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JTR Captivator - Page 133

post #3961 of 4725
quick question....is there a quick way to determine impedance on a passive cap without opening it up? in other words, can you use a multimeter on a speakon? I (obviously) know very little about these connectors redface.gif
post #3962 of 4725
Yes you can use a multimeter. Mine read 2.2 ohms iirc.
post #3963 of 4725
Quote:
Originally Posted by MKtheater View Post

Quote:
Originally Posted by desertdome View Post

In the DCX2496 software and the EQ section you can choose low shelf, high shelf, or parametric EQ filters. What MKTheater is using is the low shelf filter. When you enter the filters in directly using the unit's front panel controls, the EQ section says LP, HP, and parametric. It has them labeled wrong and really should say LS and HS instead of LP and HP.
MKTheater is choosing the LP filter, but is using a low shelf filter.

Correct, I forgot it was a shelf filter for a second. You choose(for EQ) LP, BP, or HP. BP is the normal parametric EQ. You can roll off highs, boost highs, and the same thing for lows. He has a little wiggle room(+/- 3 dBs to maintain a flat curve) so he can boost the low end where 10-20hz will be close to that top of that range and now 5hz will end up within that range making his graph now flat to 5hz. His 10-20hz range will be hotter but still within a FLAT region. Flat does not mean a straight line, it means a range. When I boost the low end like this to bring up 5hz it feels much stronger in my room and the need to run hot is not needed anymore. That is just me.

Should I be concerned with a loss of headroom if I boost my ULF below 20Hz? Also will the amps even handle this boost?

Thanks.
post #3964 of 4725
I'm getting ready to integrate a Velodyne DD-15 with a soon to be arriving Captivator S2. I'm hoping by corner placing the DD-15 I can smooth out a ~80hz dip in my main (1st) row of seats. Obviously the S2 has substantially more output capability than the DD-15 so my questions are:

1) Should I level match or gain match the subs for this scenerio?
2) If I should gain match... where should I position the mike relative to the S2 to get the best results since it is a dual woofer design?
post #3965 of 4725
Quote:
Originally Posted by dlbeck View Post

Should I be concerned with a loss of headroom if I boost my ULF below 20Hz? Also will the amps even handle this boost?
Thanks.

I am sorry I don't remember but can you tell me what you are using again for subs and amps? Are thet CapS2's? How many and how big a room? It depends on how much boost you need. I will look at previous pages.
post #3966 of 4725
Nevermind, I looked on the last page and you are down 3 dBs at 10 hz and 6 dBs at 5 hz which is awesome BTW! I would add a LP at 20hz with a slope of 12dB/octave and 5 dBs of gain and then run another graph and see what it does. What you are trying to do is bring up the 5hz to be the minus 3dB point and the 10hz will be equal to or more than the 25hz. You have plenty of headroom to do this as long as you don't run 10 dBs hot which you will run out of steam fast down low. 20hz and above is a piece of cake at reference with JTR gear and I am sure Jeff made these sealed Caps for a reason!
post #3967 of 4725
Quote:
Originally Posted by dlbeck View Post

Should I be concerned with a loss of headroom if I boost my ULF below 20Hz? Also will the amps even handle this boost?
Thanks.
You rarely loose headroom with EQ. I would think the amp should be fine. It would be cool if Jeff could change the DSP on the amp for you.
post #3968 of 4725
Quote:
Originally Posted by desertdome View Post

You rarely loose headroom with EQ. I would think the amp should be fine. It would be cool if Jeff could change the DSP on the amp for you.

I bet he could add the shelf himself but you would need to know the room gain profile of your room to do that.
post #3969 of 4725
Quote:
Originally Posted by MKtheater View Post

I bet he could add the shelf himself but you would need to know the room gain profile of your room to do that.
I believe the amp on the S2 is made by SpeakerPower and the DSP isn't user configurable.
post #3970 of 4725
I know Desertdome, I was just saying if someone really wanted flat to whatever they could measure their room gain profile and Jeff could have speakerpower input needed DSP and EQ so when they put it in room they are already flat to said number!
post #3971 of 4725
Quote:
Originally Posted by desertdome View Post

You rarely loose headroom with EQ. I would think the amp should be fine. It would be cool if Jeff could change the DSP on the amp for you.

Really? Doesn't 6dB of boost at a given frequency require 4 times the power? Wouldn't that would mean he will lose amplifier headroom because: 1)The amps in question (4000 watts) cannot quadruple their output on a dime (12,000 watts), and 2) Due to point #1 the amp's input gain would need to be reduced in order to maintain said boost, and doing that means a reduced power level for the rest of the frequency range. Since an amplifier cannot simply quadruple it's output on its own, you would naturally decrease the input gain, which reduces the output level across the entire frequency. Boosting that low is generally not a good idea. You can do/try it, but you're asking for trouble. I wouldn't do it unless I had an "uber" amp.
Edited by Nuance - 10/3/12 at 8:43am
post #3972 of 4725
Quote:
Originally Posted by Nuance View Post

Really? Doesn't 6dB of boost at a given frequency require 4 times the power? That would mean he will in fact lose amplifier headroom because: 1)The amps in question (4000 watts) cannot quadruple their output on a dime (12,000 watts), and 2) Due to point #1 the amp's input gain would need to be reduced in order to maintain said boost, and doing that means a reduced power level for the rest of the frequency range. Since an amplifier cannot simply quadruple it's output on its own, it will naturally attempt to decrease the input gain, which greatly improves the possibility of clipping. It also means an increased possibility of burning out the voicecoil on the drivers. Boosting that low is generally not a good idea. You can do/try it, but you're asking for trouble. I wouldn't do it unless I had an "uber" amp.

I think he was referring to the headroom above 20hz not the boosted 20hz and below. Anyways, the quadruple of power you mention is the reason multipe sealed subs are used with lots of power. If a movie requires -10 dBFS at 10hz(105 dBs at 10hz) you can figure out what you need. Depending on room a single Cap S2 may accomplish this and duals for sure.
post #3973 of 4725
Quote:
Originally Posted by Nuance View Post

Really? Doesn't 6dB of boost at a given frequency require 4 times the power? That would mean he will in fact lose amplifier headroom because: 1)The amps in question (4000 watts) cannot quadruple their output on a dime (12,000 watts), and 2) Due to point #1 the amp's input gain would need to be reduced in order to maintain said boost, and doing that means a reduced power level for the rest of the frequency range. Since an amplifier cannot simply quadruple it's output on its own, it will naturally attempt to decrease the input gain, which greatly improves the possibility of clipping. It also means an increased possibility of burning out the voicecoil on the drivers. Boosting that low is generally not a good idea. You can do/try it, but you're asking for trouble. I wouldn't do it unless I had an "uber" amp.

No you do not lose headroom. That is the wrong way to think about it really. EQ does not change the maximum amount of voltage or current the amplifier can supply, it also does not change the speaker sensitivity or driver displacement limits. Basic EQ neither increases, or lowers maximum output. So while 6dB of boost requires 4X the power relative to the same volume level as before the amplifier is still capable of the same maximum power as before. You haven't weakened it by boosting, note that the output was increased by 6dB by the EQ so there is a reason for the increased power demands. What EQ does change is the spectral balance of the signal sent into the amplifier and the system output relationship relative to the gain controls. All that it means is that the amplifier will run out of power in the boosted area earlier. It has essentially been turned up in that range and is operating closer to its limits than earlier. As long as the amplifier and drivers are matched right in the design there is no increased risk of damage to the drivers. I don't follow what you are saying about the gain. It is not like as soon as you plug a signal in the amplifier is immediately asked for maximum output all of the time and clipping everywhere. This is what limiters and compressor circuits are for. Any well designed system has this stuff covered six ways to Sunday.

Virtually every sealed powered subwoofer on the market is boosted below 40Hz. wink.gif
Edited by Ricci - 10/3/12 at 7:08am
post #3974 of 4725
Quote:
Originally Posted by Ricci View Post

No you do not lose headroom. That is the wrong way to think about it. EQ does not change the maximum amount of voltage or current the amplifier can supply, it also does not change the speaker sensitivity or driver displacement limits. Basic EQ neither increases, or lowers maximum output. What it does change is the spectral balance of the signal sent into the amplifier and the system output relationship relative to the gain controls.

Gotcha. So I phrased it incorrectly then; thanks for the clarification. So instead of saying it limits headroom, I should have said it limits output because you have to lower the amp's gain to avoid clipping due to the boost. Is that correct? So either way boosting does effect performance then, no?
Quote:
Originally Posted by Ricci View Post

Virtually every sealed powered subwoofer on the market is boosted below 40Hz. wink.gif

Yup, I know this. We're talking about adding extra boost using the DCX2496 with a suwboofer that likely already has boost applied below 40Hz.
Edited by Nuance - 10/3/12 at 7:20am
post #3975 of 4725
EQ does not lower or raise maximum output at any specific frequency range. Do not think of EQ in respect to affecting maximum output. Just get that out of your head. A lot of this disconnect comes from thinking of frequency response and maximum output as being the same shape. It is very rare that this is the case unless there is NO EQ shaping used for the basic frequency response. Maximum voltage limited output by frequency almost always closely tracks the raw acoustic response of the system.

The amplifier and speaker limits do not change with EQ. The basic response shape does and is forced into something other than it's natural shape by modifying the signal sent into it.

Think of EQ as affecting how close to the speaker and amplifier limits you are operating. Or put another way you are using EQ as a frequency specific volume control separate from the main volume controls. Take a look at how the frequency response of commercial sealed subwoofers change as the volume level is increased in the tests. The response eventually morphs into the raw response of the unit without EQ and you can see where, what shape and how much boost is being used in many cases. The area with EQ boost meets the amplifier and speaker limits first and starts to compress, limit or clip meanwhile there is still headroom left in the regions not boosted. Any time that EQ is used you have to expect this type of behavior where certain frequency ranges will run into the limits first.
Edited by Ricci - 10/3/12 at 7:35am
post #3976 of 4725
Quote:
Originally Posted by Ricci View Post

EQ does not lower or raise maximum output at any specific frequency range. Do not think of EQ in respect to affecting maximum output. Just get that out of your head.
The amplifier and speaker limits do not change.
Think of EQ as affecting how close to the speaker and amplifier limits you are operating. Or put another way you are using EQ as a frequency specific volume control separate from the main volume controls.

Right, I get that. You said system output is changed relative to the gain controls, right? So with that said, how likely is it that dlbeck will need to lower said gain to ensure he doesn't clip due to the extra added boost? I understand what you're saying, but I'm looking for an answer here. It was implied boosting at 20Hz will have no negative effects. Everything I've read on every forum (including this one, but specifically HT Shack) says otherwise. So which is it?

Lets say dlbeck does need to reduce amplifier gain because of the boost. Would that not result in a reduction of power to the rest of the frequencies? You're the master here, so please advise.
Edited by Nuance - 10/3/12 at 7:45am
post #3977 of 4725
See above you caught me editing still...

You know Audyssey and the other auto EQ schemes often do all sorts of things to the response including adding boost below 25Hz through overall volume recalibration. wink.gif How is this any different? Commercial sub manufacturer's have to provide a lot of protection for their subs because they never know what sort of craziness they will be subjected to. I'm sure that Jeff has done his homework. Not to mention that his products are probably a little more capable than most to begin with. Now if you have a giant pro amp run wide open on some drivers in a DIY setup and you haven't done your homework things could get expensive if you aren't careful with the boost (Otherwise known as too much amp for too little driver).

All that the boost will mean is that at the same master volume as before, the sub will be operating closer to its maximum capabilities over that particular boosted frequency range, when there happens to be content in that range in the material. When or if dlbeck's subs get pushed to the point where they are out of rope in the boosted region Jeff's protection circuits will intervene and clamp the output at that point, if executed well you won't even know it has happened.
Edited by Ricci - 10/3/12 at 7:53am
post #3978 of 4725
Quote:
Originally Posted by Ricci View Post

See above you caught me editing still...
You know Audyssey and the other auto EQ schemes often do all sorts of things to the response including adding boost below 25Hz through overall volume recalibration. wink.gif How is this any different?

Yes, I know, and it isn't any different. I never implied it was. I am asking what negative effects it could have, which we already established was reduced system output relative to any gain adjustments needed to prevent clipping in the boosted region. I mistakenly referred to that has headroom, which is my bad. smile.gif I've edited my original post as not to add to the confusion even further.
Quote:
Originally Posted by Ricci View Post

All that the boost will mean is that at the same master volume as before, the sub will be operating closer to its maximum capabilities over that particular boosted frequency range, when there happens to be content in that range in the material. When or if dlbeck's subs get pushed to the point where they are out of rope in the boosted region Jeff's protection circuits will intervene and clamp the output at that point, if executed well you won't even know it has happened.

Thank you - that is what I wanted to know. So there is an adverse effect to boosting that low, which is lowered output in the event you have to lower the gain on the subs. That was my point, and that's all. Everywhere you go on the forums the "gurus" say boosting down low is a bad idea. You've done a very good job of explaining why people say that. Thank you.

You still playing in your band?
Edited by Nuance - 10/3/12 at 8:43am
post #3979 of 4725
Thanks, Josh, for saving me from having to again discuss EQ and headroom. smile.gif You really need to add this to Data-Bass in either the bass myths section or the articles section. There is quite a bit of misunderstanding and it seems to come up weekly in various threads.

Nuance, there is more discussion about EQ and headroom in this thread starting with post #33.
post #3980 of 4725
Quote:
Originally Posted by desertdome View Post

Thanks, Josh, for saving me from having to again discuss EQ and headroom. smile.gif You really need to add this to Data-Bass in either the bass myths section or the articles section. There is quite a bit of misunderstanding and it seems to come up weekly in various threads.
Nuance, there is more discussion about EQ and headroom in this thread starting with post #33.

Thanks. I know how EQ works but mistakenly used the term headroom. That term gets used a lot in the wrong context, and I am as guilty as the rest. With that said, you can see how easy it is to get confused and assume that EQing limits amplifier headroom at the specific point of the boost; just read various threads on this forum and you'll see that terminology used frequently. Anyway, it's still a tricky scenario boosting down that low IMO, and the results will depend on many variables. My advice is to proceed with caution.

Personally, with the in-room response David has I wouldn't bother. However, if necessary then I'd make a couple cuts between 20 and 50hz to bring the overall level down to the same level as the ULF's; then I'd increase the gain or subwoofer output level to compensate. YMMV and to each their own.
Edited by Nuance - 10/3/12 at 9:38am
post #3981 of 4725
Quote:
Originally Posted by Nuance View Post

Thanks. I know how EQ works but mistakenly used the term headroom. That term gets used a lot in the wrong context, and I am as guilty as the rest. With that said, you can see how easy it is to get confused and assume that EQing limits amplifier headroom at the specific point of the boost; just read various threads on this forum and you'll see that terminology used frequently. Anyway, it's still a tricky scenario boosting down that low IMO, and the results will depend on many variables. My advice is to proceed with caution.
Personally, with the in-room response David has I wouldn't bother. But to each their own.

He was curious so I said try it and decide for himself.
post #3982 of 4725
Quote:
Originally Posted by MKtheater View Post

He was curious so I said try it and decide for himself.

I understand that, but caution should be advised. Guess that's what you have me here for. wink.gif
post #3983 of 4725
Quote:
Originally Posted by Nuance View Post

I understand that, but caution should be advised. Guess that's what you have me here for. wink.gif

I think he has 4 18's in a small room, at reference this should be no problem. He is already showing great room gain which helps out a ton.
post #3984 of 4725
Quote:
Originally Posted by MKtheater View Post

I think he has 4 18's in a small room, at reference this should be no problem. He is already showing great room gain which helps out a ton.

Agreed. I think his response looks fantastic, and I am not knocking the subwoofers (they are flat out sick), but rather than put in a filter at 20Hz and risk clipping, why couldn't he add a couple cuts between 20 and 50Hz instead? What are the negative effects of that vs. boosting at 20Hz?
post #3985 of 4725
Quote:
Originally Posted by Nuance View Post

Agreed. I think his response looks fantastic, and I am not knocking the subwoofers (they are flat out sick), but rather than put in a filter at 20Hz and risk clipping, why couldn't he add a couple cuts between 20 and 50Hz instead? What are the negative effects of that vs. boosting at 20Hz?

He could, but I found adding that LP at 20hz was much easier than figuring out the Q, gain, and frequency for 20 and 50hz because you can create dips.
post #3986 of 4725
Well DD and I were both at the GTG at his house. As far as I could tell he has headroom available for some low end boost. I was also there when Jeff was using that 4000 watt amp on a single ported cap. The driver ran out of excursion several times and he said the driver would not be harmed/can take some abuse.

Once desired boost is applied and system setup is complete, this is when testing with 5 star bass movies can begin such as WOTW or HTTYD. Since boosting low end, watch driver excursion and playback same scene increasing volume 3db each time. Once you are out of driver or amp, increased driver excursion will not happen. You will then know what max main volume level is within safe boundaries for the most difficult movies, and therefore safe for all other movies. If this happens before your desired listening level, then reduce boost.

One mans cut is another mans boost.
post #3987 of 4725
Quote:
Originally Posted by Nuance View Post

Yes, I know, and it isn't any different. I never implied it was. I am asking what negative effects it could have, which we already established was reduced system output relative to any gain adjustments needed to prevent clipping in the boosted region. I mistakenly referred to that has headroom, which is my bad. smile.gif I've edited my original post as not to add to the confusion even further.
Thank you - that is what I wanted to know. So there is an adverse effect to boosting that low, which is lowered output in the event you have to lower the gain on the subs. That was my point, and that's all. Everywhere you go on the forums the "gurus" say boosting down low is a bad idea. You've done a very good job of explaining why people say that. Thank you.

Sometimes it is a bad idea other times... Like anything else it "depends". Boosting a PR, horn or bass reflex subwoofer below it's corner = really bad idea. Boosting a sealed sub with a sharp high pass filter built in= pointless. Powerful sealed sub with a shallow roll off and no evidence of a sharp filter in the low bass= maybe worth a try at least.
Quote:
Originally Posted by Nuance View Post

You still playing in your band?

Yep. Mixing album #2 currently. All DIY.

Quote:
Originally Posted by desertdome View Post

Thanks, Josh, for saving me from having to again discuss EQ and headroom. smile.gif You really need to add this to Data-Bass in either the bass myths section or the articles section. There is quite a bit of misunderstanding and it seems to come up weekly in various threads.
Nuance, there is more discussion about EQ and headroom in this thread starting with post #33.

I'll add it to the to do list...tongue.gif
post #3988 of 4725
Guys,

My S2 is also scheduled to arrive in a few days. Can't wait to play with the new toy smile.gif

Is anyone here using a tactile transducer (such as Buttkicker LFE) with a high-end sub like Submersive or Cap? Do you think it will add a lot of value? My primary usage is movies.

Also, I haven't decided what to do with my existing sub (an Epik Legend). I could try to add it with the S2 for LFE duty to smoothen the response but I doubt that it could keep up with the S2 (and it has a sharp roll off at 20 Hz). Alternatively I could add it to my surrounds (Def Tech BPVX) and let it handle 20-80 Hz. My mains and center already have built-in subs (Def Tech 2000TLs and CLR-3000).

Thoughts?
post #3989 of 4725
First thanks for all the input. Good info for us non-experts.

I'm just looking to get the best all-around performance from my dual S2's in my 4800 cu ft room. I love the subs the way they are but always strive for the best. Many of you have said you would leave it alone. What benefits will I see if I boost below 20Hz and don't have to reduce my gain? Worth a try using a minidsp or 2496?

I'm taking the subs up to Jeff's shop in a couple weeks to correct a slight issue that Archaea and Luke discovered during the GTG. So perhaps he can make some adjustments while he is reprogramming the DSP. Thoughts?

a2u6uheg.jpg

David
Edited by dlbeck - 10/3/12 at 6:23pm
post #3990 of 4725
Sorry to dumb down the conversation, but I am wondering what JTR charges for shipping a captivator? Is it already included in the price? Perhaps I'm missing it on the website or maybe it's location dependent, but I'm coming up empty.

Thanks!
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