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post #1 of 128 Old 01-18-2014, 09:02 PM - Thread Starter
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I was referred to you guys for my subwoofer needs. I have a basement theater (roughly 2500 cu ft) that needs proper bass. Right now I'm limping along with a crappy 10" sub I bought for $125. Well, after some quick research I decided I could afford 2 SVS PB-2000's. However, I'm quite handy with my tools. As such, I was told to come to you guys for my needs.

See my signature for my theater build thread. You can get a quick look at the pics to see how it's laid out. I have about 26" from the back wall to my screen (moleskin spandex). Basically I'm looking for a 2-sub setup that can give me the performance of 2 PB-2000's for less money.

Can anyone help me? I'm looking for someone to essentially tell me step-by-step what to build. Also, keep in mind that I am by no means an audiophile, but I do appreciate good bass that doesn't drown out all other sounds.
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post #2 of 128 Old 01-19-2014, 12:12 AM
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Amp - inuke 3000dsp ($375)to power 2
Marty subs (ported 18" Dayton or Si subs)($200 each)
Each sub is the equivalent to a pb13ultra.
So you are looking at $800+wood+glue+100 for the performance of 4 pb2000.
http://www.avsforum.com/t/1489541/large-ported-dayton-ho18s#post_23711347
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post #3 of 128 Old 01-19-2014, 04:13 AM
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Yeah what you do is come up with a design by copying to a degree (same size enclosure and tune) or one of your own in a thread like you’re doing. One or a few of us will sim it up for you and figure things out to a degree and you then hop at it at your own pace. You can post your questions as you move forward with rewarding us with your pics. Sometimes a guy starts off with asking what would be a good driver in a box no bigger than??? Some guys have no limit in enclosure size.

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post #4 of 128 Old 01-19-2014, 07:32 AM
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I dont think a PB13 Ultra can keep up with a Martysub...
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post #5 of 128 Old 01-19-2014, 07:43 AM
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Quote:
Originally Posted by eXa View Post

I dont think a PB13 Ultra can keep up with a Martysub...

Agreed. If you look at the measurements at data bass (sealed enclosure), it's significant enough. Pretty sure the differences will be even greater poreted
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post #6 of 128 Old 01-19-2014, 08:05 AM
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When you do compare, you need to be sure to add 6dB to Data's numbers on account they're 2m g p versus 1m g p in winisd though.

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post #7 of 128 Old 01-19-2014, 08:27 AM
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Originally Posted by steve nn View Post

When you do compare, you need to be sure to add 6dB to Data's numbers on account they're 2m g p versus 1m g p in winisd though.
Aren't they normalized to 1m? Measuring is done at 2m, because any closer and the result is corrupted by the presence of the box. Some places, notably Danley, measure at 10m/100w for more of a real world result. 10m/100w is the same as 1m/1w. It's a bit vague exactly what data-bass does, though there could be a footnote that I just haven't seen.

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post #8 of 128 Old 01-19-2014, 09:20 AM
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Yeah it's 6 dB Bill. A guy needs to add 9dB bassicly from the HSU site.

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post #9 of 128 Old 01-19-2014, 09:55 AM
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Originally Posted by steve nn View Post

Yeah it's 6 dB Bill. A guy needs to add 9dB bassicly from the HSU site.
Again, data-bass is confusing, SPL charts are vaguely labeled. For instance, the VTF 15H Basic Response chart shows a bit over 100dB, and that's certainly not 1w/1m, nor 1w/2m. Typical charts say right on them the conditions under which they were measured.

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post #10 of 128 Old 01-19-2014, 10:57 AM
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Yeah HSU is 3m. (9dB from other posts I've seen. I don't know the details but if you go 9dB you will see they pretty much match. 1m for winisd of course unless changed and 2m over at Data.

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post #11 of 128 Old 01-19-2014, 03:36 PM - Thread Starter
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Ok, before I start measuring my constraints, I guess I need to know all of my constraints.

1 - Is it preferred to orient the driver such that it faces the people?
2 - How close to my screen fabric can I place the driver or port?
3 - I have cabinet doors running across the bottom of my screen hiding my equipment. Can I place the subs down on the ground behind these cabinet doors or is it preferred to elevate them up to screen level?

Some constraints I've already placed on myself.....

A - I will only place the subs behind the false wall. No wiring in place for a sub anywhere else in the room.
B - I have a dedicated 20 amp circuit wired to my room for the subwoofer(s).
C - Has to fit behind the false wall, which is nominally 23.5" deep, but there are places that have more depth (e.g. behind any fabric components, or between studs).
D - If I'm going to do this myself, I'd like to keep the budget at $1000.
E - I really don't need any more performance than what would be attained from a couple PB-2000's. Remember, I'm not an audiophile.

So does anyone have an opinions on 1-3? I'm excited to take this on.
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post #12 of 128 Old 01-19-2014, 03:48 PM
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"It's a bit vague exactly what data-bass does, though there could be a footnote that I just haven't seen."

i'm pretty sure that all the measurements are at 2m except where it is specifically noted as 1m or 10m.

the sweeps correlate with winisd predictions (which as you know is 2pi 1m) with 6db added to the db numbers for the low bass. the upper bass is a little more tricky because some of the larger cabs provide a little bit of their own boundary gain.
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post #13 of 128 Old 01-19-2014, 03:57 PM
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"1 - Is it preferred to orient the driver such that it faces the people?"

doesn't really matter. lots of good subs fire sideways or up/down.

" 2 - How close to my screen fabric can I place the driver or port?"

that is a great unknown and depends of course on the port velocity of the sub. best would be to just port it up or sideways so it isn't blowing on the screen in the first place.

" 3 - I have cabinet doors running across the bottom of my screen hiding my equipment. Can I place the subs down on the ground behind these cabinet doors or is it preferred to elevate them up to screen level?"

they don't have to be up at screen level unless you are going for the 1/4 distance spacing idea.

Some constraints I've already placed on myself.....

A - I will only place the subs behind the false wall. No wiring in place for a sub anywhere else in the room.

suggest 1/4 distance array with at least 4 units then.

B - I have a dedicated 20 amp circuit wired to my room for the subwoofer(s).

that should be fine.

C - Has to fit behind the false wall, which is nominally 23.5" deep, but there are places that have more depth (e.g. behind any fabric components, or between studs).

that should be fine.

D - If I'm going to do this myself, I'd like to keep the budget at $1000.

a minimum of two martys as described above would be in that budget and pound pretty hard. four drivers would give a little more flexibility for placement and mode killing.

E - I really don't need any more performance than what would be attained from a couple PB-2000's. Remember, I'm not an audiophile.

who cares what you need? :-)

"I'm excited to take this on."

yahoo!

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post #14 of 128 Old 01-19-2014, 04:05 PM
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Quote:
who cares what you need? :-)

"I'm excited to take this on."

yahoo!

Thank God somebody finally said that. It reminds me of a guy I was helping out yesterday. Like we're gaining something or it’s such a XXXX privilege! rolleyes.gif

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post #15 of 128 Old 01-19-2014, 04:08 PM
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Quote:
Originally Posted by LTD02 View Post

"It's a bit vague exactly what data-bass does, though there could be a footnote that I just haven't seen."
i'm pretty sure that all the measurements are at 2m except where it is specifically noted as 1m or 10m.
I'm not sure. Look at the Basic Response chart here:
http://www.data-bass.com/data?page=system&id=100&mset=109

What is it supposed to represent? 1m/1w? Halfspace? Nothing I can find on that page says, and IMO one shouldn't have to search the entire website to figure it out. And where taking measurements at more than 2m is SOP it's also SOP to normalize the result to 1m/1w or 1m/2.83v. They may be doing that, they may not. I may be old and not as sharp as I once was, but I haven't totally lost touch yet, and I can't find a succinct explanation.

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post #16 of 128 Old 01-19-2014, 04:14 PM - Thread Starter
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What's a 1/4 array? I'm assuming if I just have 2 subs that I'd place them 1/4 of the way from each side wall at the same height, but what happens if I have 4 subs?
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post #17 of 128 Old 01-19-2014, 05:21 PM - Thread Starter
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Quote:
Originally Posted by steve nn View Post

Thank God somebody finally said that. It reminds me of a guy I was helping out yesterday. Like we're gaining something or it’s such a XXXX privilege! rolleyes.gif
I'm not sure I'm getting your meaning?
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post #18 of 128 Old 01-19-2014, 05:43 PM
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Quote:
Originally Posted by steve nn View Post

Thank God somebody finally said that. It reminds me of a guy I was helping out yesterday. Like we're gaining something or it’s such a XXXX privilege! rolleyes.gif
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Originally Posted by Crash11 View Post

I'm not sure I'm getting your meaning?

I think someone was taking Mr. Steve's help for granted, and was being a bit of a poo-poo head about it. wink.gif

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post #19 of 128 Old 01-19-2014, 07:14 PM
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I think someone was taking Mr. Steve's help for granted, and was being a bit of a poo-poo head about it. wink.gif

I’m sure it was some kid (maybe not) that didn’t know the meaning of common curtsies that I better not catch my kids (even though they’re grown) lacking in. Imo It’s the principle of the matter albeit little stevie needs to take a break now and then. smile.gif

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post #20 of 128 Old 01-19-2014, 10:13 PM
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What's a 1/4 array? I'm assuming if I just have 2 subs that I'd place them 1/4 of the way from each side wall at the same height, but what happens if I have 4 subs?

Since you want all four up front (that would be quite the rig) you would divide the distance of the two walls by 1/4 and place in a line accordingly. Another option if you were to build 4, and since they’re going to be hid, is to go the sono route. Building 4 of the Marty's would be quite a chore, building 4 sono’s would be much easier. It would basically be the same sub performance wise. Just a thought..

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post #21 of 128 Old 01-20-2014, 10:29 AM
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You can build a tht from bill as a coffee table. It's also pretty wicked for less money but much more difficult. But 2 Si and a 3000dsp has the most value.
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post #22 of 128 Old 01-20-2014, 11:48 AM
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What's a 1/4 array? ...
Well since an array is 2 or more elements sharing a passband.
a 1/4 array does not exist - except as a misunderstanding smile.gif

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post #23 of 128 Old 01-20-2014, 12:06 PM
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4 subs. 1 sub 1/4 in from the left wall and 1/4 up from the floor. One sub 1/4 in from the right wall and 1/4 up from the floor. One sub 1/4 in from the left wall and 1/4 down from the ceiling. One sub 1/4 in from the right wall and 1/4 down from the ceiling. I'm sure LTD will post a pic when he checks back in.
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post #24 of 128 Old 01-20-2014, 01:43 PM
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Ah...
I tend to start with fractions like 1/3, 1/5 etc
But whatever gets the task accomplished

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post #25 of 128 Old 01-20-2014, 03:05 PM - Thread Starter
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Quote:
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You can build a tht from bill as a coffee table. It's also pretty wicked for less money but much more difficult. But 2 Si and a 3000dsp has the most value.
?????

What's an SI?
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post #26 of 128 Old 01-20-2014, 03:46 PM
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Stereo Integrity HT 18" Subwoofer

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post #27 of 128 Old 01-20-2014, 06:27 PM - Thread Starter
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Ok, let's try to narrow down this design some. Here's a shot of my screenwall:



My plan for now is to just build 2 subs. I know more is always better, but this is my first attempt at making a speaker so let's just take baby steps. With that in mind, I have the ability to place them both at 1/4 (44.5") from each side wall. That's about 14" from the edges of the velvet screen border. This is also ideal for depth behind my false wall. I have 27.5" of room between the back wall and the screen material. Also, I want to keep the boxes elevated above the cabinet door to leave room for storage and more equipment. So that leaves about 50" of height to work with. So in this position, will a Martysub work with the driver being at the long end? Can I stand them up vertical and face the driver and port up? Also, keep in mind that the panel I built above the screen is not acoustically transparent. It's a solid 1x10 piece of pine wrapped in fabric. How would you guys orient a couple subs with this setup?

Another issue.....where to place the amp. I originally planned to build an IB so I actually wired my 20 amp plug behind the theater. My plan was to have all of the wiring and power in my utility room behind the theater, and the only run going through the wall was going to be the pre-out from the receiver. Check out these pictures:

Narrow angle shot of the back of my theater:


Closer shot showing the lone outlet for my subwoofer in the bottom right:


Close up of my open box for passing cables through:


I was thinking about placing the amp back in this room because I saw a few complaints about fan noise. I'd have to run the pre-out line through my "hole" as well as the speaker wire runs. Is this a bad idea?
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post #28 of 128 Old 01-20-2014, 06:43 PM
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^^ nice room..... Good job

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post #29 of 128 Old 01-20-2014, 07:01 PM - Thread Starter
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^^ nice room..... Good job
Thank you.
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post #30 of 128 Old 01-23-2014, 08:12 AM - Thread Starter
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