The Fender Twin 73 IR Pack is a set of 10 impulses (IR) from Shift Line that can be used with our CabZone cabsim or any other hardware or software cab simulator. The impulses were filmed and edited at the Shift Line studio in St. Petersburg. This set is the fourth in a series of cabinet impulses featured on our site, and contains impulses from a 1973 Fender Twin combo amp.

The pulses are prepared in mono 24bit 48kHz WAVE PCM1 format, without compression. The pulse length is 1000 samples (about 20 ms), which is sufficient to transmit a reliable frequency response of the cabinet without the influence of the room and additional spurious reflections. All dialing impulses are reduced in volume to the same value to eliminate the “louder is better” effect.

✔️ From the Authors:
The 1973 Fender Twin (Silverface) combo amp with JBL D120F speakers is one of the best amps for clean sound according to the entire Shift Line team. However, it is good not only for clean, but also for all kinds of crunch, breakup and midgain, and is also great for almost all fuzzes and external overloads. Yes, this is not an amplifier for classic metal styles, but even in them they find use.

What is the ’73 Twin and why is it so remarkable?
First of all, this is an open cabinet with two twelve-inch JBL D120F speakers, a characteristic feature of which is a peak around 4000 Hz. This resonance is a clever “presence” filter that successfully emphasizes the “glass” of the Stratocaster and complements the thick sound of the Les Paul. In pulses it has different magnitudes, but is always present. This will allow you to choose the nature of the effect to suit your taste. Additionally, when paired with this cabinet, Fender’s spring reverbs produce the most authentic surf sound possible.

We are confident that all impulses, even those taken from the same amplifier model, are unique. The pulses were recorded with two microphones: Sennheiser e906 and Lomo 19A19. A Fender Twin power amplifier was used to capture the pulses. The set contains 10 impulses with different microphone positions, their combinations and the balance between them.

Instructions for use:
Unpack the archive into the root directory of an empty microSD card when using CabZone LE (the AFX folder and text description files should appear on the disk) or copy the necessary impulses to the appropriate SD folders for Twin MkIIIS, having previously deleted the old files.

All impulses in the set are in mono 24bit 48kHZ WAVE PCM1 format without compression and are adapted to work with our devices: the A+ CabZone LE impulse cabinet simulator and the Shift Line Twin MkIIIS tube preamplifier. Naturally, they can be used in any compatible device or application that supports this format.

Details about the files in the set:
The pulses presented in the set have the minimum required frequency correction and represent a cast of a specific “amplifier/cabinet/microphone/preamp” combination. The positions of the Sennheiser e906 and Lomo 19A19 microphones are not always completely identical; In some of the impulses, the right, and in others, the left speaker of the combo amplifier is used. A common distinguishing feature of the Lomo 19A19 microphone is its always wider frequency response bandwidth (the sound is more “open”), while the Sennheiser e906 has a focused character. In most cases, when used in a dense mix, the Sennheiser is more suitable. In turn, Lomo 19A19 is good for spatial and sparse games.

The names indicate the position and type of microphone for quick orientation. And now – a more detailed description of each impulse.
The first pair of impulses is dome edge: captured by a microphone aimed at the edge of the protective cap from a distance of 10 cm from the speaker. Perhaps this microphone position can be called the closest to the real perception of the combo in direct interaction. Despite the almost identical position of the microphones, the overall frequency response has quite large differences.

01 Twin73 dome edge L19 – Lomo 19A19 has a boost around 80 Hz and a cutout at 380 Hz, the high-frequency response drops off sharply above 10 kHz. Perfect for clean sounds and gives a characteristic “volume” to the sound, including due to the dip in the lower middle.
02 Twin73 dome edge e609 – unlike Lomo, the Sennheiser e906 in this position has a rise in the lower mids around 600 Hz and a slight dip around 2 kHz. The roll-off of the high frequencies begins around 7 kHz. This gives the sound a “roundness and softness” that will come in handy in a viscous, light overload.

The second pair of pulses is center: captured by a microphone aimed at the center of the protective cap from a distance of 10 cm from the speaker. Both microphones in this position clearly emphasize the resonance around 4000 Hz. This gives the sharpest sound for maximum cutting through the mix. The overall frequency response of the microphones is almost identical, but the nuances allow you to choose the one that fits better into the mix, taking into account the rest of the path, starting with the guitar.

03 Twin73 center L19 – Lomo 19A19 sounds more open (both towards bass and at high frequencies), but at the same time more smooth than Sennheiser.
04 Twin73 center e609 – Sennheiser e906 gives a slightly brighter sound due to less impact in the lower range.

The third pair of pulses is cone20: captured by a microphone aimed at the center of the speaker cone from a distance of 20 cm from the protective grid. This position gives a pretty good overall picture of the sound of the combo amplifier, while both microphones in this position have a less pronounced resonance around 4000 Hz. Perhaps this group gives the smoothest frequency response of all: in the range from 250 to 2800 Hz the frequencies are very similar and do not have sharp changes.

05 Twin73 cone20 L19 – Lomo 19A19 is classically more open in the lower frequencies and even has a slight rise centered around 60 Hz, while the peak at 4 kHz is soft and 2 dB quieter than the Sennheiser.
06 Twin73 cone20 e609 – despite less openness in the upper frequencies than Lomo, the Sennheiser e906 sounds a little brighter in this position. This is partly due to a sharper low-frequency roll-off at around 90Hz, and partly due to a more pronounced peak at 4kHz.

The fourth pair of impulses is cone: captured by a microphone aimed at the center of the speaker cone from a distance of 5 cm from the protective mesh. A closer setting gives a more focused image, but emphasizes the resonance at 4 kHz more, with an overall frequency balance shifted towards the bass range. This group of impulses is for those who need to tame an overly zealous high-frequency overload.

07 Twin73 cone L19 – Lomo 19A19 is traditionally slightly wider in range with a light filter around 1 kHz
08 Twin73 cone e609 – Sennheiser e906 is narrower with a small filter around 500 Hz.

The fifth pair of impulses is the sum of two microphones: they were taken from different positions, but they are united by one feature – the impulse of the cabinet, filmed from the back side of the speakers. The cabinet of a combo amplifier is open, and quite often it is removed from two points, mixing the additional signal to varying degrees with the main one to give more volume or frequency correction.

09 Twin73 cab plusback L19 – Lomo 19A19 was installed at a distance of 50 cm from the center of the cabinet, and also 50 cm behind. The signals were phased and mixed in equal proportions. The result was unexpected, but interesting. A number of soft notches appeared in the frequency response, and the overall impulse acquired a slight “boxiness” of sound, which could well be used as an artistic device.
10 Twin73 dome edge plusback e609 – sum of impulses of the Sennheiser e906 microphone. One was removed from the edge of the protective cap of the speaker (15 cm from the protective grid), the second was removed from the back side of the cabinet at an angle of 45 degrees. The pulses are phased and mixed in equal proportions. Unlike the version with Lomo, this impulse has a completely natural sound, while the upper mids sound emphatically bright. Great for blues.