lower-mid horn design |
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roborg
Registered User Joined: 05 July 2004 Location: United Kingdom Status: Offline Points: 1026 |
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Actually those drivers do have a vented pole, the vent is mostly obscured by the aluminium plate at the back, behind the little bars. So technically i do have a leaky box, but it's not too much of a leak! In fact when driving hard there doesn't seem to be much air motion at all thru the vent (i hold a piece of tissue near it), so whilst it's probably adding a few losses to the effectiveness of the rear chamber, i think the good cooling is worth it. I've got to get smaart on the job to see how much of an effect the open vents have on the acoustics tho, my suspicion (and hopes ) are not too much....
cheers Rob |
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What I cannot create, I do not understand
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Timber_MG
Registered User Joined: 27 March 2004 Location: South Africa Status: Offline Points: 1454 |
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<>At low frequencies the rear chamber acts primarily
as a compliance and brings the resonant frequency of the speaker up to the
mid-band of the horn (ideally) as well as reducing interference of the
back-pressure from the diaphragm with the output of the horn. Dynaudio used to
have a resistive vent system called variovent (fancy word for leaky box).
Martin |
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RayVaughn
Registered User Joined: 20 August 2004 Status: Offline Points: 62 |
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Sorry - that plot was 2pi - here's the 4pi plot: I thought it looked too good to be true. Perhaps you could check I havent made a glaring error in the input params: The TAD has a Pmax (RMS) of 300w but they say 'rated power' 150w. The width of our bass tubes is 66cm so each mouth could be that wide. |
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Ray Vaughn and on www.innerfield.co.uk www.rocketfestival.com |
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Rog
New Member Rogers Archive Posts Joined: 23 March 2010 Status: Offline Points: 2166 |
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Hi Ray, Can you get me the other T/S specs, like Qts etc. |
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Rog
New Member Rogers Archive Posts Joined: 23 March 2010 Status: Offline Points: 2166 |
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Found the specs, Heres how my version of your horn looks. |
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Rog
New Member Rogers Archive Posts Joined: 23 March 2010 Status: Offline Points: 2166 |
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Hi Ray, The above plot is using your specs taken from Hornresp. I've done some modifications and have come up with this. Horn lenght 0.8 meters mouth 66 x 66 cm throat 350 sqcm rear chamber 15 liters front chamber 0.5 liters here is the lot and the expansion details.
Dist sqcm width angle 0.000 350.00 5.30 10.56 |
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Timber_MG
Registered User Joined: 27 March 2004 Location: South Africa Status: Offline Points: 1454 |
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*runs off to see how to get hold of AJ horn*
Rog, is GedLee's SPEAK any good taht you know of? Other recommendations for Horn-modeling software not listed in your FAQ? |
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Rog
New Member Rogers Archive Posts Joined: 23 March 2010 Status: Offline Points: 2166 |
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Hi martin, sorry for the late reply, I have been so busy these days. I've not used Ged Lees SPEAK, but I will try it now. I like AJ horn, for mid top its great and its predictions are good. So what you see is what it sounds like. Hornresp is good for bass, but I'm not convinced for mid or top horns. I also use Akabak with my own models of horns and chambers. This is the best way I have found yet. And no, I' can't send anyone the scrpits. Rog. |
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Timber_MG
Registered User Joined: 27 March 2004 Location: South Africa Status: Offline Points: 1454 |
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@ Rog: Thanks, I appreciate the time. Akabak *drool* is a "little"
pricey ... methinks AJHorn would be a good value then. The results
differ so greatly from hornresp it seems at high frequencies that there
is little point to do a mid-horn design with it.
@ Ray: Your diaphragm mass was given as 5 grams and hence you got the insane HF bandwidth . A sim with the T/S of Thielesmall.com differs significantly from Rog's AJHorn plot none the less. |
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RayVaughn
Registered User Joined: 20 August 2004 Status: Offline Points: 62 |
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That's the mass of the diaphragm on the manufacturers website. The cones a polymer graphite material. I assumed this is one of the reasons why the drivers are £300 each... http://www.pioneer.co.uk/uk/product_detail.jsp?product_id=14 74&taxonomy_id=43-203 |
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Ray Vaughn and on www.innerfield.co.uk www.rocketfestival.com |
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RayVaughn
Registered User Joined: 20 August 2004 Status: Offline Points: 62 |
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Thanks for this. Very helpful. I'll get AJ horn too and have a play. |
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Ray Vaughn and on www.innerfield.co.uk www.rocketfestival.com |
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Timber_MG
Registered User Joined: 27 March 2004 Location: South Africa Status: Offline Points: 1454 |
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A normal A4 sheet is 80grams per squre meter. That means that a 530
square centimetre cone would weigh in at 4.3 grams. The moving mass
includes things such as a voice coil and partly the suspension elements
in addition to the cone weight. I'd go with the weight of 53 grams
(which is fairly light).
Their compression drivers are even more "reasonably" priced but sound absolutely beutiful. |
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