The problem of sound-absorbing cotton in the subwoofer box
Source: | Author:beauty-100 | Published time: 2018-10-12 | 3341 Views | Share:

Generally 12 inch horn volume in 30 to 40 liters is more reasonable, but mainly to look at the horn QTS (Q value) to determine. Volume of sound box
The formula is based on the fact that there is no filler in the box, or that glass wool no more than one inch thick is laid on each side of the speaker as standing wave.
Damping effect. Theoretically, the correct speaker design can achieve its design goal without needing to be dealt with separately. But in the real world, speakers
This technique of inserting absorber cotton inside is very useful because it can achieve a specific speaker size and Q value, thereby changing the speaker response, in addition
There is no other way. In addition to the ability to substantially suppress the sound-dyeing problems caused by reflection in the speaker (see Section 4 of this Chapter), the sound-absorbing cotton is added to the speaker.
It will also affect the following parameters:

1. damping loss
It is easy to cause friction loss if the overstuffed sound-absorbing cotton is close to the monomer frame. According to Loudspeaker Design Cookbook
Test the frequency response of the different sound-absorbing cotton volume. For example, the filling volume of 50% is not obvious for the standing wave inside the speaker.
To strengthen the sound absorption effect, generally should adopt high density sound absorbent cotton. And the filling volume of 100% will obviously improve the standing wave of speakers, while two different materials.
This phenomenon can also be seen in the combination of absorptive cotton and 50/50. To sum up, from the perspective of the characteristics of car audio, in order to use the smaller box and make the box body
The standing wave is reduced to a minimum, and 100% of absorbent cotton is a good choice.

2. flexibility increases
The use of low-density, specific heat-resistant materials (glass fibers, Dacron synthetic fibers and long fibers, wool, cotton) improves the sound compliance of speakers
In theory, the volume of the speaker can be increased by up to 40%, and in practice, the equivalent volume can be increased by about 15% - 25%.

3. efficiency increase
Choosing the right amount of filling, material type, and location in the speaker box can increase efficiency by as much as 15%.

4. Mass change filling with absorbent cotton will change the total mass removable in the system. This phenomenon is generally considered and limited.
The air movement on the back of the unit is related. Increasing effective mass will reduce efficiency, but not as a result of compliance.
The increase in efficiency is much greater. Because we do not want to reduce efficiency, there are two ways to limit this effect.
Ringing. The first one was used by Advent company, plus the support frame at the rear of the bassoon unit to separate the absorbent cotton. Second
It is the use of uncompressed and less dense than sound-absorbing cotton, directly affixed to the unit after the basin rack, as a density.
A high absorber between sound-absorbing cotton and monomer.