# Dr Strangelove, OR how I learned to stop worrying and love EQ



## acoustat6 (Mar 7, 2008)

Hello Everyone, It has been a while since I have posted on the great HT Shack site with the wonderful Room EQ Wizard! :bigsmile: It has been a few years since I had started to use REW and EQ and feel that it has been the best advancement in the sound of my system. I have recently started to use full range EQ, which has been a desire of mine since I first became interested in audio playback in the late 70s. My first sytem was all SAE with one of their EQs. I still use some of that equipment today.
This post will be my blog about my experiences with the Room EQ Wizard and my now fully realized, full range EQed system. 
I have posted my system specs in a prior post, but will repost it again.
MY system is a tri amped 3 way with an electronic crossover, using tube and solid state equipment that is both modern and vintage. Hey, it was not vintage when I bought it in 1977! Where did that time go?lddude:

The equipment consists of:
Shelter 901 phono cartridge,

Eminent Technologies ET2 tonearm

VPI TNT 2 turntable,

Bent step up transformers,

Hagerman Trumpet tube mm phono stage,

Goldpoint stepped attenuators,

Marchand XM126 3 way crossover with seperate power supply,

Behringer FBQ 2496 feeding an SAE 2600 which drives a set of 10 per side Bohlender Graebner Neo 8 drivers for the high freq crossed over at 1700hz,

Behringer FBQ 2496 feeding a pair of Acoustat direct drive amps driving a pair of Acoustat 6 electrostatic speakers. I have owned these since 1985.,

Behringer FBQ2496 into a Marchand Bassis EQ which then goes to a pair of SAE 2400L amps. Each amp controls a set of woofers consisting of 16 eight inch custom made Eminence drivers. There are 8 forward facing and 8 rear facing drivers per side for a total of 32 drivers. They are in full stereo crossed over to the Acoustats at 85hz. 

Room EQ Wizard and my ears!

Attached are a few pictures of the system and new photos will be coming soon to show the additional Behringers and system as it currently is. This is located in my "barn" not my house. The room has been fully bass trapped as well as using broadband traps.
This thread will be an ongoing commentary of my thoughts about my stereo, REW and full range Eq. I hope you enjoy.:T


And now some quotes about my Strangelove...

Major T. J. "King" Kong: Well, I've been to one world fair, a picnic, and a rodeo, and that's the stupidest thing I ever heard come over a set of loudspeakers. You sure you got today's EQ codes? 

Miss Scott: It's 3 o'clock in the morning! 
General "Buck" Turgidson: Weh-heh-heh-ll, the Air Force never sleeps. 
Miss Scott: Buck, honey, I'm not sleepy either... 
General "Buck" Turgidson: I know how it is, baby. Tell you what you do: you just start your countdown, and old Bucky'll be back here before you can say "Room EQ Wizard!" 

General "Buck" Turgidson: Gee, I wish we had one of them REW machines. 

General "Buck" Turgidson: Sir, you can't let him in here. He'll see everything. He'll see the REW! 

General Jack D. Ripper: EQ is the most monstrously conceived and dangerous communist plot we have ever had to face. 

General "Buck" Turgidson: Mr. President, we must not allow a REW gap! 

General Jack D. Ripper: Mandrake, have you ever seen a Commie use REW?
Group Capt. Lionel Mandrake: Well, no, I can't say I have. 

Dr. Strangelove: Sir! I have a plan! 
[standing up from his wheelchair] 
Dr. Strangelove: Mein Führer! I can use REW and EQ!


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## Wayne A. Pflughaupt (Apr 13, 2006)

Interesting set up there, Bob, and welcome back to the Forum! 

Just curious, why do you have all your EQs post-crossover? The standard arrangement is to EQ in front of the crossover. That way one EQ can do the full frequency spectrum.

I take it you like the FBQ2496? I've always been a bit leery of them because of their low price and the -10 dB / +4 switches, so I've never used one. Just curious, how is their background noise when in the +4 position?

I'm also wondering, what does the Marchand Bassis do for you that the 2496 won't?

Regards,
Wayne


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## acoustat6 (Mar 7, 2008)

Hi Wayne, and thanks for the welcome "back" (never stopped lurking).

The reason I use the separate Behringers is so that I can control the input levels independently to each unit so I can level match them and therefore the speakers also.

Yes I do like the FBQ2496. It adds just a tiny bit of hiss close up to the speaker. It is in +4db mode. It does not distort, sound "bad" or loose any transparency. So the tiny little bit of hiss is completely overshadowed by what it does for the positive sound of my system.

Low price bother you? Buy 3 of them!:devil:

The marchand Bassis is a Linkwitz transform which I use to boost the low freq of my sealed woofer system with its inherent rolloff of 6db per octave. It can add up to 24db of boost. Please note that I use a "passive preamp", the Goldpoint attenuators, so I need to get gain from somewhere else other than the 44db from the phono preamp.

Bob
PHP143


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## acoustat6 (Mar 7, 2008)

Hello, as you can see from my posts that EQ has been an interest of mine since my early days of audio. It was only with the realization and use of REW that has made EQ as attractive as it is to me now. Full range EQ to be exact. I had always wondered why my previous attempts at full range EQ was unsuccessful...it was accuracy or more likely lack of accuracy. This is what REW provides, accuracy.:T

I will, with this thread, relate my thoughts and experiences with REW and now full range EQ as best as I can. It will include my audio observations as well as measurements and how they relate to what I am hearing. 

I my previous threads "my in room response" and "my new in room response" I was using one Behringer for the subs only, but realizing the resounding success with the bass, I knew that full range EQ was not far behind. 

It has only been several weeks since I bought a 2nd Behringer which I started to use on my high freq section of my system. And finally a 3rd Behringer for the mid range of my system. I was initally hesitant and a bit wary of using full range EQ as it has been well ingrained in the audiophile mind that full range EQ was a non starter for various reasons. 

I was also a bit concerned about using the Behringer for anything but the subs, as it has been well noted by various users that the Behringer is not of high enough quality for freq above the bass range. Of course there is no doubt that there are more expensive equalizers and probably better sounding units... I will let you know when I can find and afford three, high quality, thousand dollar equalizers.:devil: And who knows, I may..........

Bob 
PHP143
"if the first one hundred db suck, why continue?

President Merkin Muffley: You mean people could actually EQ full range? 
Dr. Strangelove: It would not be difficult, Mein Führer. Equalizers could - heh, I'm sorry, Mr. President - Equalizers can EQ full range.


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## Wayne A. Pflughaupt (Apr 13, 2006)

acoustat6 said:


> The reason I use the separate Behringers is so that I can control the input levels independently to each unit so I can level match them and therefore the speakers also.


Not following the logic there. I can’t think of a reason why the EQ’s need independent level control. Typically all gain controls in a multi-amped system are provided by the crossover and/or amplifiers. This can be accomplished with the EQ in front of the crossover.



> And finally a 3rd Behringer for the mid range of my system. I was initally hesitant and a bit wary of using full range EQ as it has been well ingrained in the audiophile mind that full range EQ was a non starter for various reasons.


Yup, the “no EQ” thing is a familiar refrain. I’ve always thought people who arrived at this conclusion did so because they had no idea what they were doing and with their EQ experiments just mucked things up. Or they were using a poor-quality unit. Or both…



> I was also a bit concerned about using the Behringer for anything but the subs, as it has been well noted by various users that the Behringer is not of high enough quality for freq above the bass range.


That has typically been the sentiment of the DSP-1124 BFD, not the 2496. The latter hasn’t been nearly as popular for subwoofer EQing because it’s more expensive and IMO isn’t as precise because it doesn’t have as many bandwidth settings as the DSP-1124. You’re the first person I’ve ever seen use the 2496 full-range, so I’m certainly interested in your findings / experiments.



> I will let you know when I can find and afford three, high quality, thousand dollar equalizers.


Yamaha YPD2006. For more see the links in my post in the BFD Alternatives thread for more info. If you’re patient you can find them on eBay for $150 or less. Not bad for an equalizer that list-priced for over $2000. If possible you want to find one from a permanent installation, not one that was used in a rental department or in a touring system.

Regards,
Wayne


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## acoustat6 (Mar 7, 2008)

Hi Wayne, I did try Rane PE 17 and was unable to get them to work in my system as I could not eliminate a loud hum. Or was it a buzz? I did try a number of things to eliminate it and was unsuccessful. You may be correct about the Yamaha being a better unit, but I am not unhappy with the Behringers at this time. 
There is a reason why I use/need the three EQs....

Bob


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## KalaniP (Dec 17, 2008)

Wayne A. Pflughaupt said:


> Yamaha YPD2006. For more see the links in my post in the BFD Alternatives thread for more info. If you’re patient you can find them on eBay for $150 or less. Not bad for an equalizer that list-priced for over $2000. If possible you want to find one from a permanent installation, not one that was used in a rental department or in a touring system.


Is this Yamaha EQ better (cleaner) than the Behringers, and suitable for sub EQ as well, or are the Behringers as good as it gets at that level (without spending loads of dough)?


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## SALESEPHOTO (Jul 5, 2009)

Dr Strangelove, is that the movie where the cowboy rides the atomic bomb as its dropped out of plane,with
peter sellers or am I thinking of some other movie?


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## KalaniP (Dec 17, 2008)

SALESEPHOTO said:


> Dr Strangelove, is that the movie where the cowboy rides the atomic bomb as its dropped out of plane,with
> peter sellers or am I thinking of some other movie?


That's the one.


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## Wayne A. Pflughaupt (Apr 13, 2006)

KalaniP said:


> Is this Yamaha EQ better (cleaner) than the Behringers, and suitable for sub EQ as well, or are the Behringers as good as it gets at that level (without spending loads of dough)?


”Clean” isn’t really an issue with subwoofer EQ. The DSP-1124 (and its current FBQ1000 replacement) is best for subwoofers (read most precise), since it offers the most frequency stops and bandwidth settings. For frequency settings, both Behringers have 1/60-octave resolution (i.e. 60 frequency settings per octave), while the Yamaha is 1/24-octave. For bandwidth settings, the BFD has 11 in the critical range between 1/6 and 1/3-octave (where most sub EQ filters are set), compared to 7 for the Yamaha and a mere 5 for the FBQ-2496.

That said, I haven’t had any problems getting the response I want using the Yamaha, and I haven’t heard any complaints about the FBQ2496.

Regards,
Wayne


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## KalaniP (Dec 17, 2008)

Wayne A. Pflughaupt said:


> ”Clean” isn’t really an issue with subwoofer EQ. The DSP-1124 (and its current FBQ1000 replacement) is best for subwoofers (read most precise), since it offers the most frequency stops and bandwidth settings. For frequency settings, both Behringers have 1/60-octave resolution (i.e. 60 frequency settings per octave), while the Yamaha is 1/24-octave. For bandwidth settings, the BFD has 11 in the critical range between 1/6 and 1/3-octave (where most sub EQ filters are set), compared to 7 for the Yamaha and a mere 5 for the FBQ-2496.
> 
> That said, I haven’t had any problems getting the response I want using the Yamaha, and I haven’t heard any complaints about the FBQ2496.
> 
> ...


Thx!


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## acoustat6 (Mar 7, 2008)

Hello all, Dr Strangelove is probably my favorite movie from my favorite producer Stanley Kubrick. Yes, Slim Pickins riding the bomb is a real classic.

My "Strangelove" is EQ and SPL. I feel that it is the most important factor in good sound. Regardless of speakers and amplification, which are important, the point is that untill this is addressed, great sound is impossible to achieve. It also levels the playing field and helps you find your way in finding a good speaker and amp mating.

Wayne asked why I am using three EQs, post crossover, which is a good question. The answer is that is the only way I can see to achieve a smooth in room response and be able to tune my three way speaker system. As well as I like lots of flashing lights:bigsmile:

What I do is run my three sets of speakers individually and full range mode ( ie: no crossover and all other speakers off) this gives me a REW graph of my DIY subs, Acoustat 6 and the Bohlender Neo 8s individual freq response. None of the speakers on their own are capable of running full range 20-20k. If they were I would use just one set of full range drivers. I have never seen a single driver capable of "full range", its not possible. Even the big Acoustats are unable to achieve this. I have no idea how anyone can call a single 4 or 6 inch driver or any driver of any size regardless of type full range, it does not and cannot be true or happen:devil:.

Anyway, then I have the freq response of each set of drivers and EQ them flat and then I set the crossover level. The important part of this is that I can remove all of the nulls in my response whether they are room nulls or freq response problems from the speaker/amp combination! This way I have a very smooth response with no dips anywhere! This cannot be done with the EQ pre crossover.

Then the only question is... what is a great freq response?onder: 


Bob 
PHP143
If the first one hundred db suck, why continue?


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## LastButNotLeast (Sep 14, 2011)

You've seen the threads on house curves, no?


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## acoustat6 (Mar 7, 2008)

Hi LBNL, I have read the articles on house curves. I do employ a low freq house curve, my woofers are up 15db at 20 hz and it is a great sound. Now that I am capable of full range Eq I am wondering what is a good freq response for the next eight octaves. I don't believe that the article really answers that question.

First off I believe we are looking for a smooth response, + or- 3 to 4db is great and within reason. 
Thats the "easy" part. Though I personally would be aiming at + or - 2db through the entire freq range.

But the real question is what freq response? Waynes article has a suggestion as well as others I have read about. Such as my favorite, freq response does not matter, as we are listening to music not test signals.  Then to the X curve, the british BBC curve, the smiley face, flat, whatever sounds good, Fletcher Munson etc.
What I am looking to do is approach a smooth flat response and then be able to manipulate it from there. 

The reason for all of this? I can only say that every time I have experienced a smoother or "better" freq response the more I enjoyed the speakers/systems sound. Regardless of the speakers or electronics. And the system sounded more "musical" as well as a number of audiophile terms...
Wish me luck. :T

Bob
PHP143


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## LastButNotLeast (Sep 14, 2011)

I'm far from an expert (and, frankly, have no desire to achieve that level in this hobby), but a quick perusal of Everest's "Master Handbook of Acoustics" suggests (to me, anyway) that a perfectly flat frequency response is probably the least of your worries. It's a great place to start, but there are so many other factors that control the "sound" that you're probably better off focusing on some of them.
Have fun.
Michael


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## acoustat6 (Mar 7, 2008)

Hello, I briefly mentioned in my last post my one of the positive effects of EQ. Besides the fact that I like flashing lights and buttons:bigsmile:! 

I used the word musical. But what does that imply? To me that means that the sound is:

more dynamic, both macro and micro

all instruments as well as voices are more complete, more tonally correct

the noise floor is lower, the system is "blacker"

there is better extension at both freq extremes

I will discuss these, individually, in further posts

If you use EQ for the low freq and and experienced these effects, why would it be any different for the next eight octaves?

Bob
PHP143

PS: LBNL, unless you have something constructive to say, unlike "but there are so many other factors that control the "sound" that you're probably better off focusing on some of them." Perhaps you would like to name them?
Then step away from the keyboard. 
Freq response and REW is what we are talking about on this forum. 
Being that you "are far from an expert" perhaps you should be reading only, instead of writing .


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## LastButNotLeast (Sep 14, 2011)

Okay.


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## jpv (Jan 19, 2008)

Bob,
One advantage I see in using 3 Behringers, is it gives you the flexibility to adjust for frequency response where the subs/Acoustat and Acoustat/Neo 8s share frequency.
If the Behringer was placed before the crossover any adjustments made would effect both speakers.
By looking at each speaker on its own, you can adjust any peak or dip individually. Say you have a peak at 1500Hz. and it is caused by the Acoustat and not the Neo 8s you should apply the filter for the Acoustats. 
As you said, the real question is what type of response is desirable. Perfectly flat is not good. We know that, just look at your house curve. My feeling is if your left and right speakers are within a few db of each other your OK. This will help with keeping your imaging stable. If not, as the music is playing, your mind is drawn to the louder sound causing the sound to shift to one side and creating fat images or instruments that move. Also, there's a frequence range that will sound acceptable. Maybe the Fletcher Munson, BBC curve, slightly tilted down? I think it is partly personal, room and system related. 
JPV


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## acoustat6 (Mar 7, 2008)

Hi JPV, That is correct, I EQ each range/speakers individually, for that reason. 

What it also does, it allows me to eliminate all dips in the freq response! Through the entire freq range! But then of course you need to use many filters. I currently have 6-7 filters on each Behringer for the low and mid range. I have not EQed the high freq yet, though the Behringer is in the system and has 3 filters at this time. I expect that the Bohlenders (high freq) will also require at least 7 filters. Therefor I believe I will end up using, most likely, 20 to 25 filters for full range EQ.

I think the main reason I do this is so I do not have to use any gain/positive filters in EQing. And then wind up with a "perfectly" flat response across the entire freq range of 20-20khz. This will be my baseline starting point. I can then either add a little more negative filter to bring further down a freq range. Or I can relax the appropriate filters to bring up the desired freq range. To do this you do need to use seperate Behringers for "each" set of drivers. IE: if you have a sub and a set of two way speakers or three way speakers (with their own internal crossovers) you would need two Behringers. But since I have a three way crossover I can apply the EQ to each set of drivers individually.

I will, once I have some time, do a set of comprehensive REW measurements showing this process. 

You mention level matching L and R speakers and you are correct, when I have enough time, that too is on my to do list.

The "jury is still out" (they are not even in the building yet!) as to what a "great" freq response, that will take quite a bit of listening and measuring time...years? Dont worry I have the timelddude:!
But it is some combination of Fletcher Munson and other factors on how we hear. 

You are also correct that there is some leeway due to room, personal preference and of course system. I just know that a wild and erratic freq response that is imposed upon the listener by the room and speaker/electronics interactions is wrong. It proved to be wrong for the low freq, I know it is wrong for the next eight octaves. 


Bob
PHP143
If the first one hundred db suck, why continue?


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## jpv (Jan 19, 2008)

Bob,
We could talk for hours about the proper curves, 36,26,36:bigsmile: It will be interesting to see what you end up with when you are thru.
Jpv


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## acoustat6 (Mar 7, 2008)

Hello, JPV, yes it will be interesting what I "discover" regarding a freq response that I like. What I plan to do also is to have several curves set in the Behringer. 
36-24-36, sounds like a good place to start:R

I mentioned that one aspect of the new improved smoother freq response of the Acoustats was increased dynamics both macro and micro. It reminds me of when I first started to EQ my subs, I was not so sure that it was the direction to go. Who had not thought this initially? It was that as I eliminated the first major peak in my low freq response the dynamics actually sounded to have decreased. How could that be? But as I lost the peaks and as where I could find an album that "matched" that in room peak and rattle the room AT THAT FREQ, the system appeared dynamic. 
Is that dynamics? 
A single peak we all know sounds boomy so perhaps two, three or four smaller peaks sound more musical. 
One peak is boom. 
Two peaks is pace. 
Three peaks is rhythm. 
And four peaks is timing. 
Eliminate all of the peaks and you discover the real hidden music.

But how does this relate to increased micro and macro dynamics?

As the peaks are reduced you hear more info from the missing nulls and the obscuring of music from the overshadowing of the peaks. There appears to be more of a natural rise and fall of the macro dynamic music as opposed to just a room shaking peak. If you have room shake/shudder and vibrating objects in the room this is a clear indicator of low freq peaks.

In the micro dynamics, these small dynamics that are a natural part of an instruments sound are not obsured by the overpowering peaks that hide detail.

The same would be true for the next eight octaves, except that the room shake is not the problem. The effect is continued loss of dynamics, listener fatigue and as always loss of detail in the music. This is also closely related to your ultimate listenenig levels. The larger the peaks the more this holds back your in room listening level.

Think of a peak (anywhere in your freq response) as the slow car in the third lane. It will always hold back the the other cars from 

Also think of peaks and dips as a mountain range (freq response), easy enough to do. Not very easy to traverse (listen to). But if you smooth out the mountains to fill in the valleys, you still have the same amount of earth(energy), but look how much easier it is to traverse(smoother). If you were looking for a view from the mountain top and now it is not high enough, you just need to raise the plateau. Not look for another mountain to hold you back.

Bob
PHP143


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## acoustat6 (Mar 7, 2008)

Hello again, So now I have increased dynamics and have also experienced decreased noise. Almost a miracle! But how does a smoother freq response reduce noise while at the same time increasing dynamics?

I am sure that more than a few of us have observed the easiest to observe noise reduction or problem is with 60hz line noise. A peak at 60hz will simply have you hearing more noise than you would when that peak is reduced. 

When I applied EQ to my midrange I was surprised in hearing a reduction of noise. I had thought that if one were reducing peaks, and therefore reducing noise at the freq range those peaks are in, that the inverse of that would be that as the freq response dips are brought up in level that it would be a "wash". 
IE: as you reduce noise from one peak that it would be countered by the increase in noise in the region that was brought up in level. And therefor the amount of noise would be equal. While that must be strictly true, it does not sound that way. MY system sounds more quiet, "blacker".

I did a little experiment and added 1 to 4 filters at various freq in the midrange with various Qs and gains, as the filters were added it was quite obvious that any peak in any freq range increased noise levels, DUH now that seems obvious:yikes:

Just another reason not to tolerate poor freq response. 

Bob
PHP143


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## jpv (Jan 19, 2008)

Bob,
Interesting observation on the floor noise. If you run the RTA with the system not on, with the system on with filters in, and with the filters out do you see any changes?
My quess is you would in each case. Noise comes from a lot of area that are not so obvious. The lights, Dimmer switch, compressors, heating and cooling equipment. etc all add to the floor noise. 
By making your system smoother by reducing peaks you may be reducing the noise injected into your stereo by other equipment. I wonder if you had a 60 hz peak and you lower it with you Behringer will that reduce the harmonics of that frequency?
JPV


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## acoustat6 (Mar 7, 2008)

Hi JPV, I have not used the RTA to check the noise floor in that way. That would be interesting. I have no other electronics on when listening, this system is in my "barn" and there are no lights, refrigerators etc on while listening. Well there is a compressor for the ET2 tonearm, but it only runs once, every 20 min or so.

All of our systems have "noise" thruout the freq spectrum. So reducing a peak will reduce the noise at that freq. 

The interesting part is that while I heard a slight increase in noise after installing the Behringer at the speaker (listening close, within 1 ft of the speaker), the "noise" or noise floor is quieter at the seated position, which is where I listen, and where it matters most to me. 

Of course that makes sense when you consider the fact that if you listen elsewhere in the room, system noise is decidedly worse. 
This is what occurs when you use equalization. 
When you equalize you are just moving peaks to other parts of the room, while you enjoy a nice non peak zone:bigsmile:.

What I find most interesting is that, since a decrease of noise because of a peak, should be countered by an increase of noise, because of a dip. They should equal out.onder: And I am sure they do, but the sound is much improved in this manner. I guess its a noise free zone:bigsmile:


Bob


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