Well I do not know, I do not know that people find in all these booms and bams which take off from the boxes named subwoofers. However, I all the same have given in to a herd instinct, have caught this hysteria and have decided to hammer together to myself a subwoofer. It is a lot of walking on various sites and the forums devoted subs-making and in the general audio the technician, I have understood that concrete recommendations for choice a dynamic head and other components to me not to wait. How many people, are so much ears, it is so much and opinions., By the way, twice it is more than ears.
Well it is fine, it is necessary to do all most. We will plunge into a jungle subs-making, wood-making and other adjacent disciplines.
Well, to begin with about a dynamic head.
For LF-dynamics, and for a subwoofer especially, diffusor should be necessarily on rubber suspension and have as it is possible large a horizontal course. In key parametres it is necessary to pay attention to the maximum sound pressure created speaker and resonant frequency – the it more low, the better (well, to known limits, it is final). To put it briefly, after burdensome meditations and checks repeated, my choice has fallen to German company Visaton and their product GF-200 which they position, as Hi-End the decision.
In Moscow and Peter this head it is possible to buy the AV-CENTER in firm. At once I will tell – a thing not cheap, but also not that that great expensive. Full info about it dynamics can look on a site of the manufacturer – the reference above, and I here shortly will tell about it.
It is 8-inch speaker (20см) – small, with two coils on 4 Ohms, the maximum capacity – 180 watt, nominal – 120 watt. Watts fair, not the Chinese. Appearance though, and not the main thing, it is possible to look it on photos:
Next. It is necessary to select, what box we will hammer together.
Selection of the box
I cannot say that the selection is diverse, but to select there are from what – types of boxes the following:
- the closed box – [ZYA] – the simplest in the production under the household conditions type;
- phase inverter – more complex; however, in certain cases makes it possible to substantially improve sounding sub;
- [bandpass] – [BP] – the most complex and in the calculation, and in the production the box, however, of special advantages with exception of the fact that the dynamic loudspeaker hides inside the box and is not put out outside was not noticed.
Since on my nature, I man sufficiently lazy, was decided to stop at [ZYA]. Moreover in all forums, where me bore at the beginning of this epic about it they answered sufficiently well majority, one way or another had concerning it the matter. Further, we should calculate the dimensions of box. But you as thought – everything not so is simple, if we make this all in the science.
Calculating the box
The dimensions of box are counted on the basis of the value of the volume, necessary for dynamic head for the best working conditions. [Khm]… something I similar covered – itself did not understand. It is shorter, on it is necessary to make a box with this internal volume that the dynamic loudspeaker inside it would feel itself in the best way and it would thump from all its forces. How this to make? There is a heap of the programs, which make it possible to calculate different of types of boxes in the assigned parameters of dynamic heads. I used two – JBL Of speakershop and Speakerpro 6.0. Running in forward, it must say that both programs gave out identical results, so that to count is possible any of them. In favor by the latter I can give more pleasant interface and somewhat the more intelligible conclusion of results, although this all is subjective, most likely. But nevertheless, I will give an example of the use of the first program, as that it is more widely utilized for similar [rasschetov], and already with the second that you and themselves will be dismantled.
Thus, for the beginning it is necessary to introduce all necessary data about our dynamic loudspeaker:
We press the button “accept”, we go in the menu of program and will construct two graphs; one under the title Of optimum – this the fact that program will calculate on the basis of optimum output data and Custom – it is possible to change the calculated parameters and to look which this will leave.
Strictly speaking, us interests the calculated parameter Fc – the resonance frequency of our [sabvufera] depending on the volume of box, although in principle, us it will arrange and F3 – the same, on the level -3 dB.
In this case yellow line – this that the program calculated…
What what volume??? 133 liters and more? You will excuse me – I so many will not drink!
Will try to moderate appetites JBL- I and to reduce the volume of box, well let us say to 40 liters (42, which they are visible on the picture they came out somewhat later than the simply convenient sizes of the walls of box). As is evident, difference entirely even small, and already in the level -3 dB so generally practically they coincide.
It is solved! We make the closed box, with a volume of 40 liters or near that.
Further did come up the question of material – from what to make box? The knowing people said – [DSP] and only [DSP] – any tree. But is still better – [MDF] – it denser, heavier, and therefore will give less than overtones in sounding of [saba]. Well, [MDF] so [MDF], I thought and he left for the construction store, after the boards and the bars for their connection. Well and by wood screws with the glue, it is understood.
Everything stocked up, everything it brought home, it began to scrutinize – by the way transverse U-cut [entoy] [MDF] actually sufficiently interesting – you will look not [fotke].
Generally, how I understood, [MDF] – this by special means the pressed cardboard. But it must to you say – piece unusually heavy, actually.
However, everything was stocked up, time it was to begin the matter.
Panels were greased by glue and they attached to each other with wood screws. By the way, must to you immediately say – you will decide to make [sabvufer] – buy screwdriver – thing not too expensive, but passion what useful – makes possible for hands to remain whole and with unharmed and wood screws it turns with the whistle.
Well it is agreeable, further especially many commentaries will not be – simply a little the sequential photographs of the process of the putting together of box.
Since coils are two, joint it was decided to place dual – it is small whether that.
Well here, almost everything is prepared – it remained to smear box by sealing compound and to carry out the skin of walls by sound absorber. But of course I was not held and connected unfinished [sab] to the amplifier. It is better this not to make… Well yes it is agreeable – it is already necessary to bring the matter to the end.
As the gasket was selected [sintepon], as the most accessible means. When I was covered into the store “of cloth” and required the square meter of [sintepona], salesgirl they looked to me sufficiently suspiciously. It is agreeable, what you will not make for the skill.
[Sintepon] proved to be dual, so that displacing it again in half it came out the skin of 4-[mya] by the layers of [sintepona].
[Ekh], heat- there, must be winter will be.
Well, then after all these dances was included it again. Citizens, I want to you to say – give to the upholstering and to sound absorber there is very much attention and time. It that stands – I of that was convinced by his own ears. After the gasket of [sab] it began to sound perfected differently, than to the gasket. Appeared precisely bass – powerful, confident, elastic. It is shorter, it is the fact that necessary for the neighbors of hour on two nights. Although I and not sadist.
Well and one additional pict – practically finished sub during the tests.
That’s all. In the following part we will have a talk, about the calculation and the production low-frequency filter for sub and a little let us run on the amplifier for this.