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1 - Materials for Revision 3
Last update, 8/31/10: Frequency response tables for Rev. 3.2
Items 6) and 7) are in question and more circuitry will be added to control the timbral color |
| Output | Frequency | dB | Vout / Vin |
| Tweeter | 10 kHz | -3.13 | 0.70 |
| Mid | 1 kHz | -1.56 | 0.84 |
| Mid | 500 Hz | -4.53 | 0.59 |
| Mid | 200 Hz | +2.19 | 1.29 |
| Woofer | 50 Hz | +6.88 | 2.21 |
ORION Test CD frequencies (tracks):
| Output | Frequency (track) | dB | Vout / Vin |
| Tweeter | 4 kHz (5) | -2.81 | 0.72 |
| Tweeter | 1545 Hz (2) | -6.25 | 0.49 |
| Mid | 1545 Hz (2) | -8.44 | 0.38 |
| Mid | 400 Hz (3) | -3.44 | 0.67 |
| Mid | 100 Hz (1) | -2.66 | 0.74 |
| Woofer | 100 Hz (1) | -3.75 | 0.65 |
| Woofer | 40 Hz (4) | +9.69 | 3.05 |
Tips for balancing the ORION from Don Barringer
Check first, using pink noise from track 6 of the ORION Test CD, that left and right tweeters have the same output. Listen from about 1 m in front of each speaker, then bring up the level on the lower level tweeter. My hearing acuity for this test is very low, though Don reports that he could match his tweeters that way. I went with the assumption that both tweeters are very close because they came from the same batch rather than to trust my hearing for a match-up by this test.
After you turn on Orion-3.1 for the first time and everything seems to be working properly, you must search for the right tweeter level setting. It is not necessarily in the center of the tweeter level potentiometer. Tweeter sensitivity varies, possibly up to 0.5 dB, even under the tight manufacturing process control that Seas has implemented. With Revision 3.1 a 0.2 dB change (1 hour of the 7 am to 5 pm range) in potentiometer setting can be significant, especially when you are close to the optimum setting. The optimum could be between 10 am and 12 noon or 2 pm and 4 pm, for example due to tweeter sensitivity differences. Nominal is the range from 11 am to 1 pm. To find the right setting takes time and is not necessarily accomplished in one or two listening sessions. This is especially true for the woofer level since there is so much variability between recordings. So when you have found the tweeter potentiometer setting that seems optimum, live with it for a few days. Then increase the level by 0.2 dB (1 hour) and listen. Do you want to go back to your previous setting?
The volume control on your preamp controls the size and distance of the Auditory Scene. I use recordings with voices and instruments, orchestral and in natural settings like: Ramirez, Misa Criolla, Jose Carreras, Philips 420 955-2, or Stravinsky, Histoire du Soldat, Chesky CD122. You may want to play at ever higher volume levels because you do not experience strain or fatigue. But the AS can become too large and out of proportion spatially and in overtones. At reduced volume levels, when everything sounds neutral and smooth, you may lose aliveness that can be had at realistic sound levels.
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The tweeter potentiometer
has a level setting sensitivity of 0.2 dB/hour and a range of +/-1.0 dB.
The woofer potentiometer has a level setting sensitivity of 0.5 dB/hour and a range of +/-2.5 dB. A 0.5-inch diameter, though more costly, potentiometer provides better mechanical resolution and makes the adjustment setting easier to see. We use a Bourns Series 3345P potentiometer (DigiKey part number 3345P-102-ND). Tweeter and woofer levels increase counter-clockwise with this model.
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Sometimes you may want to know the frequency of a sound.
To match a pitch and find its frequency download the Virtual
Piano from Mike Marzalek's "CI Theory" website.
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0.1 | Revision 2 | Revision 3 |
CAUTION: The content of these pages may change without notice as I learn new things or find better descriptions. The designs presented here may change as I make new observations or gain more insight. I see myself as a seeker of truth, though I now know that every person is, and ultimately truth is a construct. There is only this. Maybe what has been done here points you to it. Audio has overwhelmingly been a hobby for me, for my own pleasure and love of music. I enjoy to share what I found and possibly to dispel a few misconceptions. My interest is not on the business side, though I like that my activities pay for my hobbies. You may not agree with some or all aspects of my designs, the approach that I take to them, or the theories. I have no problem with that. Just do not ask me "what would happen if ...". Changes that you make to the designs are for your own pleasure and at your own risk. But if you learn something worthwhile, then please let me know. I have received increasing amounts of email. I have responded to every legitimate letter that made its way through the Junk Mail, even when it meant repeating what has been published. There is an ORION/PLUTO Users Group with people who can help you. Go there first. I will still respond to every email, but you may get redirected. I consider my writings in these web pages as brief and to the point. I labor over every sentence and word and provide little redundancy. Read thoroughly and maybe more than once. I do not write for the rank beginner, but for those who have been around the block. You may need to study up. The links in my text are for that. You may find what seems like an inconsistency here and there. Look at the date of the page for when it was last updated. I am not going back over every page to bring everything on it up-to-date. I have not been standing still since I started this web in 1999 and with the idea of a brain dump of my previous findings so they would not get lost to the audio community, and with the PHOENIX as an example, so you could test my findings for yourself. In 2006, I thought I would go into a support and maintenance mode. No new design. Stuff happened, more enjoyment to share. Be forewarned, I am sowing seeds of discontent.
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