Microphone mustache with circuit equalizer. An overview of the circuit diagrams of equalizers and tone controls. An example of the execution of inscriptions
Many radio amateurs, regardless of what kind of transceiver they have, are trying in one way or another to improve the quality of the transmitted signal. Who has the timbre coloring of the voice “wrong”, who has the wrong microphone. In self-made devices, correction is usually achieved by selecting the C and R values in the corresponding circuits of microphone amplifiers, or the frequency response is corrected using the simplest tone controls, owners of “branded” ones often buy expensive studio microphones and equalizers, the use of which in r / l technology is more unjustified than necessary .
Be that as it may, the use of an equalizer very often allows you to improve the signal, and you can do it almost for free if you carve out a couple of hours and make the proposed device yourself. The signal quality in this case will not be worse than when using the "proprietary" equalizer
In the journal funkamateur N 8 for 2004 p 801 Marcel Schneider published an article where he described a simple five-channel low-frequency equalizer on a chip TA7796P, designed for use at r / amateur r / stations, (Fig. 1). If you come across a chip for stereo devices, do not worry. On the second half, you can assemble an equalizer for the receiving path, which, although partially, will make it possible to compensate for the absence of a chipboard (or any other filter).
As a basis, the author took the scheme of Toshiba-manufacturer TA7796P(Fig. 2), which was designed for use in home appliances, adding an amplifier on V1 to use an equalizer in the microphone amplifier path and an emitter follower on V2 used in musical technology.
Variable resistors RP1-RP5 with a linear characteristic. Resistors of 50 kOhm can be used, in this case, instead of the jumper R *, a resistor with a nominal value of 3.3 kOhm is soldered, or others - R *, respectively, will have to be changed.
Fig.2
In my opinion, the capacitance of 10 µF isolation capacitors is unreasonably high, which only leads to clogging the signal with low-frequency noise, for example. from a fan or transformer, and therefore a capacitance of 0.047-0.1µF in the VT1 base is quite enough, as is a capacitance of 0.5µF in the VT1 collector; 1µF in VT2 emitter; in the VT1 OOS circuit, the capacitance in the emitter can also be reduced to 0.47-1µF.
The polarity of the coupling capacitor at the output should be clarified when using an equalizer with a specific transceiver, or even better, use a non-polar capacitor.
To match the level with the transceiver, instead of a constant resistor in the VT2 emitter circuit, it is better to put a trimmer or variable at the equalizer output.
Some data TA7796P:
Five-channel low-frequency mono equalizer E pit = 4-16V. I pit = 6 mA. Uin, Uout = 0.775V (0dB) Frequency response unevenness 20Hz-20kHz=1.5dB. Unoise = 3µV. K g \u003d 0.007% at U out \u003d 245mV.
Correction depth ± 11.5db. Analogues: DBL1046; KA2223; M5226P; LA3600; TA7796P
P.S. The device starts working immediately and without the changes I suggested.
Good luck with your repetition! 73!
Nikolai Polyukhov, Stuttgart
DF3NPex: UL7LCW; UL7LC; UN7LC; UN0L
5
- ti-band microphone - equalizer for the transceiver
Model<< ME 008>>
Ukraine, Kharkov
PURPOSE
The proposed equalizer is a device that allows you to set the required amplitude-frequency characteristic of the signal transmission channel (English equalize - equalize, equalizer - equalizer, compensator). It allows you to equip radio amateur stations with a complete device, including a high-quality electret microphone, combined with a 5-band equalizer. Microphone Application<< ME 008 >> allows you to get the necessary frequency response of the microphone path, which can dramatically increase the readability of the signal. This device is intended for radio amateurs who do not have an equalizer built into the transceiver, or as a separate unit.
DESIGN
and specifications
Structural execution.
The device is made in the form of a separate block of impact-resistant polystyrene, the entire inner surface of which is subjected to metallization in order to shield from external electromagnetic fields.
On the front and back panels there are all the necessary informational inscriptions made in Latin script. The use of modern technologies has made it possible to obtain high resistance to external influences on abrasion, etc.
The microphone holder, in order to shield from external electromagnetic fields, is made of a flexible metal hose about 25 cm long. The polished chrome coating gives it high resistance to external influences on abrasion, etc. and excellent aesthetic performance.
The weight of the device is about 250 gr.
Dimensions - 90 X 46 X 150 mm.
Bodies of regulation and management.
Regulators.
Frequency response controllers are made in the form of 5 axis controllers, which are displayed on the front panel of the device. The position of the knobs displays the frequency response of the device. A flat signal characteristic corresponds to the position of the knobs at 12 o'clock. Zavalu frequency response - 10 dB. and at the 8 o'clock position. Raising the frequency response in the position at "16 o'clock" In equalizers of this type, the regulator installed on the rear wall of the device, you can adjust not only the magnitude of the rise in the frequency response blockage, but also the level of the output signal to a significant extent. Other parameters are determined by the circuitry and cannot be changed.
Governing bodies.
The device also contains a push button switch.<< PTT >> push-type (non-latching) designed to transfer the transceiver to the "TRANSMIT" mode by pressing it with the index finger. Switch<< PTT >> installed on the top panel (red button). To the right of the button<< PTT >> a push-type button (non-latching) is installed, designed to tune the operating frequency of the transceiver up in frequency a on the left side of the button<< PTT >> a push-type button (non-latching) is installed, designed to tune the operating frequency of the transceiver down in frequency.
Detachable connectors.
On the rear panel of the device there is an 8-pin connector designed for:
1) generated signal output<< OUT >>
2) switching circuits<< RTX - PTT >>
3) control (tuning) of the transceiver by frequency
There is also a 3.5 mm jack on the rear panel for connecting a standard microphone head or a headset with a microphone.
On the rear panel there is also a special connector for supplying voltage +13.8 V.
The device is connected to the transceiver using a special cable 0.75 meters long, included in the delivery, on one side
equipped with an appropriate connector for connecting to the device, and on the other hand with a special 8-pin connector (supplied with a separate order).
Specifications.
The frequency response adjustment limits are not less than 10 dB. + 12 dB.
Harmonic coefficient no more than 0007%
Noise at a frequency band of 50 Hz. - 5KHz. no more than 3 Mkv.
Protected from external email. magnetic fields - complete shielding by metallization of the inner surface of the product body and microphone holder.
Protection against the penetration of external interference through the connecting cable - the use of a P. - shaped filter for the power circuit, a P. shaped filter for the microphone input circuit
Supply voltage - from an external power source of the transceiver 13.8 Volts
Current consumption - 15 mA max.
Note.
Characteristics measured with "flat" frequency response bandpass filter controls in the middle position at "12 o'clock"
Contents of delivery.
1) 5-band microphone - low-frequency equalizer for the transceiver
2) Connecting cable + special 8-pin connector - 1 pc.
3) A piece of wire (red color) equipped with a special connector for supplying voltage 13.8 V. from the power supply of the transceiver
4) Wind-noise foam screen
5) Packing box
<< KENWOOD >> << ICOM >> << YAESU >> and T.P..
The special 8-pin connector cable part (female) connected to the product is provided with a red label.
R connection cable soldering
ME 008
1 pin - (+ MIC)
2 pin - (+ PTT)
3 contact - (F. DOWN)
4 pin - (F. UP)
5 pin - (N C is not used)
6 pin - (N C is not used)
7 pin - (-MIC)
8 pin - (supply - voltage 13.8 Volts from the microphone connector of the transceiver to the product)
Supply voltage applied
from the power supply unit of the transceiver with a red (only +) wire equipped with a special connector included in the product delivery set
Or from another connector located on the rear panel of the transceiver on which there is a voltage of the on-board network of the transceiver 13.8 volts.
Attention!!!
Connect the connecting cable to the microphone with the power supply switched off.
The wiring of the microphone cable on the side of the transceiver must be carried out by an appropriately qualified specialist.
The manufacturer reserves the right to make changes to the device scheme and external design.
All changes are aimed at improving the electrical parameters and ergonomics of the product.
Please send your feedback and wishes by e-mail:
radiobomb@mail.
Ukraine, Kharkov
2008
Eight-band equalizer with two microphone amplifiers, with sound processor "echo" and "reverb", with VLF for self-audibility
An eight-band equalizer with two microphone amplifiers with separate gain control and a choice of microphone type (dynamic or electret), input impedance 200/600 Ohm or high-impedance input, with echo and reverb effects, with VLF for connecting headphones for self-control during tuning and two separate outputs for connecting, for example, two transceivers, powered by a DC source with a voltage of 7.5 to 25 V. The device consumes a current of about 30 ... 40 mA.
- top row - equalizer variable resistors 50Hz, 100Hz, 200Hz, 400Hz, 800Hz, 1600Hz, 2400Hz and 3200Hz ;
- bottom row - variable resistors ULF listening, effect level "echo" , effect level "reverberation" , 6.3 mm jack and gain control microphone number 1 , 3.5 mm jack and gain control microphone number 2 .
Photos of printed circuit boards and kits for assembling a microphone amplifier with an equalizer:
Panel mounting example for enclosure mounting:
An example of the execution of inscriptions:
Here's a short video of the equalizer in action. It is better to listen to headphones or speakers that reproduce low frequencies normally.(the amplification on the first input was "wound up" more than on the second, therefore, at the very end of the video, when the MD-380A microphone is demonstrated, the signal is limited):
Structurally, the microphone amplifier is made on two printed circuit boards. On the board installed on top, an eight-band equalizer is assembled on common dual operational amplifiers ():
On the board installed at the bottom of the operational amplifiers, two absolutely identical microphone amplifiers with separate gain control are assembled. The input of one of them has a 6.3 mm plug socket, and the input of the second has a 3.5 mm plug socket. The board has a J1 jumper to supply power to the electret microphone. When using a dynamic microphone, this jumper does not need to be set. Jumpers J2 and J3 can be used to set the input impedance of 680 and 200 ohm amplifiers. If the jumpers are not set, then the inputs are high-resistance. It is possible to use both microphone inputs at the same time, ie. mixing (simultaneously broadcast speech and music :)). The signal from the microphone amplifiers is processed by an equalizer and fed through two separate operational amplifiers to the output terminals for connecting transceivers or something else. In addition, the board has a PT2399 sound processor, which allows you to decorate the signal with the effects of "echo" and "reverb". To adjust the depth of the effects, two variable resistors "Echo" and "Delay" are installed on the board. In order to preliminarily evaluate the processed signal by ear, an ULF was assembled on the board on the LM386 chip. You can connect headphones or a speaker with a power of up to 0.5 W with a resistance of 8 ohms to the amplifier. Schematic diagram of the board of amplifiers, ULF and sound processor ():
Depending on local conditions and the sensitivity of the microphone input of the transceiver, it may be necessary to install a trimmer resistor and a 2200...4700 pF blocking capacitor. The trimmer resistor must be set to such an output signal level that the microphone gain control on the transceiver is set to 20-30% of full gain
The cost of a pair of printed circuit boards with a mask and markings (board size 150x40 mm): 270 UAH
The cost of a set of parts with printed circuit boards for assembling a MU with an equalizer (racks and handles for variable resistors included): 600 UAH
The cost of assembled and tested MU boards with an equalizer ( knobs for variable resistors included) : 800 UAH
Brief instructions for the kit and the composition of the kit can be seen
Orders can be placed through the form or by phone specified in the section
Peaceful sky to all, good luck, kindness, 73!
4-BAND LOW EQ
The most common and most widely used processing of audio signals is the processing associated with changing their timbre. Today, you can often find radio amateurs who have an equalizer built into the transceiver or located outside it - a device capable of equalizing the amplitude-frequency characteristic of the signal transmission channel (eng. equalize - equalizer to equalize equalizer, compensator).
We are not talking about equalizing the frequency response in the literal sense of the word and the identity of the signal amplitude in the entire frequency spectrum of the microphone amplifier, since this is not necessary. Creating the necessary frequency response of the microphone path, which can dramatically increase the readability of the signal - that's the task.
An equalizer is a frequency response control that allows you to both correct poor sound quality and create a completely new frequency response in accordance with the need.
The simplest example of an equalizer is the usual passive tone controls for high, low, and sometimes mid frequencies. Tone controls are an extremely primitive type of equalizer, since they consist of only two or three controllable filters. Due to the simplicity of the design, the filters that make up the tone controls are usually connected in series.
The modern element base allows the use of more advanced devices assembled on active elements. We are talking about active band-pass filters on the op-amp. It should be noted that the more filters, the more you can change the frequency response. Usually they are used 8-10.
All types of equalizers can be manufactured according to two very different construction principles - in series or in parallel. In a serial circuit, the signal
passes through all the elements and nodes of the circuit, regardless of whether this part of the signal spectrum changes in this stage or not. In a parallel circuit, the input signal is divided by a series of filters connected in parallel into a number of frequency bands, the output signals of which are then added to or subtracted from the input signal.
Parallel connection of filters in the tone control, in contrast to series, allows you to reduce the phase distortion introduced by the equalizer into the signal. This is especially important with 10 or 32 graphic EQ bands, where only parallel connection of filters is acceptable.
There are two fundamentally different types of equalizer - graphic and parametric.
A graphic equalizer is, in essence, one of the varieties of tone blocks designed to control the tone at several fixed frequencies. Its controls are made in the form of slide controls, due to which the position of their knobs, as it were, displays the frequency response of the device in a graphical form, from where the name itself came from. In equalizers of this type, only the magnitude of the rise and fall of the frequency response can be adjusted, the rest of the parameters are determined by the circuitry, and it is impossible to change them.
The parametric equalizer has the greatest flexibility of its adjustments. It allows you to control not only the gain of the filter, but also its middle frequency, as well as the quality factor (the width of the adjustable band). The parametric equalizer, therefore, has three controls for each control band - according to the number of parameters to be set.Thus, if the equalizer has three control knobs for each control band, then this is a parametric equalizer.
Like graphic equalizers, parametric equalizers can also be implemented in parallel or in series. The ranges of parameter changes in the parametric equalizer reach significant values.
A semi-parametric equalizer is sometimes used in mixing consoles. It allows you to control the filter gain and its center frequency. It differs from the parametric one in that it does not have the ability to change the quality factor of the equalizer, the bandwidth of the frequencies it captures.
The paragraphic equalizer is a hybrid of the parametric and graphic equalizers. Actually, this is a multi-band parametric, but having a design of the frequency response rise / fall regulators like a graphic one, with potentiometers in the form of sliders. Due to its huge capabilities, the paragraphic equalizer allows you to get almost any type of frequency response. Due to its complexity and high cost, this type of equalizer is not widely used, but is produced by some manufacturers.
Microphone - MD380A. VR 1 "Microphone" - 80% (up to 250 mV at the input DA 2), VR 2 "Gain" - 90%, VR 3 "High" -100%, VR 4 "Mid 2" - 100%, VR 5 "Mid 1" - 50%, VR 6 "Low" -100% , VR 7 "Output" (in the "Output 620 Ohm" position) - 80% (in percent, the position of the potentiometer slider when rotated clockwise is given).
To power the equalizer, a bipolar stabilized unit is required.supply voltage 15 V and current up to 100 mA.
I would like to add that the equalizer is not a panacea, but a signal correction tool. It can remove the excess, but with its help it is extremely difficult to add something that was not in the path, so everything is important: the voice of the operator, and the frequency spectrum of the microphone used, and the presence of the equalizer itself.
An equally important issue is the correct setting of the frequency of the reference oscillator in SSB -shaper and the bandwidth of the filter used in it. The wider the bandwidth of the filter for transmission, the easier it is to receive a studio signal.
I want to thank Alexander EW 1 RA, who once presented me with the Sonor M-08-3 mixing console, which contributed to a more detailed study of this topic.
The results are as follows - the mixing console, after its global study and reconstruction of the circuit diagram, was disassembled into sub-units, the eight 4-band speech equalizers that were in it were donated to other radio amateurs. A modernized 4-band equalizer with sufficiently high characteristics has been created.
Circle of Audio Lovers expands Thank you F 4 ECJ , Erie , G 4 VPC , Erpey, G 4 EKL , Tony , EW 1 DM , Serge , RW 3 PS , Serge and especially EW 1 RU , Yuri for constructive discussions on topics related to audio processing
A printed circuit board with a size of 170x50 mm (Fig. 4, view from the side of the installation of parts and Fig. 5, from the side of the tracks) was developed by E.W.2CE, Alexander Railchenko
I. Podgorny, EW1MM, MINSK.
The next tone control already has six control bands, and a separate operational amplifier is used for each band. The original version of this EQ was five-band, but by expanding the number of bands and using quad op-amps, you can get by with just 4 DIP14 packages for the stereo version, instead of the 16 DIP8 that would be required using single op-amps. A schematic diagram of this equalizer is shown in Figure 22. This option can already be safely called a graphic equalizer, since when using slider variable resistors installed in one line, the overall frequency response of the equalizer will already be visually visible, i.e. graphic display of the adjustments made.
Figure 22 Schematic diagram of a six-band graphic equalizer.
INCREASE
Figure 23- shows curves showing the change in frequency response depending on the change in the resistance of the control resistors.
Figure 23 20 Hz adjustment.
Figure 24 100 Hz adjustment.
Figure 25 500 Hz adjustment.
Figure 26 2000 Hz adjustment.
Figure 27 1000 Hz adjustment.
Figure 28 20000 Hz adjustment.
As can be seen from the figures, the frequency response curves have a fairly symmetrical shape both in the frequency range and in the limit of increase or decrease of a particular band, which makes it possible to use this equalizer in medium and high class equipment.
The use of bandpass filters can be organized not only in the same way as in the previous version, but also somewhat differently. An example is the equalizer shown in Figure 29. Each bandpass filter is essentially an electronic analogue of a capacitor and an inductor connected in series.
Figure 29 Schematic diagram of a six-band graphic equalizer. INCREASE
Figures 30-35 show the frequency response at the extreme positions of the variable resistors. By the way, the range of adjustments can be slightly expanded by changing the values of the resistors along the "edges" of the switches, but not less than 1.5 kOhm. The quality factor of the filters, of course, leaves much to be desired, nevertheless, the circuitry of this equalizer is quite popular.
Figure 30 Adjusting 30 Hz
Figure 31 Adjusting 90 Hz
Figure 32 Adjusting 200 Hz
Figure 33 Adjustment 700 Hz
Figure 34 Adjustment 2000 Hz
Figure 35 Treble Adjustment
The frequency range is slightly shifted to the low-frequency side, so it is better to recalculate if you plan to use this design not in a domestic environment.
Another version of the eight-band equalizer is shown in Figure 36. In terms of circuitry, this tone control consists of six band-pass filters, the signals after which are simply summed and amplified by a buffer amplifier. This variant has its own gain coefficient, which is why the input amplifier X1 serves as a divider of the input signal, i.e. initially weakens it.
Figure 36. Schematic diagram of the graphic equalizer on the op-amp
INCREASE
When constructing the frequency response of the equalizer, a rather interesting thing turned out - this regulator only enhances the selected band, and the attenuation is so small that it can be neglected (Figure 37).
Figure 37 Change in frequency response depending on the position of the variable resistor X2 slider.
Of course, that such behavior aroused suspicions about the correctness of transferring the circuit diagram to the simulator. A thorough check of errors did not reveal, so it was decided to check what actually happens in the filters themselves, depending on the change in the positions of the variable resistors. To begin with, ALL the sliders of variable resistors were moved to a position that increased the rise of each band, and the frequency response was taken at the outputs of the X10-X17 op-amp. What happened was pleasing to the eye - the change in shape is quite symmetrical and the quality factor is not bad (Figure 38).
Figure 38 Frequency response of each filter with increasing filter gain
Next, the variable resistor sliders were moved to decrease each filter and again the frequency response was taken at the output of each filter. The picture turned out to be also very beautiful - neither the frequency nor the quality factor changed (Figure 39).
Figure 39 Frequency response of each filter with a decrease in filter gain
Well, in this case, what happens if both the range of filter adjustments and the quality factor are good, and in the final, the rise is only 9 dB, and the blockage is even less?
The answer to this question is quite simple. The equalizer circuitry is to blame for everything, namely the summation of the signals after the bandpass filters. The fact is that with an increase in the amplitude of one section of the frequency range, passing the adder, the signal is significantly weakened and, as a result, the increase in amplitude occurs not by the expected 20 dB, but by only 9 dB. When the amplitude of one section of the frequency range is attenuated, self-attenuation occurs, but only in the filter, and at the output of the adder, this attenuation is compensated by equal frequency response in the attenuated section by other filters. Thus, the more bands there are in the equalizer according to this circuitry, the smaller the adjustment range will be.
Based on the foregoing, it can be concluded that the author of this publication ALL I made calculations by collecting only one or two filters, and all calculations and measurements were carried out not in a full-fledged device, but only using its fragments, since it is not possible to obtain a five-band equalizer with an adjustment range of ±12 dB, especially -12 dB in a finished device.
However, to speak FUUUU!!! this circuitry is not worth it, since on its basis it is possible to build a rather good bass-treble tone control, and the rise-blockage will occur exactly where the nonlinearity of the frequency response of the acoustic system is maximum and where most often it is required to slightly raise the amplitude. To do this, it is necessary to leave only the upper and lower bandpass filters, and reduce the values of the resistors R37, R44 and R46 to 10 kOhm. The result is a quite decent adjustment of the frequency response at the edges of the audio range (Figure 40).
Figure 40 The shape of the change in the frequency response at the extreme positions of the sliders of the variable resistors of the "shortened" equalizer.
The same filters can be used in devices that only need to raise the frequency response at a certain frequency or select a certain frequency, for example, a spectrum analyzer or a light-dynamic installation (color music).
As the next device for adjusting the frequency response, consider a circuit diagram of an equalizer with adjustable bandpass filters and not quite the usual circuitry. The schematic diagram of this device is shown in Figure 41.
Figure 41 Schematic diagram of a professional five-band equalizer.
INCREASE
This equalizer differs from previous versions primarily in the use of two operational amplifiers for one bandpass filter. This increase in detail primarily pays off with additional features, namely the ability to adjust the pseudo-resonance frequency of the filter and adjust the quality factor. This, in turn, completely eliminates the selection of frequency-setting elements (in the equalizer it is recommended to use parts with a spread of no more than 1%, otherwise selection is necessary to obtain the necessary frequencies and similarity of adjustments in stereo versions). In addition, if the 22 kΩ trimmers in the bandpass filters are replaced by 10 kΩ and connected in series with 22 kΩ variables, you can get a parametric equalizer that has much more capabilities compared to graphic equalizers. The main advantage of parametric equalizers is the ability to adjust not only the level of a particular frequency, but also choose the frequency itself, as well as change the steepness of the cuts or rises of the variable frequency. For this reason, a three-band parametric equalizer is preferable to a five-band graphic one, but there is nothing to say about a five-band parametric equalizer - this is a device for recording studios and requires a trained operator.
But back to the circuit and for now consider the operation of one bandpass filter. Figure 42 shows the change in the frequency response of the entire device at the maximum and minimum Q factor of the mid-frequency bandpass filter (the Q factor changes in the other filters in the same way).
Figure 42 Change in quality factor, regulated by resistors X14-X18.
Figure 43 Frequency change, regulated by X8-X12 resistors.
Figure 43 shows the frequency changes of a band pass filter. The figures clearly show the wave-like frequency response at the edges of the adjustable frequency. The appearance of this effect is associated with an unreasonable increase in the adjustment range - up to a level of ±16 dB, which in itself is already too large a range. By reducing the adjustment range (increasing the value of resistors R1-R5), it is possible to achieve a fairly significant decrease in this waviness, and with an adjustment range of ±12 dB, the maximum peaks of the "waves" will be at the level of 1-1.5 dB, which is quite difficult to distinguish by ear.
Figure 44 shows a schematic diagram of a ten-band graphic equalizer using the same circuitry. In fact, this scheme differs from the previous one only in an increased number of bands, everything else is completely the same.
Figure 44 Schematic diagram of a ten-band graphic equalizer.
INCREASE
The approximate frequency band in this embodiment is adjusted by the appropriate resistors and has the form shown in Figure 45, although it can be changed depending on the needs of a particular sound engineer.
Figure 45 An example frequency grid of a ten-band equalizer.
INCREASE
In addition to building equalizers, bandpass filters can be used one at a time to correct a particular frequency or range. For example, if you use only the lowest-pass bandpass filter, you can get a rather interesting filter for a subwoofer.
Well, actually, all the main options for tone controls with all the pluses and minuses.
Frequencies to remember
The network (power) is noisy at a frequency of 50 Hz (and multiplies). To eliminate this, it is necessary to remove the frequencies of 50 and 100 Hz using a parametric equalizer, the bandwidth of which is quite narrow. Then it will not noticeably affect the overall sound, but will eliminate network noise. A graphic equalizer (one third of an octave) is also applicable in this situation, but it is better not to use other types of equalizers for this, as they have too wide (zone of influence) and adjustment can seriously change the sound of a 6ac guitar.
The low frequencies of the bass guitar and bass drum lie in the region of 40 Hz or less. To give these sounds power (attack), adjust the frequency to 80 Hz. Many modern mics designed for the bao drum have a slight peak at this frequency, resulting in a nice, thick sound.
The lower frequency of the electric guitar is 80 Hz. To eliminate barreling, you need to cut the frequency of 200 Hz; to eliminate an unpleasant sharp overtone - weaken around 1 kHz. In any case, the sweep equalizer must be tuned by ear. Use a hi shelving control to achieve a high-pitched sound. You can also experiment with the bell equalizer (6 kHz - 10 kHz). To "poison", to "sting" the sound of a rock guitar, scan the region from 1.5 kHz to 4 kHz, find the desired frequency and reduce it until the attack is just right.
The main problem with acoustic guitars is that they tend to sound bassy (due to inappropriate mics, mic position, room acoustics - or simply because the instrument is bad). A sweep equaliser can be used to remedy this shortcoming: the "harmful" frequency region is usually between 200 Hz and 500 Hz; it needs to be cut out. Boosting in the low-mid region is likely to make the sound harsh, so it's always best to use a high fade filter if you want to give your guitar a special brilliance.
Vocals also take up a large portion of the frequency range, with the 2-4kHz region adjustable for improved articulation. Try to avoid high amplification whenever possible, as the natural sound of the voice may be lost. Use the top fade-in and fade-out filter to brighten up your voice if needed; bell equalizer is hardly applicable here.
Description of the methodology for constructing equalizer models in the MICROCAP simulator:
