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

I got a pair of JTR RS1s (18” sealed subs) a few weeks ago to replace a pair of JL Audio E112s and I have been very impressed with the JTRs. I am using a pair of JBL 4367 speakers and a K235 active crossover from Sublime Audio with a 60hz high/low pass (24db slope). Updated pictures are in my profile.

 

 

The Sound for 2ch:

 

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 was not sure if I would notice the lower bass extension of the JTRs over the JLs for music but it is very noticeable and luckily adjustable on the JTRs with the Low Frequency knob on the back. There is about 8dB of adjustment between 20hz-30hz. At first the low bass sounded odd to me as I was not used to hearing it. I used the adjustment to cut the frequency. But as I adjusted, I turned it back to flat. I think this is intend for boundary reinforcement adjustments but is a very interesting tool for 2ch. After a week of tuning by ear I broke out the mic and measured the room and bass through the crossover was totally flat. Room modes of course still in tack with a peak at 90db-110db in my room but otherwise flat. I believe this 90-110db peak is caused by my low ceilings interaction with the 4367s as it was also there on my Revel 228be.

 

All said and done changing out good subs for better subs is not as big of a change as switching speakers but has made a bigger difference than changing electronics.

 

 

The Sound for Movies:

 

I am 99% music, but my room is setup as a home theater (all black, 120” screen, etc) and I bypass my home theater through my two channel system. The left and right RCA inputs in the subs can be used for both movies and music (the two channel is through balanced cables). All speakers are high-passed at 60hz and the LEF comes in at 80hz.

 

Anyway, I don’t have too much to say other than the power and low reach of these subs is crazy. My room is 26’X30”X8’ and I leave the back doors open to other rooms which extends the listing space to 42’. At reference volume (85dB speech, 105dB peaks) I worried about damaging the house and I am not kidding. I have no way to measure bass under 20hz with my current meters but there are scenes where I don’t “hear” the bass but it is felt and the doors flap.

 

Other items:

 

The build is very much like pro speakers with good but no thrills build. They are covered in spatter paint like a guitar amp. No issue for me in my black room but could be an issue for some.

 

The built in low pass crossover only goes down to 60hz so these IMO will mandate a high-pass on the mains at minimum for two channel. It does not go low enough to rolling in under a set of towers without a high-pass of some kind. You could add an external lower pass only I guess.

 

There is also no “phase” adjustment but there is a knob marked as “delay” in MS. I honestly don’t know how these compare as I did not need them to integrate using an active crossover.

 

They add no hum to my system which the JL’s did with their poor quality amps.

 

As a side note I am pleased with the Sublime K235 too and I will make another post about it. It is a good alternative analogue option. The K235 allows me to home theater bypass through it by using balanced for my 2ch preamp and RCA for my home theater as both inputs are active.

james633
james633 OP
1,026 posts
 

m-db

The only built in frequency adjustment on the sub is a manual low effect control adjusted by a knob. It adjust the slope from 40hz-10hz by about 8dB and has a surprising large effect on the sound. Audioholics discusses it in their review linked below (has a graph of full cut and full boost). I believe the sub they reviewed is the older driver and the current RS1 come with a new driver from the RTJ (not a typo) 18Sub which Audioholics also reviewed. 
 

when JTR talk about DSP I assume they have a non adjustable filter in the amp that forces the sub to play lower/flatter but I don’t know. They are very short on information. The measured group delay is 10ms at 20hz and only 5ms above 40hz.  Where something like SVS SB16 with built in user adjustable filters has a group delay is 90ms at 20hz and about 10ms above 40hz. Some say this delay does not matter in the bass as the waves are so long but I would disagree. If you are time aligning then digitally no issue regardless but I am using simple analogue slopes.  
 

 

james633 OP
1,026 posts
 

Mijostyn,

 

I have followed your system over the years and it has always looked impressive, I am sure it sounds amazing. 
 

SHD studio is an interesting idea. It would also allow for Dirac on the source side. 
 

I ordered a few more cards for the K235 and will try some higher crossover points soon. 

phusis's avatar
phusis
1,204 posts
 

@james633 --

Finding the right way to implement your subs will be a trial and error process. Your JTR subs have a DSP section built in already, and your JBL 4367’s are passively configured. Have you tried running your mains full-range and then just blend in the JTR’s via their DSP with a bit of overlap to where JBL’s start rolling off? Yes, I know you won’t take advantage of high-passing the JBL’s, but introducing a less-than-stellar DSP on top of your passive JBL’s isn’t ideal either, as you’ve found out, and so I would simply start out by leaving your mains alone and concentrate on moving those JTR’s around to where they integrate the best with the smoothest response, and top it off with delay and volume adjustments. I’d be inclined to position the JTR’s as close to the JBL’s as possible, but it mayn’t be the best way to go about it all things considered.

If you want to consider high-passing the JBL’s you need a quality DSP. I use a Xilica DSP/digital crossover (now re-branded ACX, but other than that they’re the same product and built the same place) which is an excellent pro line product and fairly priced. Yes, it involves A/D to D/A conversion steps as there’s not digital input, but don’t worry about that. Trust me, it’s a great DSP and sonically transparent. The Xilica/ACX DSP’s offer a vast array of filter settings far beyond those found in most all-in-one subs, that only have the most rudimentary dittos.

If you want to go a substantial step further I’d replace your 4367’s with their pro oriented siblings, the JBL M2’s in active configuration via the recommend Crown iTech amps with built-in DSP. I’m assuming the Crown DSP will be able to high-pass the M2’s, and then add a pair of JBL SUB18’s with an additional external iTech amp and be done with it. I’m not familiar with the DSP section of those Crown amps, but I take it they offer fairly elaborate settings that will eclipse those offered by the JTR DSP.

With the combo of the M2’s, SUB18’s and a trio of Crown iTech’s you’d have yourself a fully active setup (i.e.: sans interfering passive crossovers) with quality outboard amps and DSP’s that would take the sound of your setup to the next level. You’d be able to juggle with crossover frequencies, delay etc. to best accommodate your needs in ways you couldn’t now, and not least looking at each speaker channel of main + sub as an integral part and not a pre-existing main speaker with passive crossovers where the sub of a different brand and driver type needs to be "latched" on with a different, built-in amp and so-so DSP. Don’t underestimate the importance of using the same amps from top to bottom - including the subs, which most never get to experience since most subs house built-in amps.

Yes, the latter option will be the most expensive route, but hey, sell your existing McIntosh amp, 4367’s, K235 crossover and other gear and have it part-finance your new endeavor :)

Lastly: if I'm not incorrect the DSP filter topology applied with the M2's through the iTech's is with 36dB/octave slopes, which is what I use myself in my fully active setup. Moreover, some M2 users EQ them down low to extend to close to 20Hz, but that design natively is tuned to not much lower than 35Hz and so this is asking quite a lot more of its 2216Nd woofer. By high-passing them instead at, say, 80Hz or more you're doing the exact opposite by adding substantial headroom and making for a cleaner, more effortless reproduction. Win-win. 

james633 OP
1,026 posts
 

Phusis,

 

Thanks for the detailed thoughts.

yes I have tried rolling in subs under my mains at 37hz with my JL but not the JTR (internally their low pass stops at 60hz) and ran it that way for a month or so. It sounded fine but lack the impact on kick drums that highpassing brings. I am very happy with the current solution. I am sure it could be better by having the same exact driver/amp but I personally have not heard a better sub system as of now. I will try some higher crossovers not that I feel I need them but a few people who I respect have recommend them. Most of the time after messing around I end up back at 60hz.

Sadly crown amps are not the last word in fidelity and I think they hold the M2 back as I find them a little harsh. More or less Harman gives you a file to load into the crown amps with the needed PEQs and then you can adjust from there. The stock M2 filters are much different (much brighter) than the tuning of the 4367s. Erin’s audio corner has measurements of both if you’re interested. I would just end up filtering the M2 to match the 4367 as I like the built in “Harman curve”. The M2 replacement; the SCL-1 looks interesting. It has a passive network that can be 100% bypass to use active filters by the jumpers in the front. There is a silly deal on a pair “local” to me but I am pretty happy with the current setup.

 

james633 OP
1,026 posts
 

I have been trying a bit higher crossover this week. I am currently using 75hz and went as high as 120hz. I think the truth this with a proper crossover you can pretty much crossover at any point and get a good blend. The 18” JTR have more detail and weighty below 80hz. 75hz is a bit smoother (due to speaker placement?) and seems not to negatively impact anything. For now I will leave it and just get accustom to the sound. With acoustic and natural recorded music the subs are stemless. With music that is mastered in a studio with a lot of bass they are far less discreet lol. 
 

I am using a 24db slope. If I had an electronic crossover with a higher slope a higher crossover might work too as long as they stay out of the vocals. I personally don’t think the 4367 need crossover higher than 60hz. Higher just becomes a game or incremental gains. 

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