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Madaeel

BOSSOBASS Raptor system 3

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I wanted to say a couple things.  Bosso, that post about naked sealed subs is spot on and what most people don't realize.  When one LT's their sealed system it acts like a port but even better as it adds more down low where the ported will fall off and one can keep the box size smaller to do so!  I made a post on AVS to let people know that although the ported always wins on WinIsd, However, in the room with proper shaping there is no contest. I have been running my system as a 7hz ported sub because I never sealed my speakers openings and it created this 12 dB peak at or around 6-8hz.  I have been tinkering with different speakers to properly seal the openings when I decided to run a sweep and then run a scene. Well, the scene was much more powerful at the same level with the sealed system and then I ran a quick sweep to calibrate and here is what I got.

 

sub_zpsa7vholjq.jpg

 

This was a 75 dB sweep to calibrate with my speakers. 

 

Hi James,

 

I'm gonna hafta jack the thread for a bit and finally get to the bottom of your posted measurements and system. :P

 

Here are just 5 of the dozens of in-room FRs you posted over the years:

 

8e2f025364406a28b193883de3548832.gif

 

A room should be showing certain characteristics regardless of the native frequency response of the sub. I haven't seen that from your measurements. They're so all over the map that I couldn't ever nail down the pattern so that I could see the differences between different subs in the room with differing hardware roll off and power vs sensitivity, etc.

 

So, one of the FRs in the animation is of the so-called 7 Hz tuned ported IB and one of them is the newest sealed IB. Were they both with the same upstream hardware (pre/pro/amp)? Was EQ inserted on both or either of them? I can see that the levels were different. Can you repeat the last one with the level bumped to 95-100dB? Did you ever get SpecLab up and running?

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Actually all the above.  You are looking at 5 different sub systems, 4 different measuring mics and equipment, and 3 different LP's from that sequence.  It is hard to keep up with me for sure because I can't.

 

The dark blue response was the Omnimic with the chase subs(on concrete)

The one that says spl and phase was the IB with behringer mic(on concrete)

The huge peak at 60hz was the eD 13av2 system with RS meter I believe

I don't remember one as I would have to look through photobucket

The last one was my 12 SI's in a wooden riser and sealed wall using the Umik.

If I turn the gain up the 3-4 hz stuff changes all over the place but 5hz and above stays the same in response.  My mic is not accurate below 5hz.  My behringer mic and RS meter match up pretty good. My room has gone from 2047 cubes to 1460 cubes with all the risers and walls I have added.  I finally figured out a way to shut my doors during sweeps now as well.  I will have to dig up my 7hz ported type system as it was not present in the graphs you have shown.  I have not even begun to fine tune the subs yet as I am still finishing the wall.  The LT on my subs is much more powerful feeling than the ported versions anyway and I will be doing that, no ports.  Here is a new one to just to mess things up more.

 

Un eq'd full range response with the so called 7hz tuned(through holes around my massive speakers) using the Umik.  I love the Umik's ability to plug and play but this thing is not consistent, my RS meter stays linear and more consistent using just c-weighting which is probably too low. 

 

center_zpsfcfab932.jpg

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Yeah, James, I just don't get it. Granted, I've only had one measurement rig, but I've re-done the theater several times and placed the subs and mic infinite different positions. I once posted a graph with a dozen FRs taken over time from various place with various subs. Can't find it now, but the point is that they show variation, obviously, but they also show a lot more similarity than yours have over the years.

 

The last 2 posted graphs just don't jive. Post the FR that you think is the most consistent with your current system. ASnd, if you don't mind, post what the system is; amp, EQ, boxes and drivers.

 

THX

 

I just finished watching TAS 2 (Spiderman) and have found a whole new attitude of appreciation. This this is a ULF monster and the CGI is pretty awesome as well. I must not have been in the mood on the first run through. I have it in 3D and can't wait to check that one out as well.

 

Here's a minute and a half from chapter 14:

 

3ecPsWh.jpg

 

Tons of ULF down to 1 Hz. It's rated 4.5 stars, but that's due to a 4 for level. Bump the SW trim a bit and this one ranks with the best.

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I know Bosso, I am finalizing my final setup soon so I can really start getting consistent. Nothing stays the same in my room including the damn room! I just sold my speakers and now my baffle is wide open so I can even run the subs or it will be like free air.

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Wow crazy ULF sweeps I wish I liked the movie.

 

Just a comment on the content, both video and audio are 5 star in TAS 2. Subjectively, whatever floats your boat.

 

I've seen a lot of comments in the past year about near field placement and all sorts of comments about velocity, etc. Brandon has recently placed a couple of 18s near field, Pop placed that whopper 24" as a head rest, etc. Of course, subjective comments will extol the difference vs far field, but I haven't seen many measurements posted that show the radical difference in frequency response between near field and far field placements.

 

In my own case, I have done these experiments years ago and documented the difference. As I've always maintained that what we hear is primarily frequency response and everything else is secondary, it was no surprise to me to see the huge difference in FR and relate that to the listening experience differences.

 

a315a0d4744e1a07913e11546206016b.png

 

It's also difficult to calibrate a sub that's so close to the seats with one that is placed more traditionally closer to the satellites than to the listener. Look at Pop's posted FR. Folks are telling him to use EQ to tame the room modes, which, sorry but that was a bit funny to me. It's just the predicted result of placing a measurement mic close to somewhere between the port and driver of a big ported sub. IMO. If that sub were placed at 4M or further from the seat...

 

We saw the same result when Adam posted the FR of his near field SI 15s vs the far field Raptor. It's a pretty big compromise. Too big in my opinion, which is why I never used a near field placement, velocity notwithstanding.

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I think that Crowsons would be better for most people instead of near field subwoofers. Maybe just me but seems like most are using their near field to have more "feeling," in the subwoofer ULF region. So Bosso your 1-4m response sweep makes sense to me.

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Dave makes a very good point that the near field response greatly changes things and drastically reduces the low end relative to the top bass octaves.This could be equalized of course but I wonder how many are taking the time to flatten the response back out. I also wonder how many are level matching with the other subs or whether the near field sub ends up very hot. Localization also seems like an obvious issue.

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Even if they did flatten the response I'd imagine they'd be eating up a huge chunk of power to boost the low end with it being down so far compared to the subs farther from the seats.

 

Josh you still have the XXX's right? Do you use buttkickers and/or nearfield placement?

 

I know in my room down to 10hz I feel everything pretty good through my couch. Below that it's not as potent but still there. Still need that Oppo to boost the response because then I could without a doubt state the difference between Dave's room and mine since we'd have the same exact gear. Even without it though I don't need nearfield for anything above 10hz. I would never use buttkickers no matter the quality just because to me it's artificial. I'd build a riser before anything.

 

I will say Ethan uses my SI's I had behind the couch and before that an eD A7s-450 and localization never seemed like a problem amazingly. However, it was level matched to the other subs. I think someone mentioned in Pop's thread running the nearfield subs hot which I would think would make the experience more like enjoying a ride than a movie.

 

@Dave nice heads up on TAS2 3D. I rented it so I didn't get a chance to see it in 3D. Might have to buy it.

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I still have the XXX's. Haven't found anything worth replacing them with yet. Working on the signal chain and amps currently. No shakers for me. Probably won't ever go that route. One of the DO sub boxes is mid wall behind the couch but it is still about 5 to 7ft from the head rest on the 2 main listening positions. It is also equalized and run level with the other 3 boxes.

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Dave makes a very good point that the near field response greatly changes things and drastically reduces the low end relative to the top bass octaves.This could be equalized of course but I wonder how many are taking the time to flatten the response back out. I also wonder how many are level matching with the other subs or whether the near field sub ends up very hot. Localization also seems like an obvious issue.

 

 

Even if they did flatten the response I'd imagine they'd be eating up a huge chunk of power to boost the low end with it being down so far compared to the subs farther from the seats.

 

 

When I did the experiment years back, I did indeed boost the snot outta the sub. I had the Bassis back then and it goes all the way to 24dB of boost! :o  I used to make the near field response flat to 10 Hz.

 

Back then I made my own 1/12 octave graph paper and used a 1/12 octave sine tone disc, the RS meter and a C weight correction file and drew the trace by hand. :P

 

Here's a old one I pulled from a file cabinet that I transferred onto a blank TureRTA graph. It shows the naked response and the L/T'd response.

 

282239d1ea32770ca0afd17d4d01e090.png

 

I cooked a few drivers but was able to add that much boost (256 times!!) because the subs were near field and obviously level matched.

 

But, the point is that is was necessary to add that much boost or suffer the difference in FR from the subs up front.

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I still have the XXX's. Haven't found anything worth replacing them with yet. Working on the signal chain and amps currently. No shakers for me. Probably won't ever go that route. One of the DO sub boxes is mid wall behind the couch but it is still about 5 to 7ft from the head rest on the 2 main listening positions. It is also equalized and run level with the other 3 boxes.

Yah with that much displacement I can't imagine you'd ever need to replace them....in any size room. Do you run them hot at all?

 

When I did the experiment years back, I did indeed boost the snot outta the sub. I had the Bassis back then and it goes all the way to 24dB of boost! :o  I used to make the near field response flat to 10 Hz.

 

Back then I made my own 1/12 octave graph paper and used a 1/12 octave sine tone disc, the RS meter and a C weight correction file and drew the trace by hand. :P

 

Here's a old one I pulled from a file cabinet that I transferred onto a blank TureRTA graph. It shows the naked response and the L/T'd response.

 

282239d1ea32770ca0afd17d4d01e090.png

 

I cooked a few drivers but was able to add that much boost (256 times!!) because the subs were near field and obviously level matched.

 

But, the point is that is was necessary to add that much boost or suffer the difference in FR from the subs up front.

That is a SHIT TON of boost! I'll bet you cooked a "few" drivers. :D Even though they were level matched, would the amp be close to clipping on scenes with single digit content? 

 

It's funny how even your hand drawn graphs are detailed. Better than those 1/6th Omnimic readings. :lol:

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Yah with that much displacement I can't imagine you'd ever need to replace them....in any size room. Do you run them hot at all?

 

That is a SHIT TON of boost! I'll bet you cooked a "few" drivers. :D Even though they were level matched, would the amp be close to clipping on scenes with single digit content? 

 

It's funny how even your hand drawn graphs are detailed. Better than those 1/6th Omnimic readings. :lol:

 

Funny, I never thought of it, but you're right. 1/12 octave resolution is higher than 1/6 octave.

 

I had the level down for near field, but yes, that's what sent me on a 10 year search for higher power amps. I sucked the life out of the amps I used back then (Adcom, Alesis Matica, Crown, QSC, American Audio, Marathon).

 

I had one early Chinese driver that had an aluminum cone and the terminal leads were sewn on top of the top spider. When a ULF scene would hit, it moved so radically that the cone bottomed onto the lead wires and there was a flash of lightning. Stupid me, I jumped and wondered what the hell was that? A couple more hits like that before I figured out what was happening and I still think about how amazing it was that the driver and amp kept playing after that.

 

Imagine a flat-to-7 Hz native response with no room gain. :rolleyes::lol:

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That was gonna be my next question: What amps were used and how bad was it? That's hilarious. I woulda crapped myself if I saw a flash of lightning coming from my drivers. I guess those Chinamen didn't expect some crazy American to apply 24db of boost to their drivers. :lol:

 

I remember Adcom amps. Those were some big ole amps. Not cheap either. I'm surprised they could do your subs justice though. No way these lower cost amps are doing 24db of boost. Flat to 7hz? Maybe at 90db haha.

 

Only if I had the displacement and proper power would I do nearfield sealed. If not Pop's monster sub seems just right. Sad thing is even if the SI's were integrated properly I doubt they would've added anything to the experience....though they did look pretty imposing right next to the couch. :)

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Madael I run my subs flat to about 3dB hot depending on the source or what I'm listening to. That's it. How these guys claim to run 10 to 20dB hot and they are at REF +15 on the subs or whatever is beyond me.

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Dave makes a very good point that the near field response greatly changes things and drastically reduces the low end relative to the top bass octaves.This could be equalized of course but I wonder how many are taking the time to flatten the response back out. I also wonder how many are level matching with the other subs or whether the near field sub ends up very hot. Localization also seems like an obvious issue.

 

It can be done right though. With my nearfield, it is not level matched to the front, rather, I run it a good 4-5dB lower than the "main subs" so the response does not suffer. If run level, the response gets boosted from around 40hz through 80-100hz and you no longer have a nice smooth FR to the single digits, instead a peaky mess that basically rolls off at 6dB/oct down to where the nearfield's response is low enough that you get back to your native 3-4m response from your "main subs."  This is no good, obviously. Two ways to combat this is either run the nearfield low enough that it just simply adds to the experience, but doesn't affect the nice FR that you had previously with traditionally placed subs, or Cross the nearfield low, like, 30-40hz low, and use it simply as an air pump to increase your tactile sensation. I have to say, done right, it has really added the sensation I was looking for, whilst not affecting the FR all too much, it certainly is a game of finesse to get it all right though....

 

That was gonna be my next question: What amps were used and how bad was it? That's hilarious. I woulda crapped myself if I saw a flash of lightning coming from my drivers. I guess those Chinamen didn't expect some crazy American to apply 24db of boost to their drivers. :lol:

 

I remember Adcom amps. Those were some big ole amps. Not cheap either. I'm surprised they could do your subs justice though. No way these lower cost amps are doing 24db of boost. Flat to 7hz? Maybe at 90db haha.

 

Only if I had the displacement and proper power would I do nearfield sealed. If not Pop's monster sub seems just right. Sad thing is even if the SI's were integrated properly I doubt they would've added anything to the experience....though they did look pretty imposing right next to the couch. :)

 

You talking about Pop's SI's? Oh they definitely added to the experience. Of course, his little alcove where he had his setup in his open basement basically made it like a 6th order bandpass box....and you were sitting in the back chamber!!!!

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Thanks for chiming in, Brandon.

 

From my experiences setting up systems for other people (read; calibrating flat) over the years, then popping back in to say 'hey' months later and seeing the subs bumped to +10dB hot, I truly believe that most enthusiasts would prefer the "peaky mess" you describe.

 

It cracks me up how the AVS fora are clogged with experts comparing a 0.5dB increase in output with 3% less THD to 'prove' which sub is the mostest bestest and then post a (+/-)10dB FR with the sub at +10dB hot. That's simply comparing inaudible distortion vs output in dBSPL differences at ground plane outdoors to utterly gross, ridiculously audible distortion at the seats at home.

 

Yes, it's a fine dance to get 8 discrete channels of 3 Hz-20k Hz digital audio properly calibrated and integrated with multiple seating positions in a relatively very small venue to a (+/-) 3dB response. I always thought that how to do that would be the crux of the discussions vs " my 'x' sub hits 3dB harder than your 'y' sub at 2M GP".

 

It's cool to blast away with whatever source and clock it for dB drag stats and talk about how it cracked the ceramic in your neighbor's shower stall, really, it is. But, everyone should first be able to brag 3-120 Hz at reference level with (+/-) 3dB response as their reference system before engaging in those grossly distorted exercises.

 

I keep going back to the revelation I felt when seeing Keith Yates' Way Down Deep series in which he included digital spec lab caps vs mic'd spec lab caps using the actual scenes of actual soundtrack that we all were trying to reproduce in our HTs. Of course, they showed no room gain because he measured the mic'd version outdoors, but what a metric! I still think it's the best metric and certainly one that should have been expanded upon in the 11 years since.

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I have nearfield subs now and on a riser. They are not less then 1 meter away from all the seats. I have half the displacement in the back then I do from the front and when I measured them before they had about the sensitivity since I lose 6 dBs from the front wall to my LP. When I get the wall properly sealed up I will post the differences between the two at the same Input levels. I do have more tactile feeling but I added 4 more 18's and also built a riser for all seats. Hard to tell which added the tactile effect.

 

Bosso,

When you graphed the close mic and then moved it away the LT was in place for all? It makes sense if it was.

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Yes, the only thing that changes in the exercise is the mic (which represents the listener) distance from the sub. Here is the same experiment done a few years back, but with the low end normalized instead of the top end.

 

65224d263730bb2875af24119a99c3dd.png

 

I was trying to break down the so-called Pressure Zone or Pressure Vessel Gain bandwidth vs the transition bandwidth and above that, but you can still see the difference in FR.

 

I agree with Josh when he says that the close mic or near field response needs to be EQ'd to match the far field response and this exercise is the evidence. I've repeated the experiment over the years and have placed the subs in lots of different places in the room as well as the mic positions and I always get the same response.

 

The ultra low frequencies are not subject to the inverse square law but the higher frequencies are. That means that your response curve will change with distance, plain and simple.

 

Can you measure from your seat just the front subs playing, then just the rear subs playing, then both, without moving the mic?

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Just graphed 4 scenes from John Wick. We watched this last night in the bedroom and only got the 30-40 Hz stuff with the little ported sub in that system. Today, I watched it in the HT with Raptor System 3.

 

Just a slight difference.  :rolleyes:

 

28d000b6f302f68987437235cb47aa22.png

 

Man, talk about gunshot transients. A whole different movie! Also, check out the frequency spread of the music in the club scenes. Pretty awesome stuff. Liked the movie, loved the sound.

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Dave makes a very good point that the near field response greatly changes things and drastically reduces the low end relative to the top bass octaves.This could be equalized of course but I wonder how many are taking the time to flatten the response back out. I also wonder how many are level matching with the other subs or whether the near field sub ends up very hot. Localization also seems like an obvious issue.

The FR I posted is 4 subs farfield, and 4 subs nearfield, delayed for best FR. Only real prob is at 60Hz, mode related. I love the nearfield augmentation, particularly in the ULF region, but midbass was also improved substantially. The nearfield subs are at same amp level, and I EQ'ed the system as a whole.

 

JSS

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 @Ricci

Hahaha man you made me lol. I'm one of "those guys". Dave gives me shit all the time for it but the *only* reason I run hot is because flat I can't feel anything. Around 10db hot is perfect in my room. If it weren't for the basement I know I would be running flat. Upstairs I'm running the BB flat and it's TOO potent. That thing scares the crap outta me. Suspended floors are amazing.

 

@ Brandon

No I meant the 15" SI's I had. I know 8 SI 18's would make a difference. :P 

 

How you did it makes sense and maybe next time I head down to see Dave I can hear your set-up. I wonder is everyone running their nearfield subs like that though? Also are those 2 HST's capable of ULF on their own? You have an amp just for them correct? They still fall under the same rules as the farfield subs. With only roughly 17 liters of air between them, and your room is roughly 3500cuft right, how can they even do ULF without the help of your other 18's? IOW whatever you're getting for ULF is with ALL subs running so those HST's are only doing so much and are more usefull above 15hz or so than below when placed nearfield. Not to mention you have to boost the ULF considerably and risk clipping the amp. I'm curious without the farfield subs how much they'd do on their own. With enough displacement, like Pop's it woudn't matter, but then what's the point if you don't have enough.

 

 

 

 

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The FR I posted is 4 subs farfield, and 4 subs nearfield, delayed for best FR. Only real prob is at 60Hz, mode related. I love the nearfield augmentation, particularly in the ULF region, but midbass was also improved substantially. The nearfield subs are at same amp level, and I EQ'ed the system as a whole.

 

JSS

 

 

Can you measure far/near/both with mic in same position for all 3 as well?

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 @Ricci

Hahaha man you made me lol. I'm one of "those guys". Dave gives me shit all the time for it but the *only* reason I run hot is because flat I can't feel anything. Around 10db hot is perfect in my room. If it weren't for the basement I know I would be running flat. Upstairs I'm running the BB flat and it's TOO potent. That thing scares the crap outta me. Suspended floors are amazing.

 

@ Brandon

No I meant the 15" SI's I had. I know 8 SI 18's would make a difference. :P 

 

How you did it makes sense and maybe next time I head down to see Dave I can hear your set-up. I wonder is everyone running their nearfield subs like that though? Also are those 2 HST's capable of ULF on their own? You have an amp just for them correct? They still fall under the same rules as the farfield subs. With only roughly 17 liters of air between them, and your room is roughly 3500cuft right, how can they even do ULF without the help of your other 18's? IOW whatever you're getting for ULF is with ALL subs running so those HST's are only doing so much and are more usefull above 15hz or so than below when placed nearfield. Not to mention you have to boost the ULF considerably and risk clipping the amp. I'm curious without the farfield subs how much they'd do on their own. With enough displacement, like Pop's it woudn't matter, but then what's the point if you don't have enough.

 

Yes, exactly. If those with both far and near post 3 traces; 1) far only, 2) near only and 3) Both with the mic not moved from the LP, that will explain everything.

 

Looking at Pop's near field vs far field FRs from my own archives, and, Of course, like most OM graphs, I either transfer the traces to an empty REW graph or stretch the OM graph to the REW graph scale because the OM scale is too squeezed.

 

Also, keep in mind that Pop's near field subs were up against a wall, as was the seating and, consequently his measurement mic, which always offers a >6dB boundary gain boost, and these traces were done after MiniDSP EQ was applied. But you can still see the diff between far and near.

 

df47a5be2a309669d2c5ad6dbeef1d69.png

 

Hahaha, Adam, you get to ride Pop because I think he was running +25-30dB hot.  :D:lol::o:P

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