Speakers full-range with a high resistance.

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26 mH with a minimum resistance of 800 ohms impedance will doubling approximately 5 kHz.
That very early for full-range speakers:
F = (159,2 x 800 ohms)/26 mH = 4,9 kHz
Inductance very uncomfortable. It varies with frequency, though non-linearly.
Therefore, use a different, very convenient parameter. Which is easy to measure and standardize. Its easy to see in the impedance curve. Which usually results in a single graph of the amplitude frequency response.
This is the frequency doubling of the minimum impedance: F2z. This point roughly corresponds to the double maximum possible reduction of the current at a constant level of the input voltage through the speaker.
Minimum impedance in these speakers typically at frequencies of 150-300 Hz.
Has set for itself for optimum resonance in 8" full-range speakers.
This 45-60 Hz.
Then, at low frequencies there is no problem. And sensitivity is non reduced.
Parameter F2z full-range speakers with a wide range of often 15-27 kHz.
Very well when more than 40 kHz.
This area of ​​work is very good tweeters.
 
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Diagram complex impedance with frequency TFR8-2000, №14
Clearly seen that the inductance of the coil (at 1 kHz) does not matter much.
150 Hz / 20 kHz - almost a straight slanted line!
Z very complicated dependence on frequency.
Expressed in dB: 0 dB = 2 kOhm.
Full-range speaker, 2 kOhm nominal.
 

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Couple TFR8-1000, №22, №23.
This pair experienced. More than the usual reduced inductance. As a result, the shifted F2z to higher 5-10 kHz range. The mechanical quality factor is reduced.
Deviation of the impedance in the band 80-20000 Hz at №22 was 1.44; at №23 - 1,51 times.

Thiele-Small parameters: DC resistance, Re; resonance frequency, Fs, Hz; Q-- mechanical, Qa; electric, Qe; complete, Qt; equivalent volume Vas. Frequency doubling of the minimum impedance F2z, kHz.
........Re, Ом;....Fs, Гц;.....Qa;.......Qe;.....Qt....Vas, л,....F2z, кГц.
№22...770.........51,8......5,20.....1,60...1,20....-...........53
№23...760.........50,5......4,96.....1,53...1,17....-...........48
 

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There are measurement results speakers with a nominal 1000 and 2000 ohms, in the anechoic chamber, strictly according to the classical method.
Deviation in the range above 100 Hz is not more than 0.5 dB.
Parameters Thiele-Small:

Z=1000:
Re - 771om
Fs - 53.17Hz
Vas- 48.3L
Mms- 13.21grm
Qms- 5.5
Qes- 1.726

Z=2000:
Re - 1483 om
Fs - 54.65hz
vas- 44.8
Mms- 13.44 grm
Qms- 7.713
Qes- 0.5358

In attachments, frequency response speakers with a nominal 2000 ohms, impedance, frequency response apmlitudno and THD speakers with a nominal 1000 ohms.
40-22000 Hz from a single 8"- not bad.
"In the regiment" 22,000 Hz and a 2000-ohm speakers!
Confirmed peculiar characteristic of the complex impedance. Very small increase with frequency, instead of the classic quadratic curve - almost straight sloping line.
 

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TFR8-800, №24, №25.
Thiele-Small parameters: DC resistance, Re; resonance frequency, Fs, Hz; Q-- mechanical, Qa; electric, Qe; complete, Qt; equivalent volume Vas. Frequency doubling of the minimum impedance F2z, kHz.
........Re, Оhm;....Fs, Hz;....Qa;.....Qe;.....Qt....Vas, l.
№24...596.........40,1.....11,0....0,54...0,51....64
№25...593.........42,4.....11,1....0,56...0,53....56
 

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TFR8-800, №26, №27.
Thiele-Small parameters: DC resistance, Re; resonance frequency, Fs, Hz; Q-- mechanical, Qa; electric, Qe; complete, Qt; equivalent volume Vas. Frequency doubling of the minimum impedance F2z, kHz.
........Re, Ом;.....Fs, Гц;.....Qa;......Qe;.....Qt;...Vas, л.
№26...1500.........61,9.....12,4....0,51....0,49....46
№27...1500.........59,3......8,9.....0,52....0,49....53
 

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Congratulations on an incredible development.

Much more so for such good results :)

That very even frequency response is to be commended in any full range speaker; getting it in a high Z speaker is going beyond the limits.

Just curious, what diameter wire was used to wind the voice coil?

Is it copper or aluminum?

Thanks.
 
A comment about high-Z speakers...

Some people like John Broskie says that a world needs is a good 100R (or so) speaker (see The Tube CAD Journal, Hybrid amplifiers , for example), basically related to OTL world. Even in this forum I've seen this comment several times.
But I say that the audio tube world need is a great 2000R speaker ;):D:) . No need for high-current cathode-emission-exaust OTL amps. Since here is proved to be possible to manufacture speakers like this, and with great results, why no single one "traditional" maker offers some high-Z model, besides the cost? :confused:
Interesting exercise, at least.
 
Thank you, DIYBras.

An option, is made of high-current cathode-emission-exaust OTL amps.
Preamp and two monoblock amplifiers "Cyrclotron 6P45C". One powerful tube in the shoulder. Without the case, on the chassis.
Load - 32 consecutive fullranges speakers of 4 Ohms.
A little over 100 ohms. 25 W power.


Measured the real emissions of several high-current tubes at 14.5 V.
 

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Full-range speakers 5 ", 200 Ohm. TFR5-1-200.
Sound coil 1 ".
Low inductance is also, characteristic.

F, КHz,......Z, Ohm, №1....Z, Ohm, №2
0,2...........205...............210
0,3...........170...............170 (Zmin)
0,5...........170...............170
1..............190...............190
2..............210...............210
5..............230...............235
8..............245...............245
10............255...............255
15............260...............260
20............270...............270
40............340...............340 (F2z)

........Re, Ohm;....Fs, Hz;......Qa;.....Qe;.......Qt.....Vas, l.
№1......160.........130.......4,02....1,35.....1,0......-
№2......155.........132.......4,05....1,47.....1,08....-
 

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Full-band speaker 6 ", 50 ohm.
Sound coil 15 mm. Outputs of the wire from the coil are ribbons.
In the amount of 32 you can combine the connection.
From sequential - to parallel.
Getting different resistance. Even 1600 ohms.

........Re, Ohm;....Fs, Hz;....Qa;.....Qe;.....Qt....Vas, l.
№1......39..........92........6,4.....2,6.....1,8....-


F, KHz,......Z, Ohm
0,2...........42
0,3...........42 (Zmin)
0,5...........43
1..............46
2..............54
5..............65
8..............70
10............73
15............75
20............77
29............84 (F2z)
 

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