Is it possible to get chest-crushing bass with 8- 18 inch scoop bass bins or would folded horns or other bass bins give better response?

If you need bass below 50Hz, you really shouldn't try to use a small horn. Either use a larger basshorn or if size is a constraint, use direct radiating subs instead. A woofer that I am particularly fond of is the JBL 2245. It sounds very nice when installed in a 10 cubic foot cabinet tuned to 30Hz.

5 cubes, 2 4" diamter ports 12" long tuning 30 Hz for the tempest will give you amazing all around bass.

Adam

You will *not* achieve an f3 of 20 or 25 Hz like you can with a woofer like I mentioned with 99% of all home drivers, including lines offered by Eminence or JBL. I speak from personal experience. Maybe if you can afford absolutely giant enclosures they might work fine.

Most pro woofers run lower Q values and higher fs values to make them effecient. These are not exactly golden parameters for super deep bass response.

Kilomax 18's even in largish ported enclosures won't go flat to 30 Hz. You can get a tempest flat to 20 Hz and it has the excursion to handle it.

Adam

Sorry that should say 99% of all PRO drivers.

I'm not meaning to stir trouble, just my personal experience and my logic doesn't point to what you say.

Example
JBL 2226 15" woofer, optimum flat response, ported box
3.58 cuft, f3 of 53 Hz
7.7 cuft, f3 36 Hz
Adire Tempest
5.75 cuft, f3 25 Hz
11.5 cuft, f3 18 Hz

Adam

Another thing to consider is distortion. The electro-mechanical specs of a prosound woofer tend to make it more efficient, which means it doesn't have to be driven as hard for the same SPL as a less efficient woofer. They require less mechanical excursion, which translates to lower distortion. They are generally able to handle power better from an electro-magnetic perspective, which also reduces distortion and thermal compression. The best woofers use a Faraday ring, which reduces flux modulation, further reducing distortion.

All of these things put together can make a pro woofer 100 times better than a home woofer in terms of distortion. As an example, you can expect around 1% distortion from 50Hz to 250Hz when driven to 110dB/M in half-space when using a good prosound woofer like a JBL 22xx. Most woofers designed for home or car will have double-digit distortion at this point, and many will be at triple-digits.

First of all, scoops can produce chest-crushing, earthshakin' bass, which makes you feel sick. And they can do this better than any reflexloaded bin. But they need a suitable driver. For a horn (a scoop is a horn) a driver needs a very low Qts and a high Fs. Fs/Qts should be at least 120 , the higher Fs/Qts is, the better. Your Eminence Kilomax has a Fs/Qts=33/0.56 = 58

Your Eminence drivers are NOT suitable for the scoops. The best enclosure for these 18" would be sealed of vented. I you want to keep the scoops (I would, they can give great bassresponse) replace the Eminence drivers. It will be difficult to find the proper drivers for a good price. Best choice will be Precision Devices PD-184 (Fs.Qts = 107) or PD1850 (Fs/Qts=143). RCF L18P300 may also work.

By the way: it would have been a good idea if you had first invested what kind of drivers were needed for the scoops before buying them. Then you wouldn't have ended up with the wrong drivers in your cabinets.

Best regards,

Yes, pro drivers might be able to deliver better performance *if* you can use them in large cabinets or basshorns. I'd encourage you to keep an open mind though, because there is a lot of newer stuff out in the home department that you may not know all about yet. I'm not talking about stuff from Sony or something, I'm talking about true quality manufacturing that *does* have tight tolerances. These high excursion drivers really can do an incredible job at the lowest two octaves when placed in low-tuned and large ported boxes. I've found this out from experience.

I think we just have to agree to disagree on how much better a huge, horn loaded pro driver would sound over a more compact home speaker in a ported box which ultimately is engineered spcifically for that task, moreso than the pro woofer.

Adam

I would not recommend augmentation of the bottom octave by EQ because distortion is terrible. If you increase power under horn cutoff to bring the deep bass up, then the distortion products are what are amplified by the horn. The horn doesn't amplify the fundamentals below cutoff, but it does amplify the distortion products.

So my conclusion is if you don't have the room to build a proper basshorn, don't build a truncated one. A properly tuned direct radiating sub is better than a basshorn run under cutoff and EQ'ed to compensate.