FOZGOMETER AZIMUTH RANGE FINDER
To obtain high performance from a modern phonograph system, the tonearm and pickup cartridge must be properly adjusted to within a few thousands of an inch. There are several alignment gauges available to adjust overhang and offset. To adjust cartridge azimuth (Axial Tilt), it has been necessary to use lab quality equipment and a test record. Azimuth may be adjusted using an oscilloscope, AC voltmeter, or computer program. These methods can be expensive and time consuming.
The FOZGOMETER represents a breakthrough for adjusting phono system azimuth. The FOZGOMETER incorporates a "Log Ratio Detector" developed for surround processor steering logic circuits to measure channel separation over a wide range of signal levels down to -70 dB. The readings are virtually independent of overall signal levels, and can be made with a wide range of input signals without effecting accuracy. It is a small portable battery powered unit that is used in conjunction with a test record. It measures channel separation, channel balance, and signal direction quickly and accurately. Readings are taken without touching the meter, leaving your hands free to work with the tonearm. The meter reads channel separation in both directions, and channel balance. The LED's indicate Left, Center, and Right signal (test tone) positions.
The Fosgate Fozgometer works well with the Analogue Productions Ultimate Analogue Test LP or your Test LP with an Azimuth Test Cut.
The ANALOGUE PRODUCTIONS ULTIMATE ANALOG TEST 180g LP
Analogue Productions set out to produce the ultimate test record:
We've consulted many experts in the field, including mastering engineers, audio experts, turntable experts and audiophile listeners, to create a test record that's never been made before. When Barry Wolifson from Sterling Sound in New York City called us with the same idea we had been thinking about - that being to create the ultimate test record - he and our audio expert Clark Williams began to brainstorm and research ideas until they were both completely satisfied with what should go on the record.
Most of the test records in the past have been made to test a variety of equipment. This test record excludes silly cannon shots, typewriters, voices on one channel and other useless fluff. This one specifically addresses your turntable and cartridge. It's designed to provide the basic test signals necessary to calibrate a turntable or cutting lathe as simply as possible. Most of the signals have specific implications, but it is certainly possible to use them in any number of novel ways.
This record was mastered and cut on a Neumann VMS 80 lathe at Sterling Sound and pressed at Record Technology, Inc. on high-quality, 180-gram virgin vinyl.
. 180g Virgin Vinyl
General Reference Level
This 1 kHz reference tone will allow you to establish a "base level" for all measurements.
Track 1. 1Khz reference tone 7cm/s lateral in phase (mono)
Basic reference for all measurements, adjust meter for maximum convenience (in the studio 0VU).
Adjust preamp channel balance for equal output.
Also used to check the offset angle of the photo cartridge; L&R signals should be exactly in phase as displayed on an oscilloscope.
Track 2. 1kHz reference level, Left channel only
Measure Right channel output.
Track 3. 1kHz reference level, Right channel only
Measure Left channel output.
The object is to sit the stylus exactly perpendicular in the groove.
Twist cartridge about its radial axis until the measurements from Track 2 and Track 3 are equal or very close to equal for both channels.
High Frequency Adjustment
Tracks 4-6 are used to calibrate the RIAA high frequency equalizer of a phono preamp. This will be used to calibrate a mastering lathe's phono preamplifier or any phono preamplifier that has these adjustments.
Track 4. 1 kHz tone at -20db below reference level, Lateral
Reference for High Frequency test.
Track 5. 10 kHz reference tone at -20db, Lateral
Adjust the high frequency until the output level equals that of Track 4.
Track 6. 1 kHz to 20 kHz sweep at -20db, Lateral
The AC millivolt meter reading should stay constant across all frequencies. There are a number of factors which can affect frequency response, including cable capacitance, cartridge loading, tracking force and worn parts. Because of this, it can be difficult to achieve perfectly flat frequency response. Sometimes by making small compromises in the 10 kHz adjustment, a better overall frequency response can be achieved.
Low Frequency Adjustment
Tracks 7 & 8 are used to calibrate the RIAA low frequency equalizer of a phono preamp.
Track 7. 1 kHz to 20 Hz sweep at 0VU (Lateral)
Play Track 7 and measure the output with your AC millivolt meter.
Ideally, the output will be flat across all frequencies. When viewed on an oscilloscope, the amplitude would remain constant during the frequency downsweep.
Track 8. 100 Hz reference tone at 0VU (Lateral)
Adjust LF Eq to reference (which is your reading from Track 1).
Track 9. VTA adjust
This is an IEC intermodulation distortion (IMD) test signal; 60Hz & 4kHz 4:1 ratio.
Using an IMD tester, adjust VTA by raising or lowering the tonearm for minimum distortion.
Track 10. Standard Wow & Flutter test signal; 3150Hz
The Wow & Flutter meter will give dynamic speed variations as a percentage deviation from nominal.
Also, the frequency counter should read exactly 3150 Hz for nominal speed. You can use the Hz function on your multi-meter (if so equipped) to verify speed here as well. You can also use to find the measurements at 45RPM. The correct reading at 45RPM would be 4253 Hz (45/33.33) x 3150.
Track 1. Anti-skating test; 315Hz amplitude sweep to +12db (Lateral)
Signal should remain clean in both channels up to the highest level, both audibly and as viewed on an oscilloscope. In case of distortion, increase anti-skating force or decrease anti-skate until breakup occurs equally in both channels. The left channel information is inscribed on the inner groove wall, the right channel information, on the outer groove wall. Because of the offset angle of a pivoted tonearm, a constantly varying vector force biases the arm towards the center of the record causing the stylus to lose contact with the outer (i.e. right channel) groove wall. Both linear and modulated groove velocity, tracking force, stylus profile, and vinyl composition are contributing factors. The anti skating force attempts to ameliorate this by applying an opposing similar force.
It is also accepted that the overall force vector increases as the tonearm approaches closer to the spindle or end of the record.
Track 2. Pink noise lateral
Track 3. Pink noise vertical
Used for cartridge "demagnetizing"
You can also use this track to loosen up the cantilever's suspension to help break in a new cartridge. Play these tracks five to ten times after every 300 hours of normal LP playback.
Track 4. 1kHz at reference level, vertical
This out-of-phase signal should cancel to nothing when summed to mono.
Any signals still present are distortion artifacts, lack of channel balance, or timing (phase) anomalies. This test can be a second confirmation of anti-skate adjustment.
Track 5. 1kHz to 10Hz sweep at -20db below
reference level, vertical
Resonance anomalies in the tonearm / cartridge interface will show up as amplitude peaks and dips as the frequency sweeps down.
Once again, by listening in 'Mono' it is easier to hear the distortion artifacts.
Track 6. Silent groove for bearing rumble and table isolation
During playback of this track, nothing should be transmitted from the turntable to the speakers. Replay the track and gently tap on the rack or base that the turntable is resting on. There should be little or no thump transferred to the speakers. This track will help you experiment with turntable isolation methods and products to be able to get the most out of your playback system. You may want to use a closed or sealed headphone for best listening results, or a stethoscope on the plinth.