Axiom Home Page Forums General Discussion Home Theater 600 Twin

I just received an email from Noreen, the 600 and cables are going out today, so it should arrive here Thursday morning. The BFD will be here tomorrow, should be able to start with concealing the cables on Friday and do the basic set up and see how the pair sounds. Doug McBride has offered to travel down here and help out with the set up of the BFD and 600s on the 14th, so have a week to have everything in place. Will take pics of the new toys when they arrive and post on the HT pages.
Have been thinking about a name for the HT system for the web page, any suggestions would be helpful.

You're nuts. I love it.

That is awesome Dennis, you'll be one happy camper very soon..

Dennis - your are delightfully twisted!!! When you get the pictures, be sure to take several of the house levitating.

Ray

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been thinking about a name for the HT system

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how bout.. 'Halo'ed be thy name.... ok, just trying to help.

or 'Shallow Halo'..?

or better yet.. call it...

"i DARE you to f@%king sit right there!!!"

bigjohn

And I was just thinking HAX.
You go bigjohn!

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Halo'ed be thy name

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That's funny.

ha-lo and welcome to my theater

I like what Ray said..."Delightfully Twisted"....

I like HAX. Halo+Axiom=HAX

Another variation is HAX^max (pronounced "Hax to the max")

One I thought of was HAH............Halo Axiom Heaven. But one def of haven is " a place of safety" LOL

Hah!

How about "dB Dream"? If your last name starts with B, it's even more fitting.

You oughta hear him play that HAX.
I'm HAXed out.
Careful with that HAX Eugene. (Floyd reference)

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"i DARE you to f@%king sit right there!!!"

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LOL, bigjohn gets my vote!

Added a few pics on the web pages of the latest oak work, trying to gt it finsihed by Thursday.

Dead sexy.

Ditto! I must admit it took me awhile to figure out what that huge cable was. I kept thinking "DAMN! Dennis has really spent some money on speaker cables." But, I got it (I think). I'll not reveal, in case others are still trying to figure it out. I'm fully aware that I may be the only one who didn't know what it is right off the bat. Hey! I'm old!

I don't have a name just yet but how about a release form-

Danger: High voltage and volume. Please do not enter if you are pregnant or of childbearing age; have heart trouble, a pacemaker, or high blood pressure; suffer from dizziness or seizures. Not liable for subsequent hearing loss, shattered glasses, teeth, or glass eyes.

Please turn off all hearing aids.

If after reading this warning you still chose to freely enter this domicile, you hereby release the owner of all forms of liability.

Enjoy the show!

Or the German warning that I've always had up in any production booth I've worked in:

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ACHTUNG - ALLES LOOKENPEEPERS

Das Machine is nicht fur gefingerpoken und mittengrabben. Ist easy schnappen der springenwerk, blowenfusen und poppencorken mit spitzensparken. Ist nicht fur gewerken by das dummkopfen. Das rubbernecken sightseeren musten keepen das cotten-pickenen hands in das pockets - relaxen und watchen das blinkenlights.
--------------------------------

Bren R.

In factories you get yellow warning tape in a circle around each piece of dangerous equipment, showing you how far you need to stay away to avoid injury.

Now.. when you go into supermarkets you see these neat graphic overlays laid down on the tile. Looks like you're walking over a box of Cheerios or something but the floor is smooth.

How about black and yellow "danger" circles around each speaker, along with the appropriate warning signs ?

Post these signs (1) and (2) near entrances to your home.

You can make your own signs at this website (free registration required).

Very cool! thanks for the link...

Thanks Peter, may make some for the front door, use them when we have BBQs.

The BFD just arrived and took some quick pics of it, they are on the web page if interested. Back to playing carpenter.

I got my BFD two weeks ago (I think) and was going to set it up this past weekend. I never got further than creating a disc of bass tones (and two of decent bass-music), taking my initial measurements and moving my sub to a better location and the M60s a bit for fine-tuning.

I was going to post a "Father of all Bass Posts" showing how I was using a spectrum analzer, my charts and graphs, etc...but since I didn't finish setting everything up.....

I hadn't even gotten as far as realizing the rack ears could be removed... or did you take a hacksaw to them?

Nah, no hacksaw, they each have two philip head screws. I just put it in the cabinet to keep it safe for now. Will be working on it later in the week or weekend, and deciding on where it lives and if I want to make some wood mounts for attaching it. *shrug*

What, again, does the BFD do? In any event it sounds very impressive...

You mean besides allowing one to spend countless hours of treaking with it ? LOL Its a parametric equalizer, and the people whom I have used for advice, have recommended a parametric over a standard EQ when they are used on subs.

obviously, its a machine that is made for use in more industrial scale audio set-ups. it has XLR connections, and those are not common on standard, run of the mill equipment. i would bet the manual for that thing is huge.

bigjohn

"What, again, does the BFD do? In any event it sounds very impressive... "

Management summary: "it sounds better when you are done".

Some details if you want to read on:

As Dennis said, the BFD (no, it doesn't stand for what you think - rather it is "Behringer Feedback Destroyer") is, among other things, a parametric equalizer. For all practical purposes, it allows you to fine tune the frequency response (FR) of your listening environment. The goal is to get rid of the peaks and valleys of sound pressure (loud and soft areas) in the bass region of your overall room FR. Due to room effects, some bass frequencies can overpower (peaks) what you are hearing in the bass range, or conversely, you can lose bass in the range where you have dips.

Almost any HT can benefit and get better bass with some form of equalization. Even great subs like the Axiom EPs (and of course my SVSs :->) that are designed and tested to have an essentially "flat" FR in their range do this in an anechoic environment. Put them into a room and suddenly you can find yourself getting some frequencies boosted and others eaten by the way the bass frequencies positively or negatively reinforce each other (remember your wave theory in physics?) as they bounce off of walls, ceilings, couches, marble floors (like Dennis has), etc. Add large openings into other parts of the house, drapes, pictures on the walls - and you can see how crazy it can get.

In order to counteract the effects of the room on bass, what we do is measure the FR of the room using test tones and a SPL meter. We plot those on a graph of frequency versus SPL. In an anechoic environment, what we would see is a fairly flat line at a given SPL across the sampled frequencies that usually match the manufacturer's specs pretty well. In the real world, we'll see places where the SPL will be +/- several dB (sometimes 10 - 15 or more in extreme cases) which of course does not allow you to faithfully reproduce the bass from the source material.

Using an equalizer like the BFD, we can cut the peaks and boost the valleys (unless it is a null - another story) to get to as close to a flat FR as possible. We may then apply a "house curve" to the bass that essentially boosts (or doesn't cut as much if needed) the lower frequencies since the human ear is less sensitive to bass as the frequencies get lower. What the result will be is a uniform reproduction of bass, in your room, that has the effect of cutting out "boominess" and tightens up the perceived bass response significantly.

A parametric equalizer differs from a graphic equalizer (you've all seen graphic equalizers - they are the gizmo's with all the sliders at different frequencies to cut and boost the sound at those frequencies) in that it allows you to arbitrarily set the center frequency of the band you are equalizing, and to apply a variable width of frequencies around that mid-point to which you will then apply boost or cuts. Graphic equalizers are less flexible due to the fixed nature of frequencies that they can affect, and the width of the frequencies they affect.

EQing a room for bass is part science and part art form. I know I've EQ'ed my room many times and gotten different results each time - some better and some worse. In any case it is simple to see what your room looks like if you have a SPL meter (we all do, don't we?) and some test tones. We play the test tones (usually start at 16Hz and go up at 1/6 octave intervals) and graph the result. If there are wild swings, or significant peaks and valleys in the resulting graph, you will probably realize benefits by applying some EQ.

Hope that helps.

Cheers,

Doug

Wow-
Nice post, Doug!

Thanks Mark, much appreciated. As you know, this only touches the surface of the topic. It is fun though!

BTW, if anyone is interested in learning more about the BFD, its capabilities and its complexities, check out:

http://www.snapbug.ws/bfd.htm

if you've not run across it before. It also has some nifty tutorials referenced by the owner of the site, and links to test tones you can download and burn on to a CD. You can also find a link to a handy Excel spreadsheet that can be used in plotting your room FR, with built-in correction factors for the Radio Shack SPL meter (required for the low frequencies we're working with in EQ'ing bass).

Cheers,

Doug

For the Axiom owners in the bay area, Doug has kindly offered his aisstance in setting up the twins and the plan is to do this on Thursday 6/14 starting about 9am. Any one in the area interested in bass set up is welcome as well.

Wish I could be there. I'm sure my room is a nightmare if I were to take all the readings and graph them. I know it sounded much better in my last apartment than it does now.

We have a guest room/bath and its only a 5 hour drive, as long as you get out of the LA area before rush hour.

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I was going to post a "Father of all Bass Posts" showing how I was using a spectrum analyzer, my charts and graphs, etc...but since I didn't finish setting everything up.....

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If it's even half as comprehensive/insightful as your previous "mother of all" posts, we're in for a treat.

I'd be interested in hearing your impressions Mark. I was about to go pick up a BFD the other day and it just so happened the store wasn't opened so I am planning on going this weekend. Unfortunately, my TV is now on the fritz and in the shop so I am waiting to do my measurements with the Rives test cd until everything is back in it's rightful place.

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I'd be interested in hearing your impressions Mark.

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Unfortunately, I won't be able to do anything soon. It's sitting in my rack in "bypass" mode, as I only got the preliminary stuff done.

As I've mentioned a few times here (!), my little square room sux. I really need to find a way to diffuse/absorb some big peaks, and I haven't figured out what to do about the bass nulls yet. After reading so many good things about the BFD, I figured it's worth a try for my bass issues. The plan will be to tame those huge peaks so I can bring the overall level higher…hopefully helping some of the nulls and valleys.

As mentioned previously, I started by creating a test disc of tones followed by some production and commercial music samples for bass listening. When all was said and done, I ended up with three discs of tracks. I also redesigned the bass frequency plot I made to reflect the finer resolution of these samples. So I was finally ready to start charting test tones, but thought that I had better absolutely confirm the sub location before the BFD comes into play. So, after testing and listening, I did end up moving the sub to a new location. The results are only marginally better, but right now I'll take "better" as "better".

So there sits the BFD. My "before" charts are plotted for the three primary listening locations, the BFD is installed, but I have no time to learn and adjust the unit. I'll be gone to a "family thing" in NY for a 3-day weekend and, considering I'm backed up now, I know I'll be even further backed up in my work when I return.

I'm irritated that the fine tuning is taking me so long with the whole HT….. which is entirely due to my lack of free time. It's kind of sad actually that it took me so long to fine tune my speaker positions (I've had my system since last Fall and only tweaked the M60s' positions this past weekend, to good result I'll add). I still have such basic things to do as finish programming my MX700… I think Ray gave up on me!

And yet, I still can't help thinking how much fun it could be to tame this room and write another "parent" post…. Though it really will be nowhere near the length of the last one. Realistically, it just might be a month before that actually happens!

I can't personally vouch for the BFD, but I would still recommend it to others based on so many other positive results others have reported. My biggest concern was that, in my room, the bass changes significantly in just a few feet as I walk around the room. My "before" metering has left me feeling optimistic about the results I might get: Though there are differences across the three main seats, they're not nearly as significant as in other areas of the room. Meaning, in other words, that the three seats are sharing "variations" of the same peaks and therefore I can hope the BFD will improve ALL three seating positions… not one at the loss of another as I first feared.

I'll post… and there will be lots of pix…. But it might not be too soon! Don't wait for me!

Mark brings up a good point that I didn't mention in my previous post and that is doing some experimenting with sub (and speaker) location can tame the room a bit.

As I mentioned to Dennis, EQ is not always necessary and the type of EQ device doesn't always have to be parametric or a BFD. Doing some measurements and playing with sub position in the room is always the best place to start, not to mention if you do decide to EQ at some point, it can give you tremendous insight into the behavior of your room so you can use both position and EQ, as well as treatments, to get things more under control. This assumes though that you know how far out of control things are in the first place.

The neat thing about the equalizers we use for bass, and the thing that makes them a must for tweakers is how cheap they are (relative to our other toys that is...). For $100 you can get a lot of value if you've got a crazy room, or if nothing else have the peace of mind that you've done what you can with what you've got to improve your low end (bass, that is). In my case it was also necessary due to the fact my subs are where they are due to room layout and a small dose of WAF, so I had to go the EQ route just because I can't move the subs. Also since mine are not co-located, it was almost a given I was going to have issues.

For bass heads, or those that just love the punch of a good movie soundtrack, doing a bass FR plot is just the next step after setting speaker levels. And, since we already have the tools to do the measurements (the biggest deal is just having a SPL meter), it's a straightforward exercise.

Maybe when Mark is done and has posted his pics, we'll see his room looks like Axiom's anechoic chamber (extreme room treatment as we like to say), but the FR will be ruler flat... :-)

Enjoy the bass,

Doug

About to call FedEx and see where the driver is, is only about 3 hours late. Well waiting, decided on where to install the BFD, so after an hour with a coping saw, hammer, and chisel, its in place. Posted a couple pictures of it on the web page, opinions are welcome.

Thanks for the info on the BFD, by the way. Very informative post. Is there ever an end to the tweaking?

Man I gotta say it, I checked out your system website, its killer. The room you have it in is magnificent

Thanks for the compliments, going back to working on the marble tile this week, my most favorite thing. lol