Collaborative Tapped horn project

[bjorno]

Originally Posted by 454Casull

The impulse response looks very poor and I can't figure out how to make it better.

IMO, Thats a layman's opinion based on visual interpretation of an IR that cannot be deduced without slicing up the response in pieces and that must be evaluated with psycho acoustical scales if to be of any value.

What's wrong with the IR?

b

[454Casull]

Originally Posted by bjorno

IMO, Thats a layman's opinion based on visual interpretation of an IR that cannot be deduced without slicing up the response in pieces and that must be evaluated with psycho acoustical scales if to be of any value.

What's wrong with the IR?

b

I don't have access to Hornresp right now but there is no positive portion to the waveforum, IIRC.

[bjorno]

Originally Posted by 454Casull

I don't have access to Hornresp right now but there is no positive portion to the waveforum, IIRC.

I've reached my limits for to verbally understand your sentence.

b

[David_Web]

If you look at this in-room measurement of my TH driven by a 2.1 amp based on LM something used in crapola devices.
http://img263.imageshack.us/img263/9861/ircompare.png

Where is the oh so bad IR from a TH?
Compared to an ideal Q0.577 simulated with a rolloff at 30Hz

Hornresps imported IR is not far of when lowpassed the same way.

The point is that you have to low-pass the IR to get anything meaningful out of it, else you are chasing ghosts.

[454Casull]

Originally Posted by bjorno

I've reached my limits for to verbally understand your sentence.

b

sorry

see attached

[Patrick Bateman]

Originally Posted by Puggie

After a productive morning reading this thread could someone be so kind to throw this driver into hornresp or similar, I'm currently Mac-ified and until I sort out my PC at home I cannot do much modeling

Overall diameter: 215mm (8.5-inch)
Sensitivity: 87dB (2.83V/1m)
Mms: 31.5g
Cms: 454 um/N
BL: 5.99 T*m
Voice coil diameter: 35.55mm (1.4-inch)
Impedance: 4 Ohm
DC Resistance: 3.4 Ohm
Fs: 40Hz (free air)
Qms: 7.35
Qes: 0.693
Qts: 0.765
Xmax: 8.5mm (one way)
Vas: 26L
Sd: 0.02 m 2

I'm looking for a relatively small tapped horn if possible, that can reach under 30Hz (20 if possible) I'm hoping a small footprint and tall enclosure will have sufficient WAF!

I have a couple of other options in 8" drivers if that isn't suitable (but reading this thread I hope it is).

I am running both Akabak and hornresp on Ubuntu using VMWare Player.

Seems like everyone is buying Macs these days, and I don't imagine that Akabak will ever get ported to OS X, or even Windows 7!

So VMWare Player is absolutely great for this stuff.

[Patrick Bateman]

Originally Posted by 4pyros

I dont think a tapped horn should be smaller just louder.

I'd argue it's the other way around. Tapped horns aren't necessarily louder than front loaded horns. They're simply a novel way to horn load a woofer without using a huge box.

IE, due to Hoffman's Iron Law the efficiency between the two is comparable, but tapped horns give us the luxury of making the enclosure smaller than would be practical with a FLH.

A few years ago I used to argue on this forum that the TH *was* more efficient, but I no longer believe that is the case.

Oddly enough, one could argue that a sealed box is superior for infrabass than a tapped horn. So a tapped horn's best place to shine may be the range from about 40 to 160hz, oddly enough.

[Lee in Montreal]

Originally Posted by Patrick Bateman

I'd argue it's the other way around. Tapped horns aren't necessarily louder than front loaded horns. They're simply a novel way to horn load a woofer without using a huge box.

IE, due to Hoffman's Iron Law the efficiency between the two is comparable, but tapped horns give us the luxury of making the enclosure smaller than would be practical with a FLH.

Front and rear loaded horns are designed around a 1/4 wave, while tapped horns use 1/2 wave. Therefore the tapped horn is theorically bigger. Ironically, the RLH has the peak resonance at its 1/2 wave. Basically, I'd say it's a cheat to say that RLH are based on 1/4 wave . Per exemple, a JBL 4520 has 1/4 wave at 35Hz, but the real bump (1/2 wave) is at 70Hz, where it has the highest output.

[GM]

Horns are 1/2 WL resonators same as an open pipe except with a 1/4 WL fundamental.

GM

[obeman]

B&C SPEAKERS

21IPAL
2500w (AES)
80 mm peak-to-peak
15..22mm linear peak
Flux Density 1.35
FS 37HZ

:O