Jbl 4520 and altec 416

[NickH]

I'm building a pair of 4520 bass horns and I'm trying to figure out what drivers to use in it. I have pair of GPA 416-8b's and was wondering if they would work in the jbl 4520 horn.

I have to make this decision on how to cut the baffles.

I'm guessing they won't be a good match since the ts parameters are so different then the jbl 2205. But I would like someone's opinion with more knowledge in the subject then me.

Thanks,
Nick

[Lee in Montreal]

Hey Nick.

You want woofers with the lowest Qts you can find. Usually in the lower 20s. As it'll be used for home duty, you don't necessarely need high power woofers either. Interestingly the older 2205 had a much lower Qts than the following generation 2225 (which I have used) and lower "wattage". But trust me, you don't need high power woofers on a 4520. The cone will bearely move while the bass will hit you manly...

Get a driver that has an Fs of 35 or lower. The 816-C seems to be great. Qts 0.21 and Fs 22Hz. Power handling is "only" 75 watts though (versus 150w for the 2205 and 200w for the 2225) and Xmas is 4mm. You will get a great sound but don't play too loud at block parties.

[NickH]

Hi Lee,

Ya that the same thing I was thinking. Ive been using vas and qts as my comparison numbers. The numbers for the 416 are in the range for the qts but the vas is a bit higher. And the fs is lower so the cone is heavy. The 515 woulld also be ideal. Im thinking they should work but I wanted some opinions. Im not looking at much power. The 416's are rated at 150 program. I have them in my a7 at the moment and there insanely loud if I took it up to anywhere near 100 watts.

I going to try them with just one woofer first. I would rather have only one woofer per side. Im building the 4520's for the longer path and lower cutoff. The issue with using the altec woofer is that there 16" woofers. So once I cut the baffle for them theres no turning back , LOL.

Thanks for the info,
Nick

Hey Nick.

You want woofers with the lowest Qts you can find. Usually in the lower 20s. As it'll be used for home duty, you don't necessarely need high power woofers either. Interestingly the older 2205 had a much lower Qts than the following generation 2225 (which I have used) and lower "wattage". But trust me, you don't need high power woofers on a 4520. The cone will bearely move while the bass will hit you manly...

Get a driver that has an Fs of 35 or lower. The 816-C seems to be great. Qts 0.21 and Fs 22Hz. Power handling is "only" 75 watts though (versus 150w for the 2205 and 200w for the 2225) and Xmas is 4mm. You will get a great sound but don't play too loud at block parties.

[Lee in Montreal]

Longer path doesn't mean necerssarely "better". It depends on the style of music you like. I had 4530s too and could compare. If you like acoustic jazz, per exemple, and crave for the slap of the fingers on the strings of an acoustic bass, or the stick hitting the skin of the snare drum, you'll prefer a 4530 with its shorter path which is snappier. It happens that the sweet spot of the fundamental 1/2 wave is good for that type of music (80Hz). But if you want 10Hz lower, then the 4520 will give you that little extra bottom thanks to the 8ft horn (70Hz), but you'll lose some of the sound particular to the shorter 7ft horn. Pick your poison. The reason is that the upper cut-off where the phase cancellation happens is 150% of the fundamental (120Hz on a 4530, and 105Hz on a 4520).

[NickH]

HI Lee,


Ive read your opinions on it before. I think in the waldorf thread you menationed that. I listen to all sorts of different music. But I listen to very little jazz. I just cant get into it. My wife says its because Im a left side of the brain guy. But the big one is pipe organ music. I love pipe organ music. And with that the lower the better. After doing some hunting and digging Im thinking I will not put the 416's in these horns. I found the ts parameter given to me by the guys at great plains. The qts is in the 30's. Plus once I cut the baffle for a 16" driver im kinda stuck with it. Im going to stick with the standard 15" driver and cut out of 13 31/32". Ill have more options that way. Ive got 2 drivers to try in them at first. They were cheap pro woofers from parts express. There dayton. Ive bought a few of there drivers before and there not bad at all. I want to try and get some alnico 2205 frame and recone them in the future. Even though they will be aftermarket cones. Or theres always 2225's.

Ill probably find new homes for my gpa 416-8b's in the future when the time comes.

Nick

Longer path doesn't mean necerssarely "better". It depends on the style of music you like. I had 4530s too and could compare. If you like acoustic jazz, per exemple, and crave for the slap of the fingers on the strings of an acoustic bass, or the stick hitting the skin of the snare drum, you'll prefer a 4530 with its shorter path which is snappier. It happens that the sweet spot of the fundamental 1/2 wave is good for that type of music (80Hz). But if you want 10Hz lower, then the 4520 will give you that little extra bottom thanks to the 8ft horn (70Hz), but you'll lose some of the sound particular to the shorter 7ft horn. Pick your poison. The reason is that the upper cut-off where the phase cancellation happens is 150% of the fundamental (120Hz on a 4530, and 105Hz on a 4520).

[Woofer]

Longer path doesn't mean necerssarely "better". It depends on the style of music you like. I had 4530s too and could compare. If you like acoustic jazz, per exemple, and crave for the slap of the fingers on the strings of an acoustic bass, or the stick hitting the skin of the snare drum, you'll prefer a 4530 with its shorter path which is snappier. It happens that the sweet spot of the fundamental 1/2 wave is good for that type of music (80Hz). But if you want 10Hz lower, then the 4520 will give you that little extra bottom thanks to the 8ft horn (70Hz), but you'll lose some of the sound particular to the shorter 7ft horn. Pick your poison. The reason is that the upper cut-off where the phase cancellation happens is 150% of the fundamental (120Hz on a 4530, and 105Hz on a 4520).

I'd like to thank you, Lee, as you just answered a heap of questions I had about this same topic, but never got around to asking or let alone getting around to looking up.....
Excellent stuff.

Cheers,
Woof.

ps: I've got a pair 4530's with 2215A's in them that works OK although a bit wasted on that particular box with the inherent roll off which is (as you've explained) a bit short of the 2215's Fs of 20Hz. (or thereabouts)