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Rockford Fosgate T3 19 discussion

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Started reading some of the DSP section of the K20's manual, didn't take long for my eyes to cross.  :wacko:  When you engage the peak limiter, do you notice any latency? 

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Cool graphs Bosso. Yep I've got about 12-15dB of gain by 10Hz. 6-8Hz is the sweet zone. Tons of gain there. I find that bump interesting as it has shown up in numerous room measurements I've seen from different rooms. I already had all the displacement I needed previously and the flatness of the natural room response below 40Hz is awesome. My problems have always been related to the hand off region between the subs and mains and the kick drum area. Believe it or not I ran out of headroom in that area quicker than I'd like. I was having to cut the middle bandwidth of the XXX's by a lot to flatten the response which put a lot of power into them in the 60-100Hz range with music. 43Hz peak is the placement of the seating position. Not willing to do anything there.

 

I agree with the philosophy and the down side of the XXXs.

 

Well, you'll have mid bass like a volcano. That might make it difficult to run hot. Of course, you said at the GTG that you (like myself) prefer a much more balanced presentation than we heard at the GTG and at many demos by other members who seem to prefer the low end to run hot by 15dB or more.

 

Looks like you'll just have to invite us over for a listening session. :ph34r:

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Ricci, is your listening room closed with a door or open to the rest of the house? 

I ask because in my previous room I had that bump at 6-8hz and a fairly sharp roll off below 5hz when the door was open. 

Closed door resulted in no 6-8hz bump and less drop below 5hz... 

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Ricci, is your listening room closed with a door or open to the rest of the house? 

I ask because in my previous room I had that bump at 6-8hz and a fairly sharp roll off below 5hz when the door was open. 

Closed door resulted in no 6-8hz bump and less drop below 5hz... 

 

Open to a hallway, with a tee into another short hall way and an open staircase with no door at the top. I had a rough sketch floating around at some point.

 

 

post-5-0-71555500-1448902041_thumb.png

 

post-5-0-53877300-1448902099_thumb.png

 

 

Started reading some of the DSP section of the K20's manual, didn't take long for my eyes to cross.  :wacko:  When you engage the peak limiter, do you notice any latency? 

 

I don't use limiters. My default preset of settings for the K20's is called "Wide Open". I have used them a bit before during a club type sound reinforcement setting with cabs that couldn't quite handle the full brunt and did not notice any issues. Actually I've never noticed any latency issues. I have on some much cheaper DSP solutions in a mic'd up live sound or recording type of setting. That's the type of setting where latency actually matters.

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Well, you'll have mid bass like a volcano. That might make it difficult to run hot. Of course, you said at the GTG that you (like myself) prefer a much more balanced presentation than we heard at the GTG and at many demos by other members who seem to prefer the low end to run hot by 15dB or more.

 

 

I'll have the same low end headroom as the XXX's but with lower distortion, much better power handling and less thermal compression, and as you say volcano like mid bass. I'll still run things flat though. It's just that I was effectively boosting the XXX's up top, where I'm effectively cutting these 19's over the same bandwidth. These will use probably 1/6th the power for the same output over that bandwidth.

 

I do run my bass close to flat most of the time. Occasionally yes I do have some fun and run the bass hot and crank it. Don't we all? Most listening is with the bass flat though. Listening to the bass system run 12-15dB hot, like it seems to be at most GTG's, compared to run flat, is a gigantic difference as I'm sure we're all aware. I'm also not on a suspended floor and don't have a riser so I also have less tactile sensation than a lot of rooms. The end result is that the couple of guys who have heard it have thought that it sounded lean on the low end. Larry was one of them. It was very brief but he had just heard yours a week earlier. If I remember right he said your system felt like an amusement park ride with intense tactile shake. He thought mine was a bit thin on the low end in comparison, with much less body feel, but that the punch and decay up top were a lot different on mine. Basically that despite having frequency responses that are both basically flat from 5-100Hz the presentation and bass sound is much different. That's just what I recall from a brief conversation. I was curious so I asked him.

 

I'm sort of talking myself into running it +10dB aren't I? :D

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Hehehe, this is so awesome. :D

 

This is why I've got twelve JBL 2226's running in tandem with just as many subs. Can't blame the speakers for any lack of midbass.

 

Bosso - we need to get you hooked up into the world of Vibsensor. Frequency response is not everything.

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I'll have the same low end headroom as the XXX's but with lower distortion, much better power handling and less thermal compression, and as you say volcano like mid bass. I'll still run things flat though. It's just that I was effectively boosting the XXX's up top, where I'm effectively cutting these 19's over the same bandwidth. These will use probably 1/6th the power for the same output over that bandwidth.

 

I do run my bass close to flat most of the time. Occasionally yes I do have some fun and run the bass hot and crank it. Don't we all? Most listening is with the bass flat though. Listening to the bass system run 12-15dB hot, like it seems to be at most GTG's, compared to run flat, is a gigantic difference as I'm sure we're all aware. I'm also not on a suspended floor and don't have a riser so I also have less tactile sensation than a lot of rooms. The end result is that the couple of guys who have heard it have thought that it sounded lean on the low end. Larry was one of them. It was very brief but he had just heard yours a week earlier. If I remember right he said your system felt like an amusement park ride with intense tactile shake. He thought mine was a bit thin on the low end in comparison, with much less body feel, but that the punch and decay up top were a lot different on mine. Basically that despite having frequency responses that are both basically flat from 5-100Hz the presentation and bass sound is much different. That's just what I recall from a brief conversation. I was curious so I asked him.

 

I'm sort of talking myself into running it +10dB aren't I? :D

 

I can personally attest that Bosso's floor is a trampoline <15hz.  Not only is his entire theater on a suspended floor, the rear seating is also on a riser.

 

When the dual HST-15s were shaking the floor with more tactile sensation than my dual Ghorns pumping out 134db at 15hz, I was seriously jealous and angry at the same time!

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Hehehe, this is so awesome. :D

 

This is why I've got twelve JBL 2226's running in tandem with just as many subs. Can't blame the speakers for any lack of midbass.

 

Bosso - we need to get you hooked up into the world of Vibsensor. Frequency response is not everything.

 

Agree 100%.

 

By far the most puzzling situation for me was a guy on AVS who lives about 20 min from me in Minneapolis.  He has a PSA Triax and wanted me to come over and measure his subs because he felt the low end was non-existent.

 

It turns out, his response was crazy flat to 12-13hz, but below 25hz there was nothing felt nor heard.  His room was really small too, probably only ~12x15.

 

triax_zpsxv2pjqnb.jpg

 

 

 

No vibration of the floor, walls, couch...nothing below 25hz.  Really bizarre. 

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I had a similar experience in my room a month ago. Was doing some EQ revisions with my sub system and did A LOT of tinkering. So I ended up with a totally flat response to below 15hz with no EQ filters at all. I was astounded. But... even though I had a perfect response at the seat, something was missing. Maybe it wasn't loud enough but something was off, way off. Well...something was off. Almost all my subs. Had forgot to re-raise the levels for all but two of my subs so it was just the two nearfields going alone. It was still loud actually (not surprised with four 18's) but even with a totally flat to below 15hz response the experience was just "meh" at best. Anyway, found out a couple days later and fixed it. Now back in business!

 

But anyway... frequency response is super important, obviously but it's not everything. Working with the Vibsensor app and taking measurements of my own system was a huge eye opener to me. I found that this is the missing link in the puzzle to situations like you experience with your friend and that MANY of us deal with from room to room, system to system. If you're not using Vibsensor with things like REW, Omnimic, SpecLab... then you're not seeing the whole picture. It's time to get with the times and evolve, folks. Measuring just the FR alone is like living in the dark ages.

 

Wait... what the f*** does this have to do with this awesome driver? :D:P

 

My bad. Carry on. :)

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Regarding frequency response, I'm a musician first. As a bass player, I imagine a bass where each fret of each of the 4 strings has a different loudness. Into the trash can it would go. It's imperative that the dynamics come from the player and the overall level comes from the mixer. The frequency response of the instrument must be flat, meaning no hot spots and no dead spots.

 

It's also equally important (to accuracy) that the in-room response be flat as well. In those respects, FR is everything.

 

Regarding the tactile feel, you can attribute much of my system;s shake to the dual-opposed, up/down fining stacks in each corner. I can engage the 18 Hz HPF of the SEQSS and still feel the tactile response at the seats from 20 Hz through cross. That has little to do with being on a wood framed floor system, and that's a huge disparity in playback response.

 

jusShg4.png

 

Brandon's rig is set up similar to mine in the front stage and, IMO, his system has plenty of tactile effect without the in-your-spine HST-18s. IMO, he not only doesn't need the nearfield 18s, they were actually a bit annoying to me, especially during music only playback, where they crossed the line between musical tones and completely non-musical  massage tones.

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I'd be interested in your real-life reaction to using Vibsensor with your frequency response graphs.

 

Great. Now repeat that on somebody else's system similar to yours like Adam's.

 

Paul, get a video of your dad's mind being blown and his world turned upside down.

 

Seriously. Vibsensor measurements changed everything. Measuring frequency response is only a part of the experience, what the mic hears. Vibsensor is the other half, what we feel.

 

Try it out. It's free.

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Regarding frequency response, I'm a musician first. As a bass player, I imagine a bass where each fret of each of the 4 strings has a different loudness. Into the trash can it would go. It's imperative that the dynamics come from the player and the overall level comes from the mixer. The frequency response of the instrument must be flat, meaning no hot spots and no dead spots.

 

It's also equally important (to accuracy) that the in-room response be flat as well. In those respects, FR is everything.

 

Regarding the tactile feel, you can attribute much of my system;s shake to the dual-opposed, up/down fining stacks in each corner. I can engage the 18 Hz HPF of the SEQSS and still feel the tactile response at the seats from 20 Hz through cross. That has little to do with being on a wood framed floor system, and that's a huge disparity in playback response.

 

jusShg4.png

 

Brandon's rig is set up similar to mine in the front stage and, IMO, his system has plenty of tactile effect without the in-your-spine HST-18s. IMO, he not only doesn't need the nearfield 18s, they were actually a bit annoying to me, especially during music only playback, where they crossed the line between musical tones and completely non-musical  massage tones.

 

Any evidence/data to support this?  It seems you're suggesting the alignment of the sealed subs has a direct effect on the resonating surfaces in the room (in this case the floor), and additionally that it's also not related to SPL?

 

Like everyone else I've sold subs that I've built, but I've also been shocked to find that my own sub was completely unrecognizable in a friends HT room which is on the 2nd floor of his house.  Not only was he using less than half the power I was, his room was 3-4x larger and basically open to every other room on his main floor.  He didn't even have two full walls on his HT.  

 

The difference in tactile feel <20hz was planets apart. 

 

 

 

I'd be interested in your real-life reaction to using Vibsensor with your frequency response graphs.

 

Great. Now repeat that on somebody else's system similar to yours like Adam's.

 

Paul, get a video of your dad's mind being blown and his world turned upside down.

 

Seriously. Vibsensor measurements changed everything. Measuring frequency response is only a part of the experience, what the mic hears. Vibsensor is the other half, what we feel.

 

Try it out. It's free.

 

My approach is always to try it and just find out, hence me selling my beloved tapped horns to try sealed again.  I'd really like to see the difference of a vibsensor at 10hz and lower between Bosso and Brandon's systems.  Brandon's system, while epic in every respect, in my experience didn't have the same dizzying floor rumble that Bosso's room has below 10hz.  After all, why would anyone expect a concrete slab to resonate like a suspended wooden floor?!?

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Isn't your body's sense of feeling the ultimate gauge of "tactile feel"?  Aren't the differences in tactile feel for similar systems mainly the resonances of different things that come into contact with our bodies -couches, floors, risers?  Other than that the only major factor I could think of is how much energy is lost from the construction of the room.  We can change the frequency response of a system but when it comes to tactile feel, what would be the adjustment?    Even to accurately measure a thing like that for the tactile feel of a system would need to be isolated from contact with surrounding surfaces or it would skew the results? 

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Tactile Feel is way too broad a term.  It incorporates furniture/floor resonances, body cavity resonances, clothing movement (very little movement of clothing is all it takes for 'pant flapping' to be felt).

 

While the VibSensor is a great first step, simply changing the axis of measurement can yield very different results, and different results on a different part of the floor or piece of furniture.

 

That being said, I think between accelerometer readings on furniture, directional soundfield readings a'la Kvalsvoll, and conventional FR/SPL, a very good picture of what a room can sound and feel like could be had.  

 

JSS

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Yes, the mystery of the untamed audio beast... the subwoofer bandwidth. :lol:

 

Everyone wants the simple answer so that they can claim to have solved the mystery without the expense and the leg work.

 

No, it isn't the sealed system.

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Cool graphs Bosso. Yep I've got about 12-15dB of gain by 10Hz. 6-8Hz is the sweet zone. Tons of gain there. I find that bump interesting as it has shown up in numerous room measurements I've seen from different rooms. I already had all the displacement I needed previously and the flatness of the natural room response below 40Hz is awesome. My problems have always been related to the hand off region between the subs and mains and the kick drum area. Believe it or not I ran out of headroom in that area quicker than I'd like. I was having to cut the middle bandwidth of the XXX's by a lot to flatten the response which put a lot of power into them in the 60-100Hz range with music. 43Hz peak is the placement of the seating position. Not willing to do anything there.

 

You look like a great candidate for independent DSP on each sub.  Your room and sub placements are very asymmetric (as far as bass is concerned).  Do you at least use independent delays on those guys?  Delay optimization alone could improve your 60-100 Hz response quite a bit.

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Tactile Feel is way too broad a term.  It incorporates furniture/floor resonances, body cavity resonances, clothing movement (very little movement of clothing is all it takes for 'pant flapping' to be felt).

 

While the VibSensor is a great first step, simply changing the axis of measurement can yield very different results, and different results on a different part of the floor or piece of furniture.

 

That being said, I think between accelerometer readings on furniture, directional soundfield readings a'la Kvalsvoll, and conventional FR/SPL, a very good picture of what a room can sound and feel like could be had.

 

I completely concur.  Tactile sensation of sound is very complicated.  Whereas we only hear with one pair of ears, a multitude of different sensory organs contribute to the vibrotactile sense.  Then there's the multitude of ways that the energy can reach those senses.  While talking about the tactile, we also have to talk about sound above the subwoofer region, which can contribute quite a bit of sensation in the chest.  I know I've felt tones upwards of 200 Hz in my chest, and I'm willing to bet that many of the ladies feel sound quite a bit higher due to their smaller diaphragms on average.

 

I'm still pretty skeptical about the sound intensity playing a role.  When we talk about FR, we rarely specify what kind of smoothing is being used in the comparisons.  So-called "transient response" may have a lot to do with it, in addition to vibrotactile considerations, and transient response may be made to disappear from the FR if too much smoothing is used.  I believe 1/24th octave is the absolute minimum for bass.  For < 120 Hz, I usually prefer to review my measurements responses un-smoothed and a very long time window.

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Vibsensor is a useful tool for seeing what is going on on a particular surface under ~40Hz. I don't see this as having anything to do with transient response nor music playback. I find that that effect, since adding a NF sub, accentuates feelings of dread/tension during certain scenes and that running it too hot makes it a bit too much of a rollercoaster. If I sense the NF during music playback then that is just wrong for my preference.

 

My preference sounds closer to bosso with respect to FR BTW, I run it with a small (~3dB) lift from 120Hz down to 40Hz (roughly) and flat from there. The NF response is broadly flat from 15-45Hz and rolls off steeply either side using 2nd order NT filters, this means the NF is really completely gone by 60-70Hz (and the filter is setup so that combines nicely with the main sub to avoid any artefacts as we move firmly into the audible range).

 

Personally I think it was a great vfm upgrade, not essential but nice to have for sure.

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transient response may be made to disappear from the FR if too much smoothing is used. I believe 1/24th octave is the absolute minimum for bass. For < 120 Hz, I usually prefer to review my measurements responses un-smoothed and a very long time window.

i don't follow you here, what is the connection between steady state fr with effectively no gate (or smoothing) and transient response?

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post-5-0-20566600-1448746428_thumb.jpg

You look like a great candidate for independent DSP on each sub.  Your room and sub placements are very asymmetric (as far as bass is concerned).  Do you at least use independent delays on those guys?  Delay optimization alone could improve your 60-100 Hz response quite a bit.

 

Not so much...3 of the SW cabs are very symmetric with the main 2 listening positions. Delay is not needed there. The 4th one is close to near-field for seat 2 and 3. If any of them would benefit from delay it would be that one. However I tried it before with my old system and it did not improve the sound subjectively or the measurements much either. I initially thought the same thing and was a bit surprised. That was with many hours of tweaking and at the end of the day I decided it just wasn't worth the time and extra setup complexity in the DSP. Not surprising since it is only responsible for 1/4 of the total energy. I thought it would time align the initial pressure wave and make sharp transients punchier sounding but it just didn't. Perhaps I'll revisit if I get froggy.

 

As far as individual DSP other than time delay or perhaps gain, I'm just not a fan of that unless the subwoofers are different. While you may correct the individual responses at a single point in space it jacks up the total energy being emitted into the space everywhere else. So much of the bass is reflected it seems to feel different and sound different in the room despite what may measure very flat at one spot. You also start driving certain subs harder than others at different frequency ranges which diminishes your total headroom.  Again I tried this before and just didn't like it in my particular system. In ther systems it may be called for or other people may find it worthwhile for their setup.

 

60-100Hz is not a problem area...Did you see the raw response I posted that you tied into your post? :huh:

No smoothing, no EQ and about +/-2dB from 50-100Hz.

There is a LPF from my Onkyo in line which is rolling off the top end as well. 43Hz spike is related to seating position, dead center of the room. Can't do much there other than move the seating placement, which I can't by any more than 2ft fore or aft. It doesn't change that much. Real problem area is 100-300Hz as with most spaces. I need treatments badly...That's probably my next move.

 

 

The room layouts I posted are not perfectly to scale BTW.

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Cool graphs Bosso. Yep I've got about 12-15dB of gain by 10Hz. 6-8Hz is the sweet zone. Tons of gain there. I find that bump interesting as it has shown up in numerous room measurements I've seen from different rooms. I already had all the displacement I needed previously and the flatness of the natural room response below 40Hz is awesome. My problems have always been related to the hand off region between the subs and mains and the kick drum area. Believe it or not I ran out of headroom in that area quicker than I'd like. I was having to cut the middle bandwidth of the XXX's by a lot to flatten the response which put a lot of power into them in the 60-100Hz range with music. 43Hz peak is the placement of the seating position. Not willing to do anything there.

 

The hump you are seeing at 6-8hz is called Hemholtz Resonator Response. I to have this hump in my living room that has a 44"x4ft deep entrance opening going to the kitchen. When I first got my UMIK I thought there was something wrong with it since this hump showed up in every graph I took regardless of position of subs or settings. Mine is more pronounced and centered at 10hz.

 

I emailed the guy in charge of calibrating the UMIKS at Cross spectrum. HE had me send him some graphs I took with REW. He then asked me If I could take one of the subs to a bedroom that could be sealed off by a door. So I lugged one of my Cap S2's into the room and set up my equipment ( that was alot of fun, haha). Ran some sweeps with the door shut and it was flat to 5hz. Opened the door and the hump came back at 7-8hz. He told me that this is classic Hemholtz resonator response. Basically our single opening to another room acts as a very large port in the simplest explanation he said. Where the hump is located in the frequency band and how big will be determined by the size of your opening and to some degree the depth of the hallway or length going in to the next room.

 

I dont have any EQ setup yet. Do have a balanced minidsp that I havent hooked up yet. When I do I dont even know if I would even tame my peak there, I look at it as just free power in the area. I know 10hz material really hammers in my room so I'll take it.

 

Here the only graph I have on my phone but gives you the idea of my room and my hemholtz peak.

 

post-2682-0-24834700-1449069834_thumb.jpg

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Regarding frequency response, I'm a musician first. As a bass player, I imagine a bass where each fret of each of the 4 strings has a different loudness. Into the trash can it would go. It's imperative that the dynamics come from the player and the overall level comes from the mixer. The frequency response of the instrument must be flat, meaning no hot spots and no dead spots.

 

It's also equally important (to accuracy) that the in-room response be flat as well. In those respects, FR is everything.

 

Regarding the tactile feel, you can attribute much of my system;s shake to the dual-opposed, up/down fining stacks in each corner. I can engage the 18 Hz HPF of the SEQSS and still feel the tactile response at the seats from 20 Hz through cross. That has little to do with being on a wood framed floor system, and that's a huge disparity in playback response.

 

jusShg4.png

 

Brandon's rig is set up similar to mine in the front stage and, IMO, his system has plenty of tactile effect without the in-your-spine HST-18s. IMO, he not only doesn't need the nearfield 18s, they were actually a bit annoying to me, especially during music only playback, where they crossed the line between musical tones and completely non-musical  massage tones.

 

Yea but they are just so FUN! Haha. I agree they aren't necessary, and their largest benefit is when I use them latenight to get a good tactile feel without having the front subs on, as they travel up that wall to the master bedroom and wake the sleeping princess....

 

I'd be interested in your real-life reaction to using Vibsensor with your frequency response graphs.

 

Great. Now repeat that on somebody else's system similar to yours like Adam's.

 

Paul, get a video of your dad's mind being blown and his world turned upside down.

 

Seriously. Vibsensor measurements changed everything. Measuring frequency response is only a part of the experience, what the mic hears. Vibsensor is the other half, what we feel.

 

Try it out. It's free.

 

Did you end up documenting what the vibsensor was getting at the g2g? 

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Not really. I saved one graph from EoT but with all the things going on that day I did not properly document your system with the app.

 

Though I will say... the single reading I took was heavily clipped which isn't good data but it simply means "holy shit!". So... you're doing pretty good. :)

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