It looks like either he is serious about getting those 4pi sub measurements...

Or since he hasn't gotten the jet plane yet, he is going to try hang gliding or base jumping off of this?

Very interesting. Keep us informed of what you find out

hey, nice CB antenna!

Built at last. NO half measures of subwoofers with this pole I see. Ian had mentioned it would be over 70 ft tall. I'm interested how it will swivel and where the mics and power come from. Love his obsession with R & D and proper measurements! My kid thinks it would be great for bungie jumping too.

Ahh, and I thought it was the radio tower to call in emergency sessions of the Axiom owners club. I guess I'll have to put my secret members decoder ring away until later.

Cellular by Axiom.

I'm looking forward to seeing the pole on Friday. John Bridgman kindly lent me his QS8s for a few weeks and they really added to the atmosphere in my HT, so I'm picking up a pair then.

I think that thing in that photo is an example of giving the competition the "shaft". I wanna know who's going to be climbing to the top, and how he's going to do it. Or will it be you, Amie, who becomes a pole sitter.

John, Dennis told me you'd borrowed John's (Bridgman's) QS8s. I knew you'd like them.

HomieDad wrote:

Quote:

---

Ahh, and I thought it was the radio tower to call in emergency sessions of the Axiom owners club. I guess I'll have to put my secret members decoder ring away until later.

---

Does this mean there's no need for my Axiomobile? I just got a Tesla and painted it knotty pine. The Axiom decals and the big 80 were supposed to go on it this afternoon!

From that high up you should be able to see Iowa.

Axiom HQ is pretty much "downtown Dwight", very close to where the highways meet. It's going to be interesting walking through town while a subwoofer is booming away at the top of the tower.

"Honey, I think I hear a bear, get the kids into the car".

Hi Jack. Yes John and Dennis came over to check out my HT and suggested the QS8s would work better in the 7.4 system. I've had Totems all around and was using the Arros as side surrounds which sounded good with a more localizable side sound. John came back a couple weeks later to look over my screen/projector and we installed the QS8s beside the Arros for comparison. The larger airy soundfield made quite a difference to the illusion. I know most would not use small floorstanders for side surrounds but I liked the way they blended with the rest of the speakers. Anyway the QS8s are a definite improvement and they are seamless with the rest of the speakers which surprised me. I'd recommend them to anyone regardless of the make of their other speakers.

I'm looking forward to getting a demo from Ian on Friday on the new testing pole. I thought it was 72ft but we all know Ian doesn't mess around when it comes to measurement equipment so he built it 96ft high. Maybe it will double as an Axiom members only transmitter after all. My kid wants to bungie jump it and I'm having a tough time convincing him Mr. Colquhoun won't go for it.

I would hate to be the one placing and EP500/600 on my back and climbing that monster.

Post deleted in case Jakeman's kids read this forum

And for those who haven't received the Newsletter that came out today, Ian revealed the "secret" there.

How the heck did I get back here ? Hey, the newsletter points back to this forum thread

Quote:

---

Does this mean there's no need for my Axiomobile? I just got a Tesla and painted it knotty pine. The Axiom decals and the big 80 were supposed to go on it this afternoon!

---

You just know that MarkS is already hard at work with photoshop....

Ooooh! Is that a Trylon tower? They're Canadian-made and I have two of them in my backyard for ham radio! http://www.qsl.net/n8wrl/tower1.htm

73!

-Brian n8wrl

Well after several good conversations with Ian, Tom, Alan and Amie we went out back to look at the testing tower. Its always very pleasant spending time with them and getting caught up.

The tower sure looks like a good 100 ft up close. I had hoped to see a sub being tested but the wind had been picking up since early Friday morning as Ernesto continued its course up the East Coast. Nevertheless I did get a demonstration about the testing procedure.

Here is a shot of the weather instrumentation which goes up before every test. The temperature, humidity, barometric and wind readings are transmitted wirelessly to a metre inside the plant.



The environmental guidelines for successful testing seem to be temperature at no less than 10C, low to no wind, and average humidity. Humidity was not a factor I had given much thought too but apparently a high humidity testing environment can have an impact on results. I want to think about that one as it implies high water content in the air can affect wave propagation.

You can't see it in the above picture but there is a wire about 6ft over the platform which runs parallel. A Bruel & Kjaer mic is suspended over the sub or speaker equidistant from its drivers and ports. The mic can be moved along the wire depending on the subs configuration. Why a B & K mic? Its known to be one of the most accurate mics made and at $5,000 each it better be.



Anyway because of the wind, we just hoisted up the instrument cluster. The procedure was simpler than I thought. No winch. There is a pulley on top of the tower and another at the bottom. The platform is lifted by a 3/8" steel wire which is connected to a golf cart by a hook. Driving the cart backwards raises the platform to the desired height. The cart driver looks familiar.





The long distance of the tower requires a power boost and as a result of 100db appears to be the limit of reliable measurements. That's too bad as I look forward to seeing graphs at max output to get a better idea of the subs behaviour under stress. Perhaps a small generator at the tower itself would help matters. Here is a shot of the platform being lifted along with the electrical wires.


This finicky attention to detail and R & D just impresses the hec out of me.

Yes humidity is a bigger factor than I thought even in Cleveland. Knowing temperature and humidity you could use adjustment tables to get to a reference. As the air get moister, it becomes less dense(reverse of what I thought at first) and the speed of sound increases. It can make quite a difference to FR measurements or phase. I'm also wondering if that explains why my equalization settings appear miscalibrated on high humidity days.

Does this mean there is an equalizer with a humidity sensor in our future?

Good idea. I was about to buy a humidor for the box of Cohibas my brother-in-law brought back from Cuba -- maybe I'll hold off until I can get a combination humidor / BFD. Why buy two hygrometers when you can share one between the humidor and the PEQ ?

If you are so inclined here is a good article from AES on just how much these two factors can effect sound especially phase in a room. One conclusion is that it questions the usefulness of the auto-equalization feature found in many receivers.

http://www.rane.com/pdf/eespeed.pdf#search="environmental%20effects%20on%20the%20speed%20of%20sound"

>>>> In winter, you send us Alberta clippers and we send you a few choice words in return strongly suggesting you send your air elsewhere, thank you very much.

Jack, down here in our neck of the woods we praise the winter Alberta Clippers ... knocks the temps down into the low 70s / high 60s. Nice!

Quote:

---

Cananda? Candadian?

---

LOL! I sat here just saying them over and over laughing!

Forgot to use my spell checker. Humble apologies to all C a n a d i a n s everywhere. (Whew! Had to go slow, but got it right, I think.)

The noble people of Canadia thank you.

Thank you. WAIT A MINUTE! You're not Canadian.

Hoo wee, those cables, pullies, and golf-cart give me the willies! Getting heavy gear up and down a tower is a common problem for us hams - here's a nice solution for these kinds of towers: http://www.glenmartin.com/catalog/page10.html

No affiliation

-Brian n8wrl

My lovely daughter, who apparently inherited a family-wide affection for colorful and creative language, thought for a very long time that our neighbors to the north lived in Canadia.

You guys should try some air from the gulf of Alaska some time.

I never thought I had much of an accent, since my natural inflection is similar to the talking heads on network news. I was disabused of this notion some years later when somebody informed me that I sound like I am from the midwest (my parents are from Kansas).

Ever since I was very young - when I thought that emulating Pepe LePew's accent meant "speaking French" - I have been fascinated by the study of linguistic inflection. It can often be amusing to see just how long I can go while doing an impression of my dear Tennessee friend Dave, or one of my laughable (but respectful) characatures of our friends in the UK.

And yes, I always was fascinated by Rich Little. "Easily Amused" is a virtue.