giovanni56

Ar6 small speakers with big sound.

I first measured them and then replaced them; if in the measurement I had found values, at least on two instruments in the tolerance range of the component, I would not have changed them; by the way, such high capacitance values are difficult to measure correctly. Even the 470 uF Callins was totally "off."

"I have actually tried reflowing the solder in case it is a cold solder joint causing a loss of continuity, but nothing to say. They remain completely open. It looks more and more like the coil is shorted internally" If you measure open circuit it means that the coil is not shorted but is interrupted, at open circuit the ohm meter indicates nothing while at short circuit depending on the scale set in the meter some value should be read.

Yes, I had checked the graph in the magazine which has an impedance trend in that frequency range higher than 1ohm, as I noticed the minimum of 4.8ohm between 60 and 100Hz which I never measured in the three pairs I had available, I always measured minimums between 3 and 3.6ohm, in the graphs I posted the value is 3.2ohm. The first time years ago that I noticed that difference taken by doubt, I checked the speaker components, and everything was okay. Such a difference cannot be justified, unless, someone has let's say, "softened" that graph or made an unintentional mistake; you may have noticed that the impedance values on the vertical axis of that graph are reported manually, in my opinion whoever did it, probably entered the impedance values on the vertical axis by shifting a few positions. I can assure you that the measurements I reported are scrupulously correct.

Callins, they were out of specification, measured on three LCRs gave values from 4800uF to 5200uF, to be thrown in the puddle.

Very good explanation, thank you

Forgot: Many listening checks of the system for possible corrections and finally validation of the reproduction system made.

With the calculator, the results are obtained by applying the formulas that apply for resistive loads while the loudspeakers behave as reactive loads as a function of frequency; in addition, many other parameters are required for proper implementation of a crossover, e.g: the measurement of the impedance and T&S parameters of the transducers, the frequency response of the transducers, the nominal diameter of the transducers, the measurement of the distance of the emission centers between the speakers, the measurement of the offsets of the emission centers of the speakers, the resistance value R of the inductances that will be used in the crossover, the altitude and distance of the measurement microphone from the emission center usually of the midrange speaker for a three-way speaker, etc. etc. finally, good simulation software and a measurement system in a reverberant or anechoic environment (near-field measurement) to verify the frequency response on axis, at 30° and 45°. I see it difficult to make a good crossover with a simple calculator or table, partly because you could get a potentially critical load, getting a very low impedance with deadly phase rotations, for the amplifier to which you connect the system.

You're welcome Luigi. Looking at the impedance curves, I think the Ar11 MKI was with the switches set to 0db, as well as on the Ar10p but with the woofer control on 4p¬.

Ciao Luigi, the two woofers are Ar200003 that had the spider sagging, most likely the high Fs is not due to the foams I use, but to the treatment I did to regenerate them, the measurements were taken without any "break-in" after the refoam and the "respider," in similar cases after a good "break-in" the Fs averaged 19Hz.

Those tables give capacitance and inductance values that are derived as if the drivers were pure resistors, in reality the drivers have a resistive and reactive component that varies (by a lot, especially at the Fs of the component), depending on the frequency, so they give a very rough indication with respect to the correct values for making a proper crossover.

The measurements were taken with the midrange and tweeter switches at - 0db both and - 3db on the midrange and 0db on the tweeter, respectively. In my opinion the Ar11s are for certain amplifiers difficult to drive especially with the midrange and tweeter level controls at 0db, however, the frequencies of a music program between 1.8kHz and 20kHz, where the impedance decreases dramatically, have an average low energy content

Measurements before recap show a minimum impedance of 2.79 ohms at 57Hz, after recap of 3.25 ohms between 50 and 65Hz. The capacitors were all out of specification, especially those in the 2500uF impedance compensation cell on the woofers.

If it is helpful, I have weighed some mobile crews (cone+spider+coil and cone+spider+coil+foam), and the weights averaged 68 g without the foam and 80 g. However, when the whole moving assembly is installed, the foam and spider, in my opinion, add less mass than their weight, because the part of the two that is attached to the basket is not influential on the value of the total weight, to hazard a guess, perhaps the installed cone including the spider the coil and foam, will have a moving mass of about 72/74 grams, however, in T&S measurements, the Mms takes higher values, above 100gr, because of the contribution of the radiation impedance of the air mass that must move the cone and the mechanical impedance of the suspension (spider + foam).

In Italy, photos of a pair of Ar6s with narrow front edges and labels indicating production made in the USA have been published. This is the first time I've seen an Ar6 with US-made narrow front edges, I have a doubt that the labels have been reprinted and are not original, I think actually those Ar6s were made in EU. Can anyone in the group clarify for me? Ar6 with the thin edge were also built in the US?

Hi AR55, but these 20001311 are following 77/78

Was the tweeter of the Ar3a, Ar3a Improved Ar 200013-1 ever made with fluid iron in the air gap?

The drivers as has already been said are all original Ar, changing them with others, Dayton or any other, makes no sense. The 8" foams can also be found in Italy.

I would not change the dust covers, especially the creamy white oneswhich, if I am not mistaken, have a calibrated weight to achieve the desired resonance frequency.

How many grams of polyester acoustic absorber are in the volume of the Ar9 woofers? Does anyone know? are there any engineering papers that report this? thanks

Grazie, comunque se guardi da vicino, puoi vedere dalle foto del filtro che su una bobina c'è scritto 0.105 e su un'altra c'è scritto 2.85, presumo millihenry, mentre nello schema di Roy Allison per il triamping c'è un induttore da 2.6 millihenry mentre quello di 0.105 è assente. Che si tratti di triamplificazione sarebbe confermato dai sei terminali di connessione posteriori ma non capisco perché ne vengano usati solo quattro.

Traduzione I didn't know there was an account capacity limit. How do I delete that video file? I don't even remember what it is. Thank you, you have been very kind

Queste foto sono più definite.

???

I have doubts that Cello,/Levinson modified these Ar LSTs for the following reasons: 1) I do not recall Cello ever using externally wired midrange drivers and tweeters. 2) Cello used in the Amati, TNG/Ar tweeters with paper dome and fabric suspension, these pictured are the classic Ar with three-point suspension. 3) The label has a serial number that refers to early Ar LST productions and describes the six-position selector switch that is not present in these LSTs. 4) There is no plate or label indicating any Cello/ Levinson work on these speakers.