At some point we compared (a panel of four guys) 3 different 18" drivers in that 35Hz horn sub depicted above - 18" Jensen FC, JBL 2241 and EVM 18 B. Each time I was able to hear the difference with Jensen field coil being the best, i.e. cleanest, most detail, life like, followed by EVM, followed by JBL. Difference between JBL and EVM was subtle, while superiority of Jensen was rather obvious.
What was the frequency range you compared, and slope of the crossover?
Did you match the level and frequency response of each driver, or just go raw response?
As far as the F3 on that Dayton...
In my experience a lot of the Dayton stuff spec-wise, how should I say this... exaggerates in their product's favor a bit?
I'd be surprised if in 1.7 cubes it's f3 was 40. I would feel a lot better if you could find someone out there's close mic response of it doing that.
Where as the TC I can vouch for. They are spot on with their parameters. If it says 53 at .79 cubes you can trust it. It is a better design and put together better IMO (it will stay linear under more stress). If you're using some EQ you can get them in the same ballpark and back to what weltersys just said about not telling them apart...
In my experience a lot of the Dayton stuff spec-wise, how should I say this... exaggerates in their product's favor a bit?
I'd be surprised if in 1.7 cubes it's f3 was 40. I would feel a lot better if you could find someone out there's close mic response of it doing that.
Where as the TC I can vouch for. They are spot on with their parameters. If it says 53 at .79 cubes you can trust it. It is a better design and put together better IMO (it will stay linear under more stress). If you're using some EQ you can get them in the same ballpark and back to what weltersys just said about not telling them apart...
the sub was driven by its own plate amp (Apex junior 250 W) with the x-over point set at 80 Hz. While there was some residual output, given that this was a horn, below 35Hz the slope dropped off rapidly. I understand what you mean by level matching. Again, spl was not something we were looking for, but detail resolution, lifelikedness. Other then that there was very little adjustment done. In a properly designed and built horn, field coil drivers produce superior sound across the board. As I mentioned before, my 80Hz mid bass horn is driven by 12" Rolla FC driver. If I could afford one, I would have 18" FC Jensen in my sub.
All manufacturers provided, should I say, optimistic data. Parts Express sells tons of Dayton Audio. If they were off by much, the rumint would
ve siad so. .79 cubes, but I already have a 2 qu ft box. Two per box?
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Below is the actual measured response of a pair in a 5 cubic foot (net) box, measured outdoors at 2 meters. Add 2 dB at 30 Hz to account for a microphone deficiency.
A single Lab 12 in a 2 cubic foot box would have a very similar response, just slightly less in the VLF- probably almost exactly the same response as pictured when the considering the microphone deficiency.
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That's what i initially had in mind...but then everybody started...you know, public pressure and all that...
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I'll throw my 2c in. Better drivers allow you to deal with system constraints better- but one can often outperform the better drivers by using more, less expensive drivers. I'll give you an example.
The Kaboominator Big bass in your place. Article By Jeff Poth
This system uses 2 isobaric pairs of drivers, in a force-cancelling arrangement, in the same cabinet volume as a single unit of the same driver would need, with the same sensitivity/efficiency/extension. Now, one could use a driver with the same TSPs except for higher power handling and Xmax, and achieve the same Xmax limited output, but it would require twice the excursion, the power would be dissipated across a single coil rather than 4, it would lack the force cancellation, and would not likely improve distortion performance (which rises with increased power/excursion). So 4 of the cheap driver, designed into the same size box, in all likelihood outperforms even some of the very best drivers.
Here's the kicker: the 12"s used are sold by the case (8) for $100, on clearance.They were $60 MSRP but are being blown out- they are nice, solid, but not feature-rich drivers.
So, for subs, I'd say that the design and implementation allow you to compromise quite a bit on driver quality and budget, while still meeting your goals. Higher frequencies impose additional limitations, you can't do an isobaric dome tweeter, for example, but in bass, where clean displacement is king, you can get a lot of the advantages a higher-end driver offers, by designing your system carefully around much less expensive drivers (which are not uncommon to find, and are often quite decent).
The Kaboominator Big bass in your place. Article By Jeff Poth
This system uses 2 isobaric pairs of drivers, in a force-cancelling arrangement, in the same cabinet volume as a single unit of the same driver would need, with the same sensitivity/efficiency/extension. Now, one could use a driver with the same TSPs except for higher power handling and Xmax, and achieve the same Xmax limited output, but it would require twice the excursion, the power would be dissipated across a single coil rather than 4, it would lack the force cancellation, and would not likely improve distortion performance (which rises with increased power/excursion). So 4 of the cheap driver, designed into the same size box, in all likelihood outperforms even some of the very best drivers.
Here's the kicker: the 12"s used are sold by the case (8) for $100, on clearance.They were $60 MSRP but are being blown out- they are nice, solid, but not feature-rich drivers.
So, for subs, I'd say that the design and implementation allow you to compromise quite a bit on driver quality and budget, while still meeting your goals. Higher frequencies impose additional limitations, you can't do an isobaric dome tweeter, for example, but in bass, where clean displacement is king, you can get a lot of the advantages a higher-end driver offers, by designing your system carefully around much less expensive drivers (which are not uncommon to find, and are often quite decent).
For readers that have the proper sized 2cuft sealed box for an 18" woofer.
The WinISD 2cuft sealed box bass SPL plots for the Peavey 479910=GREEN, 560600=YELLOW. A 20Hz Linkwitz Transform is used with a high power amp to obtain this response.
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great curves, great everything. Only one problem: 18" driver is completely out of the question.
As I said, my big 35 Hz horn sub had to go and I'm trying to replace it with two 2 cu ft sealed box subs.
I understand that, so I am asking why fiddle with the current two existing sealed subs? Sealed is pretty straight forward IMO, sure there are different levels of quality drivers, but unless they are junk or badly chosen for the cabinet there are no huge leaps in performance to be had by just swapping drivers.
Only if the SPL needs are modest (105dB peak). x-max is only 6.5mm, and x-mech is 13. Distortion is, however, low enough where the first sign of distortion you'll hear is the coil hitting the backplate. It's not that loud when it happens. It will NEVER get anywhere near the output of the 35Hz horn sub. I use the -01 version as the bottom end of a really nice 3-way, but it was a get everything else but sacrifice SPL design. As a sbwoofer, output would be on par with a $200 store-bought 100W powered unit - with much better quality. If that's loud enough, great. But going from a 35 Hz horn it's a big step down in output capability.
I do not agree.. I own a partial digital setup (CD + DAC) and a non-horn speaker-system (including a CB SUB). I can a sure you that your experience is not exclusive for horn systems.. nor for analog equipment.
Further the detail "grinding of horse's hear against the string" is not limited to the lower frequencies only... also higher harmonics are involved.
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