ar_pro Posted February 8, 2017 Report Share Posted February 8, 2017 There's probably no absolute answer regarding the switch/resistor question; from personal experience with the AR-9 and powerful amplfiers in a large room, I've never been satisfied with anything other than a 0dB setting for the upper-range drivers. I've also run the speakers with the switches disconnected, and was unable to hear any repeatable difference when compared to a speaker set at 0dB. AR seemed comfortable recommending the use of tone controls (or simply, EQ, I guess) in lieu of the level-control switches in high-power/high-spl circumstances, ostensibly to avoid overheating the resistors. I've never encountered a flaming resistor board, but who knows, right? Anyway, these changes - along with alterations in room furnishings or the position of the speaker within the listening space would all be significant in their effect on the final sound, and certainly more than what might be expected by resistor or capacitor fine-tuning. As an aside, and because you seem to be especially sensitive & alert to slight alterations in the voice of the AR-9 and AR-90, but have you had a hearing evaluation recently? Regardless of age - especially regrettable in the case of young people - changes can be subtle or insidious, and even masked by the brain's ability to adjust to them. It's reassuring to know if everything's good, particularly for music lovers and people in this hobby. Link to comment Share on other sites More sharing options...
AR surround Posted February 8, 2017 Report Share Posted February 8, 2017 1 hour ago, ar_pro said: There's probably no absolute answer regarding the switch/resistor question; from personal experience with the AR-9 and powerful amplfiers in a large room, I've never been satisfied with anything other than a 0dB setting for the upper-range drivers. I've also run the speakers with the switches disconnected, and was unable to hear any repeatable difference when compared to a speaker set at 0dB. AR seemed comfortable recommending the use of tone controls (or simply, EQ, I guess) in lieu of the level-control switches in high-power/high-spl circumstances, ostensibly to avoid overheating the resistors. I've never encountered a flaming resistor board, but who knows, right? Anyway, these changes - along with alterations in room furnishings or the position of the speaker within the listening space would all be significant in their effect on the final sound, and certainly more than what might be expected by resistor or capacitor fine-tuning. As an aside, and because you seem to be especially sensitive & alert to slight alterations in the voice of the AR-9 and AR-90, but have you had a hearing evaluation recently? Regardless of age - especially regrettable in the case of young people - changes can be subtle or insidious, and even masked by the brain's ability to adjust to them. It's reassuring to know if everything's good, particularly for music lovers and people in this hobby. Thanks for the response on the switch/resistor question. I neglected to say in all of these discussions that when I turn around the couch and listen to the AR9's in straight stereo the best performance is achieved with the Tweeter at 0dB, UMR at -3dB and LMR at 0dB. Since first listening to digital sources I have always attenuated the UMR by -3dB. Anyone who has not heard the AR9 and AR90 in tandem would be shocked at how different they sound. It is quite obvious when sending a pink noise calibration signal around the room that these speakers have different voicing. It is difficult to understand given that both speakers have the same three upper range drivers and crossover components, but it must have something to do with the bass sections and cabinet dimensions. I need to edit my other post to make sure this is clear. Regarding the hearing evaluation...are you colluding with my wife? Link to comment Share on other sites More sharing options...
genek Posted February 8, 2017 Report Share Posted February 8, 2017 A hearing evaluation can be an enormous money saver. No point spending on sonic improvements you're not going to be able to hear. Link to comment Share on other sites More sharing options...
DavidR Posted February 8, 2017 Author Report Share Posted February 8, 2017 1 hour ago, AR surround said: ....................................Anyone who has not heard the AR9 and AR90 in tandem would be shocked at how different they sound. It is quite obvious when sending a pink noise calibration signal around the room that these speakers have different voicing. It is difficult to understand given that both speakers have the same three upper range drivers and crossover components, but it must have something to do with the bass sections and cabinet dimensions. I need to edit my other post to make sure this is clear................................. I had always read that the 9 and 90 were identical in sound except the 9 had deeper bass. So based on these two opinions I went and compared the two xover schematics (both taken from this site) for the LMR up. IF the schematics are correct there are some differences. (1) The UMR in the 90 shows a third coil (1.37mH) in the shunt position. (There is another 1.37mH coil with a 6 ohm resistor and 40uF cap and .2mH in series with the series cap on both 9 and 90). (2) The -6dB resistors in the 9 are larger in value. (3) It appears as if the 90 drivers are wired out-of phase. All else seemed to be the same. Perhaps someone else can confirm or correct this. Link to comment Share on other sites More sharing options...
AR surround Posted February 9, 2017 Report Share Posted February 9, 2017 48 minutes ago, DavidR said: I had always read that the 9 and 90 were identical in sound except the 9 had deeper bass. So based on these two opinions I went and compared the two xover schematics (both taken from this site) for the LMR up. IF the schematics are correct there are some differences. (1) The UMR in the 90 shows a third coil (1.37mH) in the shunt position. (There is another 1.37mH coil with a 6 ohm resistor and 40uF cap and .2mH in series with the series cap on both 9 and 90). (2) The -6dB resistors in the 9 are larger in value. (3) It appears as if the 90 drivers are wired out-of phase. All else seemed to be the same. Perhaps someone else can confirm or correct this. Yes, I now see that third coil, a 1.37mH job in the shunt position in the UMR crossover. That's very curious if correct. However, the attenuation resistors, while of different values within the two speaker systems, are wired differently to achieve the same results. The AR9 utilizes individual resistors for each switch position while the AR90 uses resistors in series to get the necessary values. For example, both the AR9 and 90 use 1.5 ohm resistors in the UMR circuit to achieve -3dB attenuation. However, for -6dB attenuation, the AR9 uses a single 4 ohm resistor while the AR90 switch adds a 2.5 ohm resistor in series with the 1.5 ohm resistor to obtain 4 ohms for the -6dB attenuation. Link to comment Share on other sites More sharing options...
DavidR Posted February 9, 2017 Author Report Share Posted February 9, 2017 I didn't realize the 90 put the 2 resistors in series for the -6dB position I always thought it was drawn wrong Link to comment Share on other sites More sharing options...
DavidR Posted February 9, 2017 Author Report Share Posted February 9, 2017 Actually it shows on this type of drawing for the AR9 UMR Link to comment Share on other sites More sharing options...
AR surround Posted February 9, 2017 Report Share Posted February 9, 2017 Note that the above AR9 drawing actually shows two 1.37mH coils on "Back Board - Item 3." So perhaps the AR90 schematic for the UMR crossover is correct and the AR9 schematic is wrong; and there are indeed two 1.37mH coils in both designs. Link to comment Share on other sites More sharing options...
NealXu Posted January 26, 2018 Report Share Posted January 26, 2018 Hi...i am a new user here. As per my knowledge it is only differences in their combined electrical measurements which can do that. Of course it makes sense to try and use brands which are reliable and will measure up well within their stated tolerances after the passage of time. buried vias pcb Link to comment Share on other sites More sharing options...
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