zeppelin in the Audio Nirvana

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human.bin said:
he wrote: 'The big port bass reflex is tuned to about 65hz and has little information below that'

really such a big box and driver won't go lower??

than OB with a woofer will be the only chance... it will also give some better highs i think

I have a pair of AN10 drivers in the 2.8 (narrow) enclosure, with the 'big port'. Following some advice I picked up here at diyaudio, I've put a temporary tube about 5" long into the port (trying to get better-sounding bass).

The statement about 65Hz (cutoff) got me motivated to download some test tones from the Bink Audio Test CD and have 'a listen' with my AN10s connected to a gainclone-type chip amp- I suspect that the bass is a bit weak with my tube amp.

First impression: 30Hz is a lot lower than you might imagine!

At 31.5 Hz the port was blowing a good breeze and you could definitely hear/feel the bass. At 40 Hz there was a respectable amount of sound. At higher frequencies the apparent volume increased, but that may be more a function of my ears/brain than the actual physics. I didn't hear anything dramatic when the tones went from 60-63-70Hz. No doubt measurements with calibrated equipment would tell the full story, but that's not something I have available.

Cheers
John
 
freddi said:
hey GM - -here's a quick hand-held TS for stamped frame Super 10 - -tried to hold it steady and away from my body.........

Greets!

I've only measured drivers that were anchored to either a relatively massive workbench or custom made stand, though typically in an acoustically small room (not as small as yours) for low Fs drivers, so a small signal was required. For higher power measurements, I did them in a two car garage with the door up. Anyway, considering how sensitive small signal measurements typically are, it seems reasonable to me that hand held wouldn't be very accurate, but I'm not familiar with any of the woofer tester models, so it may be moot what with them being far more sophisticated than the simple set-up I had.

GM
 
VictoriaGuy said:
GM:
Thanks for the sims for the AN 10 and 12.

You're welcome! If Freddy's specs are accurate though, then the super 10 cabs will be way too small and not worth the time/wood to make them. :(

GM
 

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freddi said:
what Q's did you use for those AN MLTL sims?

For drivers with a <0.403 Qts, I normalize them to it to get to a Vb = Vas, Fb = Fs alignment.

If your specs are accurate, then probably all my designs are worthless and will add AN products to my 'buyer beware' list. I prefer/recommend large size cabs to allow plenty of specs latitude, but to be so far off that a generously oversize cab is way too small is gross intentional misrepresentation.

GM
 
human.bin said:

@GM: if considering only one sub to be in the middle what would be you suggestion? sealed, horn loaded, h-w frame? there is an interesting project on the Orions site for an open subwoofer, but i don't know what electronic the need... please give some more hints

This depends a lot on how low you want it play, personal preference, the room's effect, etc., so to go low at high efficiency you need either an expensive driver in a large, low tuned vented alignment or a multiple driver variant. As you increase the cut-off to limit size/cost, then sealed or maybe OB with EQ'd multiple inexpensive drivers is an option.

The driver's efficiency may be nowhere near the published spec though, in which case it won't be as costly, though amp power requirements will be higher.

GM
 
on the second time around - I held a four foot piece of 3"ID pvc to sit the driver's magnet on giving better support and Q's came in ballpark with the first run and this German test

http://translate.google.com/transla.../search?q=%2B%22audio+nirvana%22%2Ban10&hl=en

I didn't get Vas the way ti though it should be - 12.9 grams didn't meet WT3's criteria of 25% Fs shift - IIRC using 19.6g added mass gave Vas ~4.8 cubic feet which is higher than the German test -- they probably did it more accurately

outdoors with AN10 in 70l reflex tuned to 41Hz, there really wasn't any clear indication of LF peaking and the same box looked ok near a corner. I'd probably tune it a bit higher depending upon room location.- just tune it to where it sounds the "best" overall -

An externally hosted image should be here but it was not working when we last tested it.


AN10 in 2.5 cubic foot reflex tuned ~41hz outdoors vs large Advent - each on a barrel near a house wall
An externally hosted image should be here but it was not working when we last tested it.
 
That's pathetic. Do me a favor and verify the cab's net Vb and tightly seal up the vent and measure its Fb, then let's see what Novak's vented box formula for a Fb = Fs tuning calcs. This is a fairly fool-proof way to get a good alignment even with specs that are considered to be unsuited for a vented one.

GM
 
I'll have to put it back in the box, find some duct tape and scrap wood - might take a day or so - if mains power doesn't go out when an ice storm comes through - - theres quite a big of rise and HF on-axis energy - the phase plug is good and HF Le low -- this fellow used an aggressive tilt network
http://www.audiodesignguide.com/Nirvana/index2.html

going back to the German Super10 article, they picked 80 liters, Fb=43
AN10S_Simu_SPL.png
 
GM said:


You're welcome! If Freddy's specs are accurate though, then the super 10 cabs will be way too small and not worth the time/wood to make them. :(

GM
GM-
Don't worry- I'm not sawing wood for a while yet!

I'm interested to see how the 'discrepancy' in the specs all works out.
I did notice that the German group seemed to get a Vas very close to the AN published spec-93L vs 102L.
And I have seen the pic of freddi's lab setup.....
:xeye:

John
 
Absolutely! I assumed as much and why my suggested alignments are way too large by accepted T/S vented design theory, but they are still too small if Freddy's specs are representative as to how far out of spec they are unless tuned high like theirs, so why bother building mine if they can't be tuned lower with enough box efficiency? Indeed, according to a sim, my tall cabs tuned this high will require more stuffing to smooth it out rather than keeping it to a minimum as it's meant to do.

GM
 
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human.bin said:
great to know Nelson, looking further for you works!
can you give me some hints on how do properly set-up a cross-over network? will a gainclone 68w/ch 8hm do the job? and t-amp/SET on the AN?

So far I am getting good results in the 3 X 5 ob using 12 dB/octave
slopes for both low pass and high pass with the frequencies for
the bass adjustable from about 60 to 120 and the FR from 100 to 200
Hz. Both drivers are wired in-phase, and the trick is to find the spot
where not only are they flat at the crossover, but measured individually
they are each about -4 dB at the same frequency, and then adjust to
taste from there.

At the moment I'm working up the passive version of the crossover for
the AN 6.5" supers with the Eminence 15" beta.

I'm running 15 and 25 watt amps.

:cool:
 
freddi said:
I'll have to put it back in the box, find some duct tape and scrap wood - might take a day or so - if mains power doesn't go out when an ice storm comes through - - theres quite a big of rise and HF on-axis energy.......

Whenever....... I wish I could get back to building/measuring, but I'm starting to believe it's not 'in the cards' for me. :(

Well, it figures, the part you want to be grossly overstated is the accurate one.

Anyway, take care and hope you have some form of fossil fuel to keep you warm and to cook with if the power goes out.

GM
 
Usinng the 206 solo filter of Tony Gee makes the Nirvana super 8" in a blh balanced down to aprox 40Hz. No problems with any acoustic music (not including organmusic :)). Plays reggae, disco and drum´n´bass.

Filter components:

L = 1,0 mH air-core inductor min. 2,00 mm wire, R = 0,17 W (tolerance max 2%)

C = 2,42mF MKP polypropylene foil capacitor (2,2mF + 0,22mF) – LeClanché, Audyn Cap Plus or Mundorf Supreme Cap (tolerance max 2%)

R = 10 W /10 watts metal film resistor (tolerance max 2%)

An externally hosted image should be here but it was not working when we last tested it.
 
Sounds like things are going pear-shaped for you again Greg. Sorry to hear that. :sad:

Ditto on the weather front Freddi -hope things improve PDQ for you.

Looking at those German specs. in the link Freddi provides, about the best I can figure WRT the Super10 in a box is a pretty vast (and mediocre) MLTL tuned to 25Hz, but needing 5ohms in series to do it & a fairly severe toe-in.

CSA = 363.75in^3 (call it 24.25in x 15in WxD),
L = 56.5in, Zd = 23.875in, Zp = 53in, vent = 5in diameter x 1.0in long, 0.25lbs ft^3 in the top 35in, then each adjusted to individual requirements.
 

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