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post #2971 of 3237 Old 03-14-2015, 11:25 PM
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Post current setup

Here's where I stand currently (at least until I can match my new sub ). I went back and got more accurate measurements of my space, and this seems to be pretty close.
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Sammy UN78HU9000FXZA || Onkyo TX-NR616 (7.1; sub= HSU VTF-3 Mk 5, fronts= Klipsch R-3650-WIIs, center= RP-160M, surrounds= R-2650-Cs, rear surrounds= Polk RC80is) || Panny DMP-BD60 || Sony PS3 || AppleTV

Last edited by galonzo; 03-15-2015 at 12:15 AM. Reason: wrong sub selected
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post #2972 of 3237 Old 03-15-2015, 07:54 AM - Thread Starter
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Quote:
Originally Posted by galonzo View Post
Here's where I stand currently (at least until I can match my new sub ). I went back and got more accurate measurements of my space, and this seems to be pretty close.
^^ Will include you in the next update.

Is nearfield placement an option? Massive space you got there...that would certainly help with tactile feel and help offset the large space.
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post #2973 of 3237 Old 03-15-2015, 08:55 AM - Thread Starter
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Quote:
Originally Posted by dominguez1 View Post
This is a very interesting observation...and one that has me scratching my head a bit as it doesn't seem intuitive to at least how I understand it (and I'm no expert, mind you).

Sound Intensity is sound energy per unit volume. It is what we 'feel' from a sound source. The equation for Sound Intensity is:

I = p * v

where

I (Sound Intensity Level) = pressure (SPL) * particle velocity (PVL)

All are measured logarithmically in db.

When in the nearfield, PVL is the dominant quantity; meaning that any change in Intensity (tactile feel) in the nearfield is related to fluctuations in PVL as opposed to SPL. This was demonstrated in my test here. To summarize, I measured the tactile feeling of a sub 13ft away at a constant SPL, and measured a sub 3ft away at the same SPL, and the sub 3ft away quantitatively had far more tactile feeling. Two subs, different distances, exact same SPL, but felt entirely different. The reason? Give the equation above, it could only mean higher levels of PVL and thus more Sound Intensity (since SPL is kept constant).

I often refer to PVL as the cause of tactile feeling, when really it is Sound Intensity, but in the nearfield, PVL is the driver for the increased Intensity.

Back to your observations...I would have thought that tactile feeling would be directly related to the frequency response; a null at a certain frequency would reduce SPL and thus Sound Intensity, just as a peak would increase SPL and Sound Intensity as well.

You observed quite the opposite; essentially that the tactile feeling was NOT linked to the FR but more to whether or not the sound waves were in phase. Time alignment was the driver for great tactile feel, not FR (or spl levels).

I don't quite understand the science behind that...not saying its wrong, just don't understand. Particle Velocity and Pressure have can be in or out of phase with respect to each other, but wasn't sure if particle velocity can be out of phase by itself as combines with different waves (in your case another sub).

Perhaps this is what's happening:

Scenario A:
Let's say that the nearfield sub produces 100db at 15hz by itself. Let's also assume that the farfield sub also produces 100db at 15hz by itself. But, when you turn both on, the summed output is only 90db (i've experienced this before); I would assume this means that they are not in phase. If they were perfectly in phase, you would get 106db.

Scenario B:
Same two subs, but now they are in phase. So the nearfield sub produces 84db at 15hz, as does the farfield sub. Since they are perfectly in phase, the summed SPL level is 90db.

Here's the question: Which scenario will have more tactile feel?

There is more Sound Power being produced in Scenario A, even though it nets to the same level SPL as Scenario B. Does that mean that there's more tactile feel? My qualitative observations in my room say yes, but I don't understand the science behind it.


Going to have to call for backup...

@neutro or others, please weigh in?
Quote:
Originally Posted by Okv View Post
I would think a would have a larger velocity potential, out-of-phase sources creates velocity.
To be sure, you would need to test it.

Listen and experience, then measure, both velocity and pressure, with this information you can then try to see if there is a correlation between measurements and listening experience.

I have tested many different configurations, and generally the ones with flat (smooth) fr and phase, clean and nice step response and at the same time a decent velocity potential sounds best.

A double bass array is one example of a setup that gives a predictable behavior for both pressure and velocity.
So I decided to test my hypothesis...

I'm testing a single frequency (27hz) using a sine wave. 27hz is one of the resonant frequencies of my room.

I placed my android phone with the Vibration Meter app at my main LP. Looped the 27hz sine wave and recorded the results. I also changed the phase of my pair of FTW21s and left the phase of my FV15HPs alone.


The Vibration Meter recorded a mean of .6 on the phone.
Recorded Max SPL was 120.4 db
Phase was at ~125 degrees.


In this video, I only changed the phase (kept the main volume the same). As a result of changing the phase:

Vibration Meter recorded a mean of .5 on the phone.
Recorded Max SPL was 104.1 db
Phase was at 0 degrees

That's a 16db swing just by changing the phase!

You can see that there was a very slight difference in tactile feel as the mean dropped by .1. I think for all intensive purposes we can say they are pretty much equal in tactile feeling. So even after a 16db swing in SPL, the tactile feeling is pretty much the same.


So I decided to match the SPL of the first test when the subs were in phase. In the first test, the subs produced 120.4 db. I turned up the main volume by 16db and reran the test with the subs being out of phase.

Vibration Meter recorded a mean of 1.4
Recorded Max SPL was 120.8 db
Phase was at 0 degrees

To summarize, I had two different scenarios producing ~120db, but one had double/almost triple the tactile impact. Same SPL, same distances, far different tactile feedback.

So not only does distance have an impact on tactile feedback (nearfield vs farfield), but phase also plays a big part of tactile feedback; specifically, given a constant SPL, out of phase conditions will produce more PVL, causing more Sound Intensity and thus tactile feedback.

If you think about it, it is intuitive. Think about it from a Sound Power standpoint...in the first test the subs aren't working that hard, but in the third test, they are working a lot harder to produce the same SPL. As a result, even though SPL is the same, there is more Sound Power in the third scenario, thus producing more Sound Intensity and tactile feeling.

This is just another example of how SPL (and thus frequency response) only tells a part of the story...and for this region of frequencies (LF/ULF), one could argue that this is the more important quantity to focus on...yet, most often don't because they don't know about or have heard of PVL or Sound Intensity, or don't have the tools to properly dial it in.
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post #2974 of 3237 Old 03-15-2015, 11:54 AM
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Post Update

Quote:
Originally Posted by dominguez1 View Post
^^ Will include you in the next update.

Is nearfield placement an option? Massive space you got there...that would certainly help with tactile feel and help offset the large space.
Thanks; as much as I'd love to place the sub in the corner behind the sectional (it's actually curved instead of squared off), it's really stuck where it is for now (away from tiny hands that could otherwise get to my sub gain ).

I did one final go through of my calculations, which earned me another 1/2 star in the 16 and 20hz categories; I decided to not include the refrigerator niche, since it's mostly filled with the refrigerator, a microwave on top of it, and a ~20'x1.5'x1' bulkhead that runs along that wall.

So, not including the adjacent sitting area in the bottom-left (not a large enough opening to include), it would be the 30.75'x27.5' area minus the 16.375'x4' bump-in at the bottom (which, by the way, is also a double-wall along the bottom; so an additional 9" ledge around the entire bottom of the floorplan that I didn't include). The ceilings are 8'7".

Again, the listening area is really only that ~18'x11' area (to the black square, which is a pillar holding up a beam that runs through the entire length; which, to my surprise, my wife suggested we wall off after I played her some content with the new sub! Hmmmmmm, doing that and adding the second sub puts me in Reference status!.
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Sammy UN78HU9000FXZA || Onkyo TX-NR616 (7.1; sub= HSU VTF-3 Mk 5, fronts= Klipsch R-3650-WIIs, center= RP-160M, surrounds= R-2650-Cs, rear surrounds= Polk RC80is) || Panny DMP-BD60 || Sony PS3 || AppleTV
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post #2975 of 3237 Old 03-15-2015, 03:00 PM
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Quote:
Originally Posted by dominguez1 View Post
...
So not only does distance have an impact on tactile feedback (nearfield vs farfield), but phase also plays a big part of tactile feedback; specifically, given a constant SPL, out of phase conditions will produce more PVL, causing more Sound Intensity and thus tactile feedback.
..
Exactly.
In a developed free-field soundfield, the relationship between pressure and velocity potential is given, but once you move into a room with walls and boundaries, things start to change quite dramatically, and if you now add multiple sound sources as well, this will also affect the soundfield properties.

In a room, with a standing wave, you will have a null for pressure in the middle of the room, while velocity will be much higher than the free field condition, this happens at the 1/2-wavelength freq.
At 1/1 wavelength you will get pressure maxima in the middle, with no velocity.

So, in a room, it is possible to have the same frequency response, but very different velocity potential, for two different set-ups.

My audio blog at kvalsvoll.blogspot.com - from simple set-up guides and tips to investigations on audio related issues.
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post #2976 of 3237 Old 03-15-2015, 07:33 PM - Thread Starter
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This has got me thinking...this might prove all those crazy ULF setups...well, sane!!!

Why? Based on the above tests, an ideal situation might be to focus the typically audible range (20hz and up) on a flat frequency response so that it 'sounds' like it should. Phase is secondary.

However, once below 20hz, tweak the in-room response so that below 20hz is out of phase and FR is secondary. Below 20hz is typically inaudible, and is more about tactile feel that sound quality. If you were able to be out of phase below 20hz, you would generate more tactile feel as you attempt to get a flat FR below 20hz (as compared to if you were in phase, and your subs weren't working as hard).
@MKtheater , @notnyt , @JapanDave , @Scott Simonian , @BassThatHz , @Fatshaft , @N8DOGG (and other ULF crazy setups), have enough headroom to achieve a flat FR or house curve below 20hz even out of phase. The result would be incredible levels of PVL and sound intensity in the room.

In fact, I would wager that for these top ULF systems above, the reason why their tactile experience has gone up as they've continued to upgrade their system, is a result of them being able to produce more Sound Power and overcome any out of phase conditions that their in-room FR presented. They could have been out of phase in their prior setups, but now have more displacement and watts to power through the out of phase scenarios, creating more PVL, Sound Intensity, and thus tactile feel.

As with my example above, just by turning the phase dial so that the subs were out of phase, I was able to reduce SPL by 16db! To get back to that level, I turned the MV up by 16db, or roughly used 5X the power to get to the same SPL level as if they were in phase. With these monster setups, they can not only do that, but run a huge house curve to boot!

This could also solve the mystery of one room having an identical FR and sub placement as another room, but FAR different tactile experiences.

It could also be the reason why folks perceive some subs as more 'tactile' or have more 'punch'...could be that these subs are a little more out of phase in those frequency ranges, and create more PVL and sound intensity once calibrated flat (e.g. Audyssey) to the other frequencies...

Oh, and as an FYI, in my 27hz test above, I run my subs in the out of phase scenario...no wonder why it's so tactile in my main LP...

Last edited by dominguez1; 03-15-2015 at 07:41 PM.
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post #2977 of 3237 Old 03-15-2015, 07:42 PM
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post #2978 of 3237 Old 03-15-2015, 07:49 PM - Thread Starter
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Quote:
Originally Posted by notnyt View Post
Ported enclosures give you some phase shift naturally.
Great point!

This might be the reason as well why my ported FV15HPs were more tactile than my sealed FTW21s in the same position at the same SPL! I had always thought that the reason was because both the port and the driver were producing PVL in the FV, as compared to the sealed with just the driver.

It seems reasonable to think that the additional tactile feel around port tune was a result of shifting of phase, producing additional PVL, Sound Intensity, and thus tactile feel...
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post #2979 of 3237 Old 03-16-2015, 12:15 AM
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Very interesting stuff! Heres another thing you may find interesting. Comparing my last three rooms (all that I've measured since getting the Omnimic), I've always had a frequency point that response below remains unchanged no matter where the subs are place or phased. Above this point changing phase/time alignment has the obvious affect, while below nothing changes. We can use the term transfer function, room gain or cabin gain, but it doesn't always coincide with those freqs. Room gain starts higher.

For example in my present room That freq is about 23hz. This is no eq of any type.



If thats the case in your room Dom, your 16db phase null may not be effecting those freqs that are exciting your vibrometer. Harmonics can have an effect. I'd like to see your FR from 5-100hz, all subs only, with just phasing changed to see if you or anyone else here has a similar experience.
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post #2980 of 3237 Old 03-16-2015, 07:44 AM
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I have seen this same thing in my room. Below a certain level, no adjustment have an effect for the most part. This could be the limit of the sub, gear, combo of room and system, ect.
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post #2981 of 3237 Old 03-16-2015, 02:36 PM - Thread Starter
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Quote:
Originally Posted by coolrda View Post
Very interesting stuff! Heres another thing you may find interesting. Comparing my last three rooms (all that I've measured since getting the Omnimic), I've always had a frequency point that response below remains unchanged no matter where the subs are place or phased. Above this point changing phase/time alignment has the obvious affect, while below nothing changes. We can use the term transfer function, room gain or cabin gain, but it doesn't always coincide with those freqs. Room gain starts higher.

For example in my present room That freq is about 23hz. This is no eq of any type.



If thats the case in your room Dom, your 16db phase null may not be effecting those freqs that are exciting your vibrometer. Harmonics can have an effect. I'd like to see your FR from 5-100hz, all subs only, with just phasing changed to see if you or anyone else here has a similar experience.
Actually, I do experience the same thing. It's interesting that my freq is also around 23hz if I had to guess.

When I performed this test originally, I used it with a 15hz sine wave. No matter how I changed the phase, the biggest discrepancy that I was able to create was just 1db. At this frequency in my room, phase wasn't that big of a factor.

I then switched to 27hz, as I knew that there would be a big difference there.

Is phase sensitivity (the change of SPL with relation to phase) related to the length of the wave? And that the longer wavelengths need bigger rooms for it to be sensitive for phase? It would have to be some fraction of the wavelength as 27hz is ~42ft. My room's longest dimension is 18ft, so perhaps a 1/3rd of a wavelength? Just guessing here...
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post #2982 of 3237 Old 03-16-2015, 02:54 PM
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You've got to power through it! I did just commission 2 more G-horns to be built and maybe some "otterhorns" lol Just haven't decided yet. I've got a wood working friend that needs a few projects for his class, the guys wanted to build some subs and thats what they are building. It will take a few months at least but it's not like Im in a hurry.

Blasting brown notes for 10 years and counting!

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post #2983 of 3237 Old 03-16-2015, 03:14 PM
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Quote:
Originally Posted by dominguez1 View Post
Actually, I do experience the same thing. It's interesting that my freq is also around 23hz if I had to guess.

When I performed this test originally, I used it with a 15hz sine wave. No matter how I changed the phase, the biggest discrepancy that I was able to create was just 1db. At this frequency in my room, phase wasn't that big of a factor.

I then switched to 27hz, as I knew that there would be a big difference there.

Is phase sensitivity (the change of SPL with relation to phase) related to the length of the wave? And that the longer wavelengths need bigger rooms for it to be sensitive for phase? It would have to be some fraction of the wavelength as 27hz is ~42ft. My room's longest dimension is 18ft, so perhaps a 1/3rd of a wavelength? Just guessing here...
I believe it's a 1/4 wavelength. My long dimension is 15'4". So it looks like as far as ULF's are concerned phase isn't part of the equation, at least in rooms our size. The specific scene I used in my tests above was first minutes of the new Transformer flic when the alien hits the button to detonate the seeed pods. I'll play with the alignment some more as I actually prefer the smoother response with no TA.
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post #2984 of 3237 Old 03-16-2015, 06:13 PM - Thread Starter
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Quote:
Originally Posted by N8DOGG View Post
You've got to power through it! I did just commission 2 more G-horns to be built and maybe some "otterhorns" lol Just haven't decided yet. I've got a wood working friend that needs a few projects for his class, the guys wanted to build some subs and thats what they are building. It will take a few months at least but it's not like Im in a hurry.
You sir have a sickness...wouldn't it be easier to just take a laxative as opposed to the ulf induced brown note?

Very cool, can't wait to see where you put those things!
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post #2985 of 3237 Old 03-16-2015, 06:46 PM - Thread Starter
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Quote:
Originally Posted by coolrda View Post
I believe it's a 1/4 wavelength. My long dimension is 15'4". So it looks like as far as ULF's are concerned phase isn't part of the equation, at least in rooms our size. The specific scene I used in my tests above was first minutes of the new Transformer flic when the alien hits the button to detonate the seeed pods. I'll play with the alignment some more as I actually prefer the smoother response with no TA.
If it's 1/4 wavelength, this would be consistent with the 'nearfield' definition, where if within this range, pressure and particle velocity are not in phase, and particle velocity is the dominant quantity.

Also, I wouldn't say phase isn't part of the equation for ULF...I'd say phase sensitivity is not part of the equation, but certainly phase is part of the equation (albeit out of phase); meaning that within 1/4 wavelength, you are not in phase by default...and trying to time align isn't very effective in the nearfield. That's probably another reason why small spaces are more tactile than large ones...nearfield characteristics are in play, and PVL dominates.

Think of car audio; depending on the size of the cabin, it could put you in the nearfield as early as 80hz (14ft * 25% = 3.5ft). If you are out of phase, and PVL dominates this early in the frequency range, it should be very tactile...which is what folks experience.

Seems to make sense, but would love a scientific eye to weigh in on some of my banter...
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post #2986 of 3237 Old 03-16-2015, 10:40 PM
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I'm wrong on the 1/4 wave. The correct answer is 1/2 or less then half a wavelength. Heres a post explaining it by LTD02 on one of my builds from three years back.



"My rooms dimensions are 18ft x 19ft x 8ft."

"I measured room gain by comparing the Winisd graph against actual in room via the OmniMic and RG starts at +1db@20hz and increases at 10db per octave. It's +11db@10hz and +21db@5hz. Room gain is more than I expected, but I wish it started an octave higher."

pressure vessel gain kicks in when the long dimension of the room is less than 1/2 the wavelength at the critical frequency.

long dimension of the room = (H^2 + W^2 + D^2)^0.5 = (8^2 + 19^2 + 18^2)^0.5 = (64+361+324)^0.5 = 749^0.5 = 27.37 ft.

27.37 is the half wavelength, for the full wavelength multiply by 2 = 54.74 ft.

1130(ft./s) / 54.74 ft. = 20.64 (1/s) = 20.64 hz

the theoretical gain is 12db per octave, but that is if you are losing nothing to wall flexing, etc.

so your room is performing pretty much exactly according to theory.


Using a frequency/wavelength calculator my PVG with a long dimension of 15'4"X11'x9' starts around 22hz, I think which shows on the graph. This is where room gain begins and where phasing's effect ends. I have about the same PVG as room 1(19x18x8) in my current room, room 3{15'4"x11'x9'). I believe room 2 measured the same as well. So while TA/phase/distance can have a drastic effect above PVG it has none below. An average rooms PVG start point is around where ULF starts as well. I've seen this for years looking at the graphs but just never thought of the correlation of ULF and Phase. I think this is why Bossobass, years ago, always recommended sealed sub systems in sealed rooms. The subs 12db an octave rolloff matches perfectly with PVG's 12db gains per octave theoretically giving one a flat in room response to 5hz or lower. You still have to eq someway those freqs above PVG's start point. Your 16db loss from time misalignment above your PVG start point has zero db loss below, hence no change to your vibrometer reading. Then when you compensate by raising the sub level +16db, ULF or below PVG start point will be thunderous. Sound waves are phase dependent only above PVG start point. That how I interpret the graphs. I may be way off base here.
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post #2987 of 3237 Old 03-16-2015, 11:02 PM
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Time alignment should have zero effect from the 1/2 wavelength of the long dimension and rise to to have max effect at frequency of full wavelength of long dimension and all freqs above, in effect, a zero null to max null at an octave above it. Those dimensions make up the room nodes that wreak havoc with our rooms. See above posts last sentence for disclaimer if i"m
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post #2988 of 3237 Old 03-16-2015, 11:19 PM
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Heres another post by Mark Seaton about a decade back on another forum.

"There are changes below where a 1/2 wavelength won't "fit" in the room, usually defined by the longest dimension, top-to-bottom of opposite corners. Below this point you no longer see modal behavior, problems, or variations. What you do see is a gain in LF output for a given subwoofer output. So in fact the result is the opposite: More output, less distortion. In simplest terms you transition to a mode of pressure modulation, where you are basically modulating the pressure in the entire room. Remember that our ears react to air pressure modulations and it doesn't matter what causes the level of modulation, since the observer (us in this case) is exposed to the same changes in pressure as if they were outdoors."
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post #2989 of 3237 Old 03-17-2015, 07:24 AM
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When you are out of phase it creates a null at that frequency but it might create peaks elsewhere. I would run 3-120hz sweeps with it in phase and out and see what happens. Since this talk about phase I am wondering if my 50-80hz region is out of phase from the front to back which creates that peak from 5-30hz? I will mess with it later and find out. It will be so cool that it was because that means it is an easy fix. Since sealing the wall the bass sounds much tighter with zero rattles, it is finally a true baffle wall.

NanoAvr to Outlaw 975
amps-5 Adcom GFA-555's mono's, Sanway FP14K
5 JBL 2447 CD, 5 2352 horns, 3 15 inch 2035 for fronts, 2 15 inch 2032 for surrounds
subs-IB SI 18ht x12
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post #2990 of 3237 Old 03-17-2015, 08:38 AM
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Originally Posted by MKtheater View Post
When you are out of phase it creates a null at that frequency but it might create peaks elsewhere. I would run 3-120hz sweeps with it in phase and out and see what happens. Since this talk about phase I am wondering if my 50-80hz region is out of phase from the front to back which creates that peak from 5-30hz? I will mess with it later and find out. It will be so cool that it was because that means it is an easy fix. Since sealing the wall the bass sounds much tighter with zero rattles, it is finally a true baffle wall.
My graph above is a 5-20k test. You can see the difference. As our rooms are the same size your experiencing the same null I am. Get the subs time aligned and cut the peaks then call it a day. You'll never get the 50-80 perfect without extensive EQing. Which I don't like. Let me save you some time. There's one thing that gives me a nice smooth response there, a bigger room. Since that ain't happening, oh well. I had some success on another build inverting the mains. Totally smooth that region out. Maybe I'll mess around with that when I have time.
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post #2991 of 3237 Old 03-17-2015, 01:41 PM
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My room is 17x14x6.5 but the back 4 feet is 11 inches less in height for seating. I have to make sure my mic is working correctly as the response does not change when I move it 3 feet which it usually does somewhat. My UMIK has no cal files below 10hz so it is a bad representation below 10hz but works great above.
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post #2992 of 3237 Old 03-18-2015, 05:51 PM - Thread Starter
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Good info coolrda!

The question is: when you reach the point where the 1/2 wavelength no longer 'fits' in the room and phase changes have no SPL impact, what is the PVL in this region?

Since there is no SPL impact to changing phase, the only driver that would influence PVL would be distance from the source (1/r^2), where r is the distance. The closer you are to the source, the more prevalent PVL would be, and thus Sound Intensity.

Above the freq. where 1/2 a wavelength 'fits' in the room, both phase and distance would play a factor in PVL and Sound Intensity.

So, what does that mean for ULF frequencies? Nearfield placement to get the most tactile feeling in ULF passband, and for above that 1/2 wavelength freq point, try and find an out of phase scenario to maximize the PVL in that region, as I demonstrated in my tests at 27hz. Since these frequencies (where phase plays an impact) are typically in the LF region, you'll have more headroom to tackle the 'out of phase' scenario and power through it.

Doing it in this manner, would maximize the tactile feeling in your room.
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post #2993 of 3237 Old 03-18-2015, 08:00 PM
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Here are sweeps of my subs front wall and rear subs. I connected the adcom to the rear subs as well to compare.


Green: Adcom rear
lower dark purple: clone rear
Maroon: front w/clone
top light purple: clone all subs




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post #2994 of 3237 Old 03-18-2015, 08:31 PM
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Originally Posted by MKtheater View Post
My UMIK has no cal files below 10hz so it is a bad representation below 10hz but works great above.
Here are my correction values for early 2015 UMIK.
4, 3 and 2hz are extrapolated values.

I lucked out, mine is extremely flat... so these would be absolute minimum correction values (most would need even MORE boost correction. Which for a CSL version would already be covered to 5hz, so no change needed for those folks.)
Up to -7db for 5hz and -20db for 2hz wouldn't be too far out of the question.

2.00 -8.00
3.00 -5.90
4.00 -4.45
5.00 -3.14
6.00 -2.00
7.00 -1.56
8.00 -0.81
9.00 -0.14
10.00 0.00
11.00 0.23
13.00 0.56
14.00 0.65
15.00 0.81
16.00 1.00

Last edited by BassThatHz; 03-18-2015 at 08:36 PM.
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post #2995 of 3237 Old 03-19-2015, 04:59 AM
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That would make sense. The roll off above 50hz is due to the IB type of enclosure.
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post #2996 of 3237 Old 03-19-2015, 06:29 AM - Thread Starter
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Quote:
Originally Posted by MKtheater View Post
Here are sweeps of my subs front wall and rear subs. I connected the adcom to the rear subs as well to compare.


Green: Adcom rear
lower dark purple: clone rear
Maroon: front w/clone
top light purple: clone all subs




Looks like your front and rear subs are perfectly in phase as the combination of the two sum to higher db for all frequencies.

It would be interesting to see you play with phase so that the sum of the two reduces output in the LF range when combined...and then you can raise the entire level of that range until your satisfied with your response. This should net you more tactile feedback.

Since you have gobs of headroom, you won't be power limited and essentially turn that extra headroom (that you never use) into tactile feel while keeping your response generally the same.
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post #2997 of 3237 Old 03-19-2015, 07:00 AM
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I am not sure I can mess with phase like that. I don't have independent control of both arrays as they are one big system. I don't need more tactile effects. I have not tightened my door handle which always falls off now to add to the experience! When I level match my subs to my speakers I level match at the crossover so when I am flat I have a 15 dBs boost from 7-30hz and flat to 3 hz!
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post #2998 of 3237 Old 03-19-2015, 07:12 AM - Thread Starter
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I don't need more tactile effects.
Blaspheme!

Do you have the clone bridged? One channel then? if so, yes...don't think you could mess with phase. If it's two channels, then I think your nanoavr should be able to do it.
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post #2999 of 3237 Old 03-19-2015, 07:30 AM
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I have one LFE out split to each channel of the clone. I could not connect all drivers to a single channel in bridged mode unless there is a way to do it on the amp end. The Nano has phase on the sub out I can play with and see what happens. I still don't understand how tactile effects go up with the same SPL levels. One uses more power out of phase than in phase.
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post #3000 of 3237 Old 03-19-2015, 07:55 AM - Thread Starter
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I have one LFE out split to each channel of the clone. I could not connect all drivers to a single channel in bridged mode unless there is a way to do it on the amp end. The Nano has phase on the sub out I can play with and see what happens. I still don't understand how tactile effects go up with the same SPL levels. One uses more power out of phase than in phase.
It's because PVL levels go up when you use more power in the nearfield, and the out of phase condition allows you to use more power but with the same SPL level.

Look at my test here. Same SPL level, same distances, but Tactile Feedback is much different as I'm taking advantage of the out of phase condition to use more power, and thus generate more Sound Intensity.
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