JTR Captivator - Page 76

Every sub will reach its limits if pushed hard enough. At the KC GTG we had sub channel +6db and Jeff turned up the gain. At that point the sub was probably like 15-20 db hot and he was turning up the master volume, so at times it was probably up to 15db above reference on the most punishing subwoofer clips. Yes we found the limits of the sub including port chuffing, driver out of excursion, and rocking. It is the only time I have got to listen to the captivator. If Carp still wants the help swapping the drivers, we may do some sine wave testing on old driver before pulling it. Then test new driver to see if we can find the rocking in driver. Although he is probably getting around a third of the amp power that comes with the powered captivator so might not find much.

4000 watts/ 7200 watt burst is over twice as much as my entire theater runs on period. With the available muscle he has on the powered unit, it seems apparent to me that it has the ability to find the limits of the other parts of the system (driver, ports). Every sub will be limited by one of its components. It seems Jeff has built a fine system that is reaching its limits of power, driver, and box at about the same time with his all in one system. It seems Jeff is pretty confident in the driver abilities and says it is pretty much indestructible, so he doesn't need to be super aggresive with the dsp. If it has found its limits, turn it down a few clicks. I still believe that someone looking for a ported sub that excels at music and HT, should have the Captivator at the top of the list at its price points of either passive or powered.

Nobody knows the sub better than Jeff and if he says no hpf needed for your setup then it isn't needed. I say why not though with the many eq options that have one built in and you can always add later. It will lower distortion below tuning, be easier on driver, and save amplifier power not utilized below tuning for the usable bandwidth.

Yes the room can affect distortion measurements. Lets say a room has 20 db more room gain, it then has 20 db more output masking the distortion and giving it a lower distortion %. I would think this would be even more evident lets say from port chuffing on 20 hz tune where bass becomes more audible at certain output level. Just a few thoughts I felt like throwing out there.

WOW Luke I didn't realize you guys had it that Hot! Boy and i have been worried about having it 5db hot in my system I have a long way to go to max it out back to seeing what the limits are.

Absolutely, I want to test and compare as much as we can. I may need your help swapping them more than I though! I dislocated my shoulder (absolutely brutal experience in the ER by the way, and I'm surprised I'm not a heroin addict right now with how much drugs they were pumping in me) last Tuesday. It's doing VERY well all things considered, I have full range of motion and very little pain but I still have to take it easy for a few weeks.

Jeff told me he thought he would get my driver at the end of the month, so I'll keep you posted.

Sub level was increased for HT and then gains increased on both the Cap and Subm. They were both running really hot, not sure by how much. I thought their price difference with them above the others was evident in their performance. The cap was in your face awesome, and the subm was the only sub of the day to excite the individual pieces of an electronic dart board on archaea's door (lowest frequencies hit that day).

I don't know how the dsp is set by Jeff for sub at meet or any of the subs. I just know we found distortion at the GTG. It seems counsil isn't having his subm's distort like the one at the meet did either. Like stated before Archaea's room won, we turned all of them up louder than they should have, and left with our tails between our legs.

I am eager to see difference found for Archaea going from dual pb13u and yamaha pro sub to the dual caps, I think he can finally quit for a while! Loving the LMS 18" 5400 comparison, keep it coming.

Yeah, they were pushing those subs really hard because Archea's room is so tough you really had to have it cranked to get impact from the subs. To give you an idea, the fully powered Captivator hit 108 on Master and Commander at the seating positions and the passive Captivator hit 114 on the same scenes in my room at the listening position and I've always thought my room was very tough on bass!

Correct me if I'm wrong about that 108 Archea, but I think that's right. I know the 114 is.

That sucks, the ER is always bad news. How did you do that? I pulled my neck and can't turn my head trying to wakeboard all day last weekend like I was a teenager. Its a good thing its not coming now, we would look like Frankenstein and the Hunchback trying to swap that big driver!

even the BP-10's look tiny

I was playing sand volleyball for the first time in years (I use to play all the time in my 20's). My buddy gave me a perfect set and I figured I'd hammer one down pretty good. I did, but my arm tried to follow the ball I guess. Never done that before, not recommended!!

First round of max SPL tests: Peavey CS 4080hz in STEREO running a single Cap

EQ on the SMS is flat, and the front of the sub is exactly 12' from the RadioShack digital SPL meter on the couch in my normal LP.

15hz = 106db
20hz = 109db
25hz = 112db
30hz = 115db
40hz = error. I thought something bad happened because I started to hear this horrible vibration sound. SPL meter was over 120db. It turns out the Cap at 40hz actually moves itself across the floor!! The sub was originally 6" from the rear wall, and had moved all the way back to make contact with the wall. That was the sound. I moved the sub back to it's normal position and tried again. This time I watched the sub, and sure enough, at 40hz it started scooting towards the wall again!

you need a dual opposed cap

You are correct. We hit 116dB in your room on the dubstep music with the EP4000 bridged to 8ohm.
In my room with your same Captivator - we never hit over 108dB with Jeff's 4,000 watt amp - though I will state the captivator was noticably being pushed harder with the heavier duty amp at our G2G that it was on the EP4000.

Few things... room obviously... but also EQ - The built in amp probably either takes out peaks that might make that reading higher or kills up amp power pushing up nulls

I just talked with Jeff,

He is going to try to send out my Cap Pros tomorrow! Yahoo!

I talked to him about using a single EP4000 amp on the dual Captivators and whether I should use them in the common eight ohm config with the amp bridged mono making a 4ohm load, or use them wired to 2ohm each - one on the Left channel and one of the Right channel of the EP4000, using the Sub1 and Sub2 output on the Onkyo TX-NR1007.

The advantage of wiring them at 2ohm would be that my receiver has Audyssey EQ XT which seperately configures both subs, so I could potentially have better placement and sound for the subs in my room. The disadvantage potentially being more heat from the amp??? Others disadvantages?

Here is the EP2500's specs as tested by avsforum's chasw98 (these numbers should be the exact same thing as the EP4000 as the EP2500 is known to be rebadged to make the EP4000.)

Two Channel Two Ohm
http://www.avsforum.com/avs-vb/showt...7#post10755537

Mono Bridged eight and Four Ohm tests
http://www.avsforum.com/avs-vb/showt...5#post10755565

Which would you guys suggest? Does it even matter? As of our discussion Jeff was planning on wiring the Caps to 2ohm so I could use both channels on the EP4000 and make use of my receivers audyssey dual sub configuration functionality.



I also asked Jeff about the subsonic filter. He said it'd be nice to have one, but not probably necessary. He said try it without it first and see if you mind - he said I didn't have to fear damaging the driver with the amp I was using. At worst I might get a muddier sound on some clips with ULF below the tuning frequency. I need to research cheap subsonic filters...I like the price of the FMODs for $25, but the reviews are all over the board!?!?

I don't want to say those figures are "low", but I'd expect higher in-room "max" figures from it. Hmmmm?

James

Question on the RS Digital SPL meter settings.

Did you use the SPL C scale, Fast and MAX setting?

Yes, I'm using those settings.

I'm in the process of testing the EP4000 in bridged mode, and it's taking longer since the amp's internal breaker keeps popping.

I will say this though, the SPL meter at 15hz hit 110db before the breaker popped. The EP4000 is obviously more powerful in bridged mode than a single channel in the Peavey. Stay tuned!

Second round of max SPL tests: Behringer EP4000 in BRIDGED MONO running a single Cap at 8ohm

EQ on the SMS is flat, and the front of the sub is exactly 12' from the RadioShack digital SPL meter on the couch in my normal LP.

15hz = 110db
20hz = 112db
25hz = 115db
30hz = 120db

lukeamdman,

It'd be intersting to see the Captivator's spl number if rewired to run at 2ohm on a single channel of the EP4000 -- for selfish reasons of course (as you probably read in the post a few above that's the configuration i'm looking to use) I do understand removing and rewiring the driver to 2ohm isn't a simple fast request. But if you are bored and want to have definitive answers for the rest of us!!!

I assume these are uncorrected values? If so, numbers would need to be adjusted accordingly.

12Hz add 16.5dB
16Hz add 11.5dB
20Hz add 7.5dB
25Hz add 5dB
31.5Hz add 3dB
40Hz add 2.5dB
50Hz add 1.5dB


For 15hz, you could probably approximate 12.5db.

After adjustment, those number are looking very impressive.

How did you know when you were hitting max? Distortion? Clipping lights? Or did it just stop getting louder?

I've read so much crap on the RS SPL meter that I don't know what to believe anymore. Some say the newer ones are within +/-3 dbs while others maintain correction figures like yours (and some even more dramatic) are needed.

As I mentioned though, those numbers do seem low for "max" figures, so perhaps it is a bit "light" down low?

James

I'm definitely having problems with my cap. I can't figure out where the trouble lies - user error, equipment, etc. I've experimented over the weekend with different settings and placement of the sub. So far, a single/stock MFW-15 seems to be hanging with it performance wise (which I know can't be possible).

I hear distortion at the listening position around 103 db. With the meter in front of the sub, I didn't go over 105 db's due to distortion as well. Unfortunately, I don't have anything to run specific tests or sweeps. Maybe I need to learn and implement rew or something of the like pronto. I'm also really busy at work during the day, so I haven't found time to bug Jeff, to see what he thinks yet.

For equipment, I'm using a Denon 4311 with XT-32, MIC2200, and a Marathon MA-5050. I'm only using the 20 hz cut on the 2200, and I have the Marathon bridged.

Here are some pics of the room (please excuse the mess). I started with it next to the MFW's and then moved it up behind the screen. Of course any thoughts or ideas are always a welcome.

There is certainly something that isn't right going on there. I'd start by bypassing the 2200 and going right from the Denon to the Marathon just to see how that fares.

With the Peavey, I think the clip lights turn on before there's actual clipping. With the EP4000, clip lights didn't come on until a millisecond before the breaker in the amp tripped.

I can finally say I've achieve scary bass, even for me. The Peavey is bridged mode is, for lack of a better word, is insane. Before clipping, my dedicated 20A circuit trips. At that point, the bass is so loud I can't see straight and have a instant headache. I'm a complete bass head, so that's remarkable.

I do think I'm hitting the limit of my SPL meter though.

For example, the meter will be at 110db at 20hz. I'll turn the volume up, the house shakes more, the wind from the Cap blows harder, but the meter doesn't move. I'll go up even more, get more shaking, more wind, again, meter won't move.

Could the incredible amount of noise from the walls, ceilings, and doors be interfering with the reading?

BTW, still not a single sign of distress from the Cap, and I can feel the air it's pushing from 15ft+...and I'm standing behind a couch!

All SPL meters that use the SPL C scale require correction factors. Here is a sweep I made for a RS Digital SPL meter with the microphone removed. Follows the SPL C scale perfect.

Green line is SPL C scale.

Red line is SPL A scale.

You may be near the limits of the meter. Also wtch out for weak batteries in the SPL meter!







Yes, the SPL meter just measures what it "hears". It can not think nor is it frequency selective other than it measures everything inside the rather broadband C scale filter!

Cap Pro's shipping this week! Awesome! Finally going to give my pl380 a workout!

I suspect that your numbers once you apply the correction factors may approximate the useable limits of your Cap-amp system in your room. As you continue to attempt to raise the volume from there, your actual measured volume goes up very little, but there might be a sharp increase at that point of harmonic distortion which then causes other things to shake.

Those are measured numbers at 12ft from the sub are tremendous for a single subwoofer.

Thanks Mojomike for the idea. I just tried it and seemed to get about the same results. I tested Ironman's cave scene when he is first walking out (I think it's around 38min, 35 sec.) and I'm getting quite a bit of distortion and popping at 101 db's, main seat. It was shaking the walls pretty good, but definitely made me throw the volume back down fast.

Agreed.

I might add that single sine wave testing for max SPL levels is not a good idea. Too much unneeded stress on the equipment.






Yup, very good numbers in the intended subwoofer bandwidth.

Do you use a high pass filter on the subwoofer?