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post #1 of 24 Old 01-03-2012, 12:21 AM - Thread Starter
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Let me start by saying that i know pretty much nothing about speakers, amps, or even sound basics, much less diy speaker construction. But i've been reading so many threads about TH's over the last month or so, that i definitely want to give it a shot.

I bought BF's THT LP plans a few weeks ago, but now after reading so many other build threads, i'm thinking the THT might be overkill for my home theater room(approx 20' X 20' and only 7' ceiling). I have enough space for it, but my house is about 60 yrs old and my theater room is in the basement, and i don't want my house coming down on top of us or anything like that.

A few builds that really caught my attention are: Exodus Anarchy 6.5" 25hz Tapped Horn by radman12 and lilmike
Or the even more budget friendly: MCM 55-2421 8" 28hz Tapped Horn by tsloms

Whichever build i choose to do, i don't want to mess it up. I'm just not sure if i should stick to BF's THT since it comes with pretty detailed, thorough instructions, or if i'd be just as good trying one of the builds i just listed above?

Also, the MCM 8" TH would be the best for me financially, but i don't want have any perspective as to how good it would sound. Particularly, how much better it would sound than my current Sony HTiB 10" subwoofer. I'm hoping someone can help answer some of these questions i have and/or help guide me in the right direction so i can pull the trigger on whatever i need to order, because i really am anxious to get started!
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post #2 of 24 Old 01-03-2012, 07:04 AM
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Quote:
Originally Posted by staindrocks View Post

Let me start by saying that i know pretty much nothing about speakers, amps, or even sound basics, much less diy speaker construction. But i've been reading so many threads about TH's over the last month or so, that i definitely want to give it a shot.

I bought BF's THT LP plans a few weeks ago, but now after reading so many other build threads, i'm thinking the THT might be overkill for my home theater room(approx 20' X 20' and only 7' ceiling). I have enough space for it, but my house is about 60 yrs old and my theater room is in the basement, and i don't want my house coming down on top of us or anything like that.

A few builds that really caught my attention are: Exodus Anarchy 6.5" 25hz Tapped Horn by radman12 and lilmike
Or the even more budget friendly: MCM 55-2421 8" 28hz Tapped Horn by tsloms

Whichever build i choose to do, i don't want to mess it up. I'm just not sure if i should stick to BF's THT since it comes with pretty detailed, thorough instructions, or if i'd be just as good trying one of the builds i just listed above?

Also, the MCM 8" TH would be the best for me financially, but i don't want have any perspective as to how good it would sound. Particularly, how much better it would sound than my current Sony HTiB 10" subwoofer. I'm hoping someone can help answer some of these questions i have and/or help guide me in the right direction so i can pull the trigger on whatever i need to order, because i really am anxious to get started!

IMO, the THT is the minimum I'd consider running in a room as big as yours.

I don't think you'll have much to worry about; FWIW my house is almost 30 years old and I'm fixin to run 3 of the IST Xmass 18 inchers from 2kw RMS in a HT room that's roughly the same volume as yours, except open to more of the basement and to the main floor (open staircase, no door).
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post #3 of 24 Old 01-03-2012, 08:47 AM
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as a test, go outside and push on one side of your house really hard. if it holds, then you will be ok with the tht. :-)

Listen. It's All Good.
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post #4 of 24 Old 01-03-2012, 11:05 AM
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Originally Posted by ltd02 View Post

as a test, go outside and push on one side of your house really hard. If it holds, then you will be ok with the tht. :-)

lol
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post #5 of 24 Old 01-03-2012, 02:31 PM - Thread Starter
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Originally Posted by LTD02 View Post

as a test, go outside and push on one side of your house really hard. if it holds, then you will be ok with the tht. :-)

That's pretty darn funny!

If i go with the THT, which amp should i get to go with it. I'm thinking the Bash 300w, unless there is a much cheaper alternative. And what difference will it make whether i get the Dayton Audio 15" DCS385-4 or the Dayton Audio RSS390HF-4 15", besides the latter being $13 more expensive?

Also, since i have to order the driver and the amp from PE, what else do i need for the build that i should go ahead and include in my order from PE?
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post #6 of 24 Old 01-03-2012, 03:28 PM
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Quote:
Originally Posted by staindrocks View Post

And what difference will it make whether i get the Dayton Audio 15" DCS385-4 or the Dayton Audio RSS390HF-4 15", besides the latter being $13 more expensive?

Here's a thread on the subject at the BFM forum (ignore if that's your thread under a different name ).

http://billfitzmaurice.info/forum/vi...hp?f=5&t=16815

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Originally Posted by staindrocks View Post

Also, since i have to order the driver and the amp from PE, what else do i need for the build that i should go ahead and include in my order from PE?

Speaker gasket tape; driver mounting kit (screws and t nuts); binding post.

You will also need 2-3 tubes of PL adhesive, some countersunk screws, sandpaper, primer, paint; and tools: circular saw / table saw, jigsaw, router, drill, a belt or orbital sander).
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post #7 of 24 Old 01-03-2012, 03:44 PM - Thread Starter
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Thanks for the link, Brad. As far as the binding post is concerned, is there any particular type or brand that seems to be favored?
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post #8 of 24 Old 01-03-2012, 03:55 PM
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since you don't need much power for the amp with a tht or the lilmike f-20 (free plans) and with the 300 watt amp on sale, that should be fine.

Listen. It's All Good.
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post #9 of 24 Old 01-03-2012, 04:13 PM - Thread Starter
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Thanks for confirming that for me, LTD02. How many watts does the THT actually use at it's max? I've read about high pass/low pass filters and i guess some amps have them built in, so does the Bash have such a thing. If so, it's not set at like 30hz or something where it could limit what i get out of my THT on the low end, is it?
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post #10 of 24 Old 01-03-2012, 04:22 PM
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"If so, it's not set at like 30hz or something where it could limit what i get out of my THT on the low end, is it?"

no. it would be in the upper teens if it has one.

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post #11 of 24 Old 01-03-2012, 04:25 PM
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"How many watts does the THT actually use at it's max?"

that is a tough question to answer because at some points it can take 300 watts at other points the driver runs out of excursion, but you really only need 100 watts or so to hit reference spl 115db in room.

whatever you end up doing, make sure that you follow the plans.

use lots of pl in order to minimize air leaks. air leaks are one place folks mess up, but there is no need to.

Listen. It's All Good.
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post #12 of 24 Old 01-03-2012, 06:55 PM
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build a mfw-15 clone

FSChris
ASROCK H67 GE / HT
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Zaph 2.5MM TT'S DIY

Emotiva XPA3

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post #13 of 24 Old 01-04-2012, 12:24 AM - Thread Starter
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It looks like PE is out of stock on the sub until the 10th of this month, so i'm trying to decide whether to order everything now while the Bash 300w amp is still on sale, but then i'd most likely get two separate shipments.

How do their prices fluctuate there? Do they change often, and if so, do they come down as well as go up? I'd just like to get some idea if where the sub and amp are priced at now are at their best prices, or if i wait and keep checking their site could i get a better deal(kinda like newegg or amazon)?
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post #14 of 24 Old 01-05-2012, 11:31 AM
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You are better off ordering the 300w BASH now because its price is so low. If you wish you can order the subwoofer speaker at the same time. They sometimes ship to the pre-order individuals a few days in advance of when they state the the out-of-stock item will be back in stock.
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post #15 of 24 Old 01-06-2012, 12:42 AM - Thread Starter
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Thanks for the reply, wwinkler. I guess i'll go ahead and get my order in then!
So here's everything i've put in my cart(let me know if i forgot something):
  • Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm
  • Bash 300W Digital Subwoofer Amplifier
  • Cast Frame #10-32 Speaker Mounting Kit
  • #10-32 Hurricane Nuts 50 Pcs.
  • Speaker Gasketing Tape 1/8" x 1/2" x 50 ft. Roll

Oh yeah, and then i need binding posts. Can someone help me out with recommending a set of these... i really have no idea which ones to pick because i don't know what the difference between them is, and they have about 23 different choices to pick from.
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post #16 of 24 Old 01-06-2012, 07:29 AM
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Well, having used these twice now, I really like them. I can't say they are the best because I haven't used all of their products yet. They are very sturdy and also high quality. They accept really large gauges of wire. Although if you are using a BASH plate amp, why do you need them?

http://www.parts-express.com/pe/show...umber=091-1245

Also if it is in your budget I'd spring for the BASH 500W amp myself, with that beefy driver.
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post #17 of 24 Old 01-06-2012, 03:34 PM - Thread Starter
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Originally Posted by djkest View Post

Although if you are using a BASH plate amp, why do you need them?

Like i said, i'm about as noob as a noob can be when it comes to speakers, amps, etc... but I thought i read where people recommend building a box for the plate amp to keep it outside the speaker enclosure and near the AVR. So i figured that i'd need the binding posts for the THT's connection to the amp, but please let me know if i'm wrong.
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post #18 of 24 Old 01-08-2012, 09:09 PM - Thread Starter
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I just got offered a deal on a O-Audio 500w Bash plate amp, so could someone tell me whether this would be a good choice to use with the THT LP? From what i've read it seems to be a better amp w/EQ than the PE 300w Bash, but i want to make sure it doesn't limit my THT in any way that the PE Bash does not. Is there anything i'd be giving up or issues i'd need to be aware of if i chose the O-Audio 500w Bash to pair with the THT instead of the PE 300w Bash?

I'd like to go as low and loud as possible, without having to worry about endangering my driver... just in case that has any bearing on which one would be the better amp to get. I know that the PE 300w Bash comes highly recommended, but if i can get the O-Audio 500w Bash for around the same price, which would be the better choice?
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post #19 of 24 Old 01-08-2012, 10:36 PM
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Quote:
Originally Posted by staindrocks View Post

I just got offered a deal on a O-Audio 500w Bash plate amp, so could someone tell me whether this would be a good choice to use with the THT LP? From what i've read it seems to be a better amp w/EQ than the PE 300w Bash, but i want to make sure it doesn't limit my THT in any way that the PE Bash does not. Is there anything i'd be giving up or issues i'd need to be aware of if i chose the O-Audio 500w Bash to pair with the THT instead of the PE 300w Bash?

I'd like to go as low and loud as possible, without having to worry about endangering my driver... just in case that has any bearing on which one would be the better amp to get. I know that the PE 300w Bash comes highly recommended, but if i can get the O-Audio 500w Bash for around the same price, which would be the better choice?

The O audio amplifier will work perfectly.
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post #20 of 24 Old 01-09-2012, 02:36 PM - Thread Starter
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The O-Audio Bash 500 can be used for ported subs in certain circumstances. It has 4 selectable subsonic filters with varying amounts of boost. The 25 hz SSF has no boost, the 20 hz SSF has 4 db of boost, the 16 hz SSF has 6 db of boost and the 12 hz SSF has 8 db of boost. ( O-Audio will not state the amounts of boost, the amounts are estimated from looking at their published graph in the manual.) The amp also has a EQ that is cut only, with an effective frequency range of 20 hz to 80 hz. The EQ can be used to defeat the boost for the 20 hz SSF, but not for the 16 hz and 12 hz SSF's. If you have a ported sub that needs a SSF at 20 hz with or without boost, the O-Audio amp will work.

Quote:


The OAudio 500W amp choice is a poor one for these ported designs. The subsonic filter is such
that it will cause a peak in the response for anything other than the 25Hz Subsonic filter
setting.

These are a few of the posts i've read about lowend boosts, which i don't know enough about to know how this might affect the THT's performance? Does anyone know the answer, or can you help explain what it means?
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post #21 of 24 Old 01-09-2012, 05:24 PM
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I use 2 THTs with an OAudio 500W amp for each, set at the 16Hz subsonic filter position. Gives about 5 more Hz extension for me. For the most output, use the 25Hz or 20Hz position.

The 25Hz filter does not add any boost, or very little. If you will be blasting music, or need insane levels, this is it. You can feed the THT all 40V (~400W) the amp is capable of at this setting, and get 125dB+ at 1m (over 130dB with two) if corner loaded. BTW - This is LOUD. You will break stuff in the house, and knock paintings off walls and such. Radman broke a vase, IIRC....

The 20Hz filter adds more boost, and still gives you great output. You should not use more than ~25V, though, as the driver in the THT will start reaching its excursion limits. In my model, an RSS390HF in a THT reaches max excursion around 20Hz when placed in a room corner, and drops below that.

The 16Hz filter is the one I use. I do not need full output, as I listen to movies at -10dB. I get a few more clean dB down low with it. My THTs never see more than 13-15V each, unless I am just running tests. 105-108dB at 20Hz at the LP is enough to move stuff, a lot. My 1/2" MDF screen (attached with a french cleat) rattles on the front wall, and the floor above moves enough to shake the ceiling mounted projector at this level (-10dB). If I were to go to full reference, I'd start cracking drywall.

The 12Hz filter can give you more super low, but it will be distorted. You are an octave out of the THT passband at that point, and the amp will run out if juice and clip in very strong ULF movies, like The Incredible Hulk, Battle:LA and others....

JSS
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post #22 of 24 Old 01-09-2012, 09:36 PM - Thread Starter
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Thanks a lot for that thorough explanation, maxmercy!

I'm going to be using the RSS390H in my THT, too. The 16Hz filter sounds pretty good to me. In the 20Hz filter example, you said not to use more than ~25V, as the driver will start reaching its excursion limits... what about when set at the 16Hz subsonic filter position, what is the limit one shouldn't go beyond in this setting? I know you said you never feed your THTs more than 13-15V each, which i probably won't either, but it would be nice to know the danger point nevertheless.
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post #23 of 24 Old 01-10-2012, 03:13 AM
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Same, around 25V. Things will begin to sound different around 20V, unless youhave the 25Hz setting engaged, and then you can go all the way to 40V (I'd stop at 30V, personally).

Make sure you have no air leaks.

If you have not bought the THT plans, you could consider the F-20. Plans are free, and although a bit bigger, it has a nice form factor. The THT and F20 are more similar than different, but with F20, the driver stays in a side firing configuration when stood up on end, unlike THT. This is important with the RSS driver. I have my THTs on their sides due to this. The RSS driver has more distortion when up/down firing.

JSS
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post #24 of 24 Old 01-11-2012, 12:04 PM - Thread Starter
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Quote:
Originally Posted by maxmercy View Post

If you have not bought the THT plans, you could consider the F-20. Plans are free, and although a bit bigger, it has a nice form factor. The THT and F20 are more similar than different, but with F20, the driver stays in a side firing configuration when stood up on end, unlike THT. This is important with the RSS driver. I have my THTs on their sides due to this. The RSS driver has more distortion when up/down firing.

JSS

I have already bought the THT LP plans, with the intention of standing it up in the corner of the room, although laying it down wouldn't be a problem either. But it would be nice to have the flexibility to do either just to future proof my HT room layout.

A big reason why i bought the THT LP plans instead of going with a free alternative is because i've never built any kind of speaker/subwoofer before, and i read that Bill's plans were a very detailed, step by step set of instructions that could guide anyone through the build from start to finish. But now that i checked out the F-20 build thread, it doesn't seem like it would be very hard to build.

So now i'm not sure which one i should build? Pretty much, you're saying if i ever want to stand it up on end as a tower sub, then i should build the F-20?

One other thing i was wondering about... would it be possible to make one of the sides of the enclosure built out of a clear material rather than wood? Has anyone already tried this? If so, what kind of see-thru material, and at what thickness, would it take to hold up to the forces generated by this sub? I think the internal designs look so cool, that it would be awesome to run some sort of leds w/see-thru side so you could show off all of it's internal guts and how it works. But i wouldn't want to do it if it affected the build quality or sound in any way. So i'm just wondering if it's possible?
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