.0

45.3

14%

12

52.7

48

21%

24

51.7

51

29%

28

50.8

53.8

36%

41.6

50.4

45.3

14%

49.6

52.6

34

-14%

 

Closed box 144 liters

The density

(grams/liter)

The resonant frequency

(Fsb, Hz)

Effective

volume (liters)

The percentage

increase

0

42.0

144

--

4

42.0

144

0%

8

41.2

164

14%

12

40.3

175.5

22%

16

39.4

184

27%

20

38.6

184

27%

24

40.2

158.6

9%

 

Bass reflex box 39 litres

The density

(grams/liter)

The resonant frequency

(Fsb, Hz)

Effective

volume (liters)

The percentage

increase

0

42.0

39

--

6.4

39.1

45.3

14%

13.6

37.2

51

29%

20

35.2

53.8

36%

22.4

34.2

56.6

43%

28

35.2

53.8

36%

When you create a system on the basis of these data it should be borne in mind that Qes and therefore Qts closed boxes decreases. For bass reflex box decreases lower peak impedance, and the upper peak shifting slightly lower in frequency. Also found another interesting effect - with the increase of density of filling in the resonant frequency of the system again begins to rise. The reason for this is the fact that the fibers lie so tightly that it can't move and effectively distribute the heat.

It should also be noted that the filling is less effective in boxes of large size.

The moral is: the larger the box, the harder it is to cheat speaker.

Some useful patterns:

Fill a small boxes - up to 85 liters, with a density of 24 grams per liter of volume and you will receive 30% increase in volume without any serious side effects. For large boxes filling should be about 16 grams/liter and the increase will be about 25%. IT'S THE REAL TRUTH!!!!!!!!! I'm not once checked in practice, the data volume of the body actually increases by 30%.

After the housing Assembly useful volume calculated (not forgetting subtract the volume of the speaker and timber) it needs to be at least 3 l more than the indicated program.

Then again employ the imagination not forgetting the purse and issued SAB outside.

To any Sabu need a decent power amp and the low pass filter.

When the preparation of the manuscript partially used materials Tatiana G. R.

Author: Kostya, This email address is being protected from spambots. You must have JavaScript enabled to view it. ; Publication: www.radiokot.ru, www.cxem.net

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