Caleb Dick wrote on Sat, 08 January 2011 20:46 |
Did you try the subs clustered, or only singly? |
Evan Kirkendall wrote on Sat, 08 January 2011 19:32 |
The Triple 12 seems to roll off fast about 8k, and has a weird dip around 300hz, but is otherwise pretty flat. I ended up using 4 EQ filters total. EQ1: -3 @ 560hz, Q3 EQ2: -2 @ 5k, Q4 EQ3: -3 @ 8k, Q6 EQ4: +4 @ 9k, Hi Shelf Nothing too crazy. The box still seems to struggles past 12k, but it's not terrible. Listening tests: The cabinets do stay pretty clean and pretty smooth as you crank them up, but the HF struggles as you approach limit on the IT4000. Evan |
Jeff Permanian wrote on Mon, 10 January 2011 10:17 | ||
Evan There is definitely something wrong with your measurements. The Triple 12X is flat to 20khz... Jeff |
Quote: |
The cabinets do stay pretty clean and pretty smooth as you crank them up, but the HF struggles as you approach limit on the IT4000. |
Evan Kirkendall wrote on Mon, 10 January 2011 13:26 |
Jeff, I measured the horn on axis @ 1m, and ground plane at 1 & 2m. Evan |
TrevorMilburn wrote on Sun, 16 January 2011 05:14 | ||
I haven't used SMAART myself, so I am not conversant with the displays shown (I saw the 0dB in the display), but were the measurements taken at full power on the IT4000 or at 1w or some other power? I say this because the speakers IIRC are rated at 1600w program which means that if they were being given the full 2000w the IT4000 is capable of at 4ohms and had a 4db HF eq boost applied, the HF would be pushed well beyond it's comfort zone. I would expect most lesser speakers to be screaming for mercy or completely giving up the fight. Also, is it possible that the coaxial MF/HF was mounted in the centre position (it is a sealed unit so can be moved quite easily from what I have read elsewhere) and the measurements were inadvertently not taken on axis at all? Just curious. Regards, Trevor |
TrevorMilburn wrote on Sun, 16 January 2011 06:14 |
I haven't used SMAART myself, so I am not conversant with the displays shown (I saw the 0dB in the display), |
Mike Christy wrote on Tue, 18 January 2011 10:28 |
Very odd. I asked Jeff if the 2010 T-12 has the same HF driver as my T-8s, it does. My T-8 SMAART plots extended out past 12K, and I hear no evidence of a lack of high frequency from my T-8s. As a matter of fact in some rooms I need to pull 8k down a little for silibance issues. Maybe a bad xover part/solder joint? Mike |
Quote: |
Could be a driver, crossover, processor setting, or microphone issue. |
TrevorMilburn wrote on Tue, 18 January 2011 17:16 |
I for one would much rather see a reference to such problems as an addendum to a review... |
TrevorMilburn wrote on Tue, 18 January 2011 17:16 |
IMHO testers should report their findings to the manufacturer/dealer/importer before publishing just in case a rogue example has slipped past the post-assembly/despatch checks even if only to avoid embarrassment and with the hope that future quality checks are changed and/or improved. |
TrevorMilburn wrote on Tue, 18 January 2011 16:16 | ||
If the other speakers you guys tested measured OK, I myself would start looking at driver/crossover issues on the JTRs, or, as I alluded to earlier, the location of the mid/high driver. The results seem to be completely at odds with those of other testers (HT & high-end hi-fi) that I have seen who generally sing the praises of the fidelity of JTR products. I know I have worked with brand new equipment,AV/Computing etc. sometimes from manufacturers renowned for their stringent quality control, which has presented strange problems, not always immediately detectable to the naked ear/eye, due to manufacturing faults or other damage such by transportation is totally at odds with the usual production-run models. However, one has to accept that items sent out specifically for testing should be checked with extra vigilance before despatch simply to avoid such problems - IMHO testers should report their findings to the manufacturer/dealer/importer before publishing just in case a rogue example has slipped past the post-assembly/despatch checks even if only to avoid embarrassment and with the hope that future quality checks are changed and/or improved. I for one would much rather see a reference to such problems as an addendum to a review along with a response from the manufacturer stating what the problem was and what steps were being taken to prevent further such problems than read a belated, often grovelling response, after a review as been published and remarked/commented on by many of the reviewed equipment's target audience/prospective buyers when damage has already been done. Just my 2 Cents worth (Oh, and I have trained as an ISO/9000 quality auditor) |
Jeff Permanian wrote on Mon, 10 January 2011 10:17 |
Also, I'm in the process of making grills for the Orbit Shifter. Jeff |
Robert Patch wrote on Thu, 20 January 2011 13:09 |
Here is the measurement position for the 12x. |
Robert Patch wrote on Thu, 20 January 2011 15:09 |
Here is the measurement position for the 12x. |
Jeff Permanian wrote on Thu, 20 January 2011 17:09 |
Orbit Shifter: 2 watt so minus 3db for a 1 watt |
Steve Hurt wrote on Fri, 21 January 2011 12:39 |
That's odd. (The spec page) I thought my Orbit Shifter were 4 ohm. Have to check that. |
Steve Hurt wrote on Fri, 21 January 2011 15:04 |
If the SRX are rated in full space (and JBL sort of says they are) the difference in subs specs, and at the same time, similarity in Phil's measurements, would make a lot of sense. |
Art Welter wrote on Fri, 21 January 2011 18:29 |
I recently (finally) got to compare my dual LAB 12" front loaded sub to a JBL SRX 728 outdoors, either the 728 sensitivity is what it is claimed, or my subs magically gained 6 dB . |
Grant Conklin wrote on Fri, 21 January 2011 20:20 | ||
I'd be interested to see the results of that comparison. |
Art Welter wrote on Wed, 19 January 2011 18:00 |
But now I know the one watt one meter sensitivity of four front loaded dual Lab 12s is only around 98 dB, I want a pair of DSL TH -218, their sensitivity is 10 dB higher ! Art Welter |
Art Welter wrote on Fri, 21 January 2011 18:29 |
The SRX subs are not measured in full space, neither were Phil's measurements of either sub. His measurements of the JBL are within 2 or 3 dB of the JBL chart, considering his microphones are not calibrated or big buck, that is pretty close. |
Art Welter wrote on Thu, 20 January 2011 14:20 |
I have attempted to calibrate my Smaart readings, but am not sure if they are absolutly on. I have not attempted to calibrate them with the RTA 420 microphone I was using in the above test. I have written several times that I can’t get my 3 meters to agree at more than one frequency.. Art Welter |
Jeff Permanian wrote on Mon, 24 January 2011 09:02 | ||
Art, Since you've take quite an interest in my specs maybe you should take a look at other manufactures. DSL doesn't make a TH-218 but they do make a TBH-218, rated at 112db sensitivity, 2.83 volts, 2 ohms so minus 6db for a 1 watt sensitivity. |
Art Welter wrote on Mon, 24 January 2011 15:19 | ||||
Thanks for catching that mistake . The TBH-218 is too big, heavy, and physically too deep for me to want to use it, it's the size of four of my subs. I should have wrote "I want a pair of DSL TH-118, their sensitivity is 10 dB higher". The TH-118 is rated at 108 dB 2.83 v, so the four ohm cabinet is 105 dB one watt one meter, a pair 108 dB one watt one meter. One of my dual Lab 12 is around 92 dB one watt one meter from 40 Hz to 100 Hz, a pair is 95 dB, four (eight cones) is 98 dB one watt one meter. They won't win any sensitivity battles, but unlike most subs, can take full power down to their F3 without lots of distortion. Art Welter |
Jeff Permanian wrote on Mon, 24 January 2011 09:10 | ||||
Forgive me if I question the absolute level of your measurements and your correlated sensitivities. |
Phil Lewandowski wrote on Sun, 27 April 2008 14:48 |
Hey! Now that the weather up here in Cleveland niced up for me!! I was finally able to get outside and take some 1/2 space free air measurements on both the LA400 and the Growler! As a forewarning: These are not scientific by any means but I do think it really opens my eye to what EAW was measuring and I was impressed by how repeatable Jeff's data is on the Growler. This was a very nice and fun learning experience so any advice is welcome! My method: I placed the sub in an open field on my property. I measured 1 meter away from the sub pointed at it, on the ground. The SPL meter was on slow response C-weighted. I kept the sub not in use far away from the one being tested. I used a QSC RMX1850HD to power both. Both on channel one, switching from one to the other when each was tested one at a time. I fed a sine wave using Adobe Audition on a MacBook. I used a volt meter and used a sine wave to get an output voltage from the amp of 2.83 volts. (I just trusted that they are both nominally 8 ohms.) Of course, I didn't run it trough any processing. I didn't use a DSP either just to eliminate any chance of a variable. I went through starting at 150hz going down in increments of 10hz to 100hz. Then at 100hz down to 35hz I measure in increments of 5hz. Here is what I found: EAW LA400 It really enlightened me on where EAW got the sensitivity of 107dB. It seemed like they got it around 150hz. Which, I don't know many, if any live sound comps that cross there subs over that high! So the rating is really irrelevant! What I found is that the sensitivity in the range where the sub would be operating is something more like 102dB 1W/1M. Which puts the -3dB point at about 50hz and the -10 point at about 40hz. At least EAW seemed to get th -10dB point right on the spec sheet. Although it isn't -10 from 107dB. So the lowest usable frequency from this sub seems to be in the 45hz-50hz range and I think you can really hear that when listening! JTR Growler: This was very interesting because I believe for a spec sheet to be of use, the data should be repeatable. I was impressed by the "repeatableness" of Jeff's +-1dB from 110 to 46hz claim! (Especially with my setup) Also his -1 point was spot on with what I measured! When I asked Jeff about PEQ settings he said there was a hump around 140hz that I found. But he said, that I shouldn't have to bother with that since I am crossing the subs over much lower than that. I did find the -3 point to be about 44-43hz and the -10 point to be 36-37hz range. The sensitivity was right where Jeff puts it @ 100-101dB 1W/1M. So, I definitely give a big kudos to Jeff on really accurate repeatable data! In all, I hope this helps some people who wanted to see some real data on the 2 subs! Again, this was a learning experience for me and I loved it! Thanks & Take Care! Phil Lewandowski P.S. I am trying to figure out how to get everyone to be able to download the Exel file with all the measurements, since I can't attach it here! For now I will just make a make-shift table! It doesn't format well but the 1st column is the frequency, 2nd is the SPL of LA400 and 3rd is SPL of Growler. HZ LA400 Growler 150 107 103 140 106 107 130 106 107 120 106 104 110 106 101 100 106 100 95 105 100 90 105 100 85 105 100 80 105 101 75 104 101 70 104 101 65 103 101 60 103 101 55 101 101 50 99 101 45 96 98 40 92 93 35 88 87 30 N/A 81 |