Infinity BETA 15" sutable for a tapped horn?

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I was referred here from hometheatershack because I was told horns are kore popular here so I'd get more help...

Hi Jim,

Here-is quick simulation that might be a :2c: start :

b:)
 

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Just 'running the numbers', this one is ~372 L net/700 w, though whether it's theoretical performance is worth the size/cost is up to you:

GM

The response of this one looks far better apart from the peakynees which can be fixed of course. 13 cubic feet doesn't seem awfully bad, I have heaps of room so there would be no trouble fitting it in. Is that 110db at 20hz? For the size and work involved would it be worth it in your opinion?
In the link it appears to be only a single coil Infinity Beta 15" Sub for sale - TradeMe.co.nz - New Zealand but on the site it says it is dual?
I'm guessing that this is the best response possible for it? Or close to best anyway.
 
Post #7

Hi GM just some quick questions:

1/4 wavelength of 17.6Hz gives me 488.6cm (192.4"). When you are referring to 17.6 Hz, that does mean the length from S1 to S5?

When you call it: "DTS concept - series VCs" does that mean that your simulation had two drivers in series, i.e.: 700 W into 16 Ohm, or a single of the dual voice coil models w/ coils in series, i.e.: 700 W into 8 Ohm?

I'm just asking for interest, the length seems correct for the peaks in your response plot. It may be important to point out that this does not reflect the low end performance at low power levels. I get a -3dB point of about 27 Hz, yours looks a little lower. Also, I cannot find any way to get something like a two driver DTS concept in 372 Liters; for a dual driver tapped horn (with throat coupling chamber) I get about 800 L w/ a -3dB point around 18 Hz (as always, that's net, no wood :)).

Regards,
 
The response of this one looks far better apart from the peakynees which can be fixed of course.

Is that 110db at 20hz? For the size and work involved would it be worth it in your opinion?

In the link it appears to be only a single coil .........but on the site it says it is dual?

I'm guessing that this is the best response possible for it? Or close to best anyway.

If you look at others sims Vs measurements you'll see that reality is a lot flatter in most cases.

The sim shows 115 Hz/700 W/10 mm Xmax/2pi and some say in reality it will be higher if I did the alignment correctly and the driver can handle that much power at low thermal distortion with a ~2.5:1 CR, which I seriously doubt. Still, it should easily drown out a similar size BR all the way up at least into the 90s.

Don't know, the Infinity site only lists it as a dual VC driver with the somewhat different spec 15X being a single VC.

For a given bulk, Fp AFAIK, though it can be made to go lower, bigger since its LF cut-off is down around 2.7 Hz, though with only 10 mm Xmax, not wise to tune it too low with just a single driver.

GM
 
Hi GM just some quick questions:

1/4 wavelength of 17.6Hz gives me 488.6cm (192.4").

When you are referring to 17.6 Hz, that does mean the length from S1 to S5?

..........or a single of the dual voice coil models w/ coils in series, i.e.: 700 W into 8 Ohm?

I get a -3dB point of about 27 Hz, yours looks a little lower. Also, I cannot find any way to get something like a two driver DTS concept in 372 Liters; for a dual driver tapped horn (with throat coupling chamber) I get about 800 L w/ a -3dB point around 18 Hz (as always, that's net, no wood :)).

Regards,

HR says 487.92 cm, but what's a few cms among friends? ;)

Yes, you make me wonder if I should quit listing it. ;)

Dual 4 ohm VCs in series per the linked owner's manual.

Mine implies a 22-23 Hz F3, though I expect (hope?) based on others sim Vs measured that it would be around 20 Hz based on the driver's ~94 dB efficiency.

I see I made a typo, the sim is ~335 L.. A dual is ~539 L, though of course in each case they can be expanded somewhat.

From this it's pretty obvious we have different ideas as to what constitutes a DTS concept and until I can get one built/measured I don't know if I have a clue or not, but the power sims are encouraging since I'm getting as much or more SPL in less/same bulk than with some other layouts.

GM

PS - I used his too except for a higher inductance, though I assume they're not very accurate, probably rendering all our musings mostly moot.
 
Hi GM,

Thanks for the explanations.

I think there is a lot of room for what may be a DTS concept :). I like to use a coupling chamber between driver(s) and throat, that's one obvious deviation. The total volume is so dependend upon the bottom cut-off point and shape, it's very hard to compare except model next to model, and then one would still have to build and measure. Oh well.

Regards,
 
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