JTR RS1s (18” sealed subs) vs JL Audio E112s, (JBL 4367)

@james633 wrote:

Overall, the JTRs are more detailed and textured than the JLs. They also blend better with the JBL 4367s much better than my JL E112s (also actively crossed over at 60hz). The JLs always had a bit of an over damped sound to me. That feeling of bass being from a sub and not a passive speaker, but they always sounded good regardless of this small issue. It was not until I got the JBLs with their amazing mid bass texture that I felt the JLs were lacking detail.

The JTR RS1 has a very light and nimble sound. More so than any sub I have heard. The driver even sounds/feels light when tapping on it with a light tone. When tapping on the JL driver there is a very dead low thump. I feel the 4367s outclass the JL for bass details, but I feel the JTR outclasses the 4367 for details and eclipses the JL. When actively crossed over the RS1s and JBL 4367 sound as if they are cut from the “same cloth” which is very surprising to me. To say I am impressed with their musicality would be an understatement and I never expected the end result to be so seamless.

I’m not at all surprised by your findings re: the JL Audio vs. your recently acquired JTR subs. The 4367’s have a dynamic and tuneful bass all around, and importantly they also cover the "power region" and further up to about ~700Hz, if memory serves me correct, which is a vital area (i.e.: 100-450Hz) and having a good deal of cone area here. With this kind of 15" woofer it provides for a fuller and more natural presentation compared to smaller and lower efficiency woofer/mids (that are often low- and high-passed in this region, if it’s a 3-way or more design), and this easily exposes the chosen subs solution to augment down low if too skimpy and low efficiency a variant.

I imagine a pair of JBL SUB18’s would only expand on the qualities that you have found with the JTR’s, except into the infrasonics, as this is a case of efficiency gained at the cost of extension; the SUB18’s wouldn’t impress the way the JTR’s do below 20Hz with movies, but from ~20Hz on up the SUB18’s would likely be the (even more) ideal match with the 4367’s. It’s a compromise and what to go with here. Myself I’d rather go for absolute coherency (and efficiency) and miss out on infrasonics, but when you have 25Hz flat delivered effortlessly even at bonkers SPL’s it’s quite another experience than what small cube subs do at the same frequencies. As I'm sure you know by now, the bass of the former is much more convincingly felt and perceived by comparison.

Where I’ve found the 4367’s to shift character tonally is in their lowest octave around the port tune where they become warmer and less defined, and this is likely the reason for your finding the JTR’s to better them here when the 4367’s are high-passed at 60Hz. I’d argue you could wring out even more potential here with a high-pass at 80Hz or a bit higher, in addition to intricate delay settings and room correction down the line.

The subs that needs finger pointing for their price isn’t as much JTR and to some degree the SUB18’s as it is the JL Audio’s and other "hifi" subs mentioned by you. Paying that much dough for the JL’s with amp failure all too frequent is simply laughable. For the same reason I would generally avoid subs with built-in plate amps and instead opt for quality outboard amps and DSP’s with more elaborate settings. This also opens the door for more all-out DIY sub options and would save you money.

Phusis,

Seem like good insight on your comments above.

I also set up the subs a few different ways before settling on the K235 crossover.

#1 I used my surround processor (Marantz) to crossover, time align the subs with my mains. I tried a number of higher crossover points (60-110hz etc) and still liked 60-70hz the best. The integration was good but with the processor on I felt I was missing something in sound quality. Hard to put my finger on exactly what it was. The system as a whole was just a touch less dynamic and maybe the sound stage was smaller. Could be just placebo on my part. With the processor in pure direct it does sound a bit better to me but the crossover are not active in this mode.

#2. I also tried a simple highpass filters from Harrison labs. This was a 12db slope at 70hz (I had to flip the leads on my speakers) and then used the subs internal low pass. This measured very flat across the frequent range, maybe even more stable than the 24db slopes but I felt like a bit of impact as missing where the drivers over lapped. I also found the volume of the sub ultra critical with this setup.

I might add room correction on the source at some point. I have not been real impressed with audyssey and almost always end up with manual adjustments. For 2ch at the moment I am not using correction and just moved everything around to where it measured/sounded the best…. Those two correlate by the way…

On a side note I will try some higher crossover points soon. I need to order cards (only $12) for the K235 as it does not have a variable adjustment. I “knew” roughly where I wanted to start playing in my system from past experience.

I sometimes feel like higher crossover points really could use super steep digital filters (48db) to keep the subs out of the low vocals. Something I have never really played with as most “highend” options are very expensive. Something cheap like the Mini DSP SHD would work (sound quality?) but really complicates my home theater with added delays due to processing and another digital to analogue conversion I really don’t want in my movies.

The Captivator page mentions the presence of digital signal processing. Lacking a published link, do they offer auto and or manual processing? 

Good for you using a full 2 way crossover. I would go a little higher if you can. 80 Hz would be perfect. It will lower distortion in the JBLs. Larger or multiple drivers of similar quality are always going to have less distortion because they do not have to move as far to produce the same volume. As drivers move farther the suspension becomes non linear and distortion increases. Another source of distortion is enclosure resonance and shaking. Turn the volume up and put your hand on the enclosure. Any vibration or shaking you feel is distortion. If you can feel it, it is clearly audible. This is a very difficult problem to solve and the only commercially available subs that do are the Magico Q series at ridiculous prices. I would never go larger than 18" drivers. As the cone gets larger it becomes harder to control and motion can become non pistonic, the cone starts flapping at volume. I use a total of eight 12" drivers. The main reason I use 12s is to keep the enclosure size reasonable. The enclosures are a custom balanced force design. They have a decagon cross section with 1.5" plywood walls. Plywood is stiffer than MDF, but much more expensive. There is no vibration or shaking. No enclosure resonance at all. You can see them on my system page. A photo diary of their construction will be available on Imgur. 

Digital crossovers are always better as long as the DACs are of good quality. The ones in the SHD are not, but the SHD Studio is the same unit without DACs. Benchmark Media Systems uses the SHD Studio with two of their own DACs with great success. I use a DEQX Pre 8. I cross at 100 Hz. A slope of 48 dB/oct keeps the subs out of the midrange. The key test is listening to the subs only with a male vocalist. If you can hear any vocal coming through the sub a higher slope is mandated. Always use the lowest slope you can get away with.