JimP
Registered: 07/03/07
Posts: 115
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| Posted 10/08/08 at 01:36 PM | Reply with quote #1 |
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I guess this is more or less an open question to Mark.
I hear that you've designed all three subs (Sasquach, BMF-1 and the big one for AV123) and that each has their own design goals.
Can you elaborate how they're different.
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Mark_Seaton
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Registered: 05/29/07
Posts: 1,490
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| Posted 10/08/08 at 03:14 PM | Reply with quote #2 |
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Quote: Originally Posted by JimP
I guess this is more or less an open question to Mark.
I hear that you've designed all three subs (Sasquach, BMF-1 and the big one for AV123) and that each has their own design goals.
Can you elaborate how they're different.
Hi Jim,
I'm not sure of what subwoofer you mean by "the big one for AV123", as the Sasquatch is intended for TCA, and the BMF for AV123. If you look at TCA's website, you will find plenty of discussion of the different design goals. The BMF is a different design implementation which as big as it is, is still smaller than the Sasquatch. The Sasquatch is my take on a large vented design using a very cool driver in a BIG box, although subs like the Conquest are still larger. The BMF should have a bit more power down low, with the benefits of PRs vs. ports, as well as the advantages of the bandpass design.
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TheRick
Registered: 06/20/07
Posts: 522
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| Posted 10/08/08 at 03:52 PM | Reply with quote #3 |
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Mark,
Forgive my very NOVICE mindset here. But, I was just reading a bit last night about bandpass designs in the Intro to speaker design book, and I was wondering how you get that deep bass extention with that design? What I'm getting at is that the book said that bandpass designs, in general, have a lower pass and high pass filter built into them. The sealed box along with a vented box approach (where the driver is enclosed) causes a rolloff on both the upper and lower ends of 12db/octave (unless you go to a 5th or 6th order design). It seems, from reading, that sealed and vented are the ways to go, and I couldn't wrap my head around where a bandpass design would really fit in having a built in low end rolloff like that. I would think the in-room deep (low) bass would be lost in that design. Granted, the BMF is a PR design which I haven't gotten too yet....LOL!
Don't beat on me too much for being in error.....LOL! Assume that I'm on the right path in my trying to learn about speakers here.... 
Rick
You can try to get to the page I am talking about by searching for "bandpass" (page 16) at amazon....
http://www.amazon.com/gp/sitbv3/reader?asin=096637732X&pageID=S00O&checkSum=EoQ+1QlKt4QgMTivuusGeWOkQzMV2WLFWxKfR G9qcbc=
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Mark_Seaton
Moderator
Registered: 05/29/07
Posts: 1,490
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| Posted 10/08/08 at 04:41 PM | Reply with quote #4 |
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Quote: Originally Posted by TheRickMark,
Forgive my very NOVICE mindset here. But, I was just reading a bit last night about bandpass designs in the Intro to speaker design book, and I was wondering how you get that deep bass extention with that design? What I'm getting at is that the book said that bandpass designs, in general, have a lower pass and high pass filter built into them. The sealed box along with a vented box approach (where the driver is enclosed) causes a rolloff on both the upper and lower ends of 12db/octave (unless you go to a 5th or 6th order design). It seems, from reading, that sealed and vented are the ways to go, and I couldn't wrap my head around where a bandpass design would really fit in having a built in low end rolloff like that. I would think the in-room deep (low) bass would be lost in that design. Granted, the BMF is a PR design which I haven't gotten too yet....LOL!
Don't beat on me too much for being in error.....LOL! Assume that I'm on the right path in my trying to learn about speakers here....
Rick
You can try to get to the page I am talking about by searching for "bandpass" (page 16) at amazon.... http://www.amazon.com/gp/sitbv3/reader?asin=096637732X&pageID=S00O&checkSum=EoQ+1QlKt4QgMTivuusGeWOkQzMV2WLFWxKfR G9qcbc=
Hi Rick,
I think you confused where a few of the "filters" are coming from. High pass in a bandpass comes from the low frequency alignment and is very similar to what you would get from any similar design such as a sealed or reflex design. Re-read pages 30-33 with particular attention to the strengths and pitfalls listed on page 31, as the last paragraph on that page largely sums up what added variables you have to manipulate. Getting useful results from those variables is the tricky part. 
I've built bandpass designs that extend to 1kHz and others that start rolling off above 40Hz. It all depends on the execution. I've also worked out bandpass designs which can span more than 3 octaves. There are more factors at play than discussed in the overview given in John Murphy's book, and it is those nuances of the design and operation which play a big factor in getting good sound from them.
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Mark Seaton
Seaton Sound, Inc.
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JimP
Registered: 07/03/07
Posts: 115
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| Posted 10/09/08 at 06:09 AM | Reply with quote #5 |
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Mark
Now that I'm more awake, (ought to not post at 1:30a.m.) the three subs in question are the Sasquach for Craig, BMF-1 for AV123, and the SubMersive under your own brand.
You have answered my initial question, though. Any news on the BMF-1?
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Mark_Seaton
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Registered: 05/29/07
Posts: 1,490
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| Posted 10/09/08 at 10:25 AM | Reply with quote #6 |
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Quote: Originally Posted by JimPMark Now that I'm more awake, (ought to not post at 1:30a.m.) the three subs in question are the Sasquach for Craig, BMF-1 for AV123, and the SubMersive under your own brand.
You have answered my initial question, though. Any news on the BMF-1?
No problem on the confusion Jim. A more interesting comparison of my own to these large monsters will be the Terraform and Terraform XL(dual driver) which will be come more formalized and more readily available in the next month or two (a few are in construction and a couple more in the que). The Terraform is tuned much lower (11-13Hz) and a bit larger than either. I'm also considering a built-to-order Terraform HO which would be intended to fill very large rooms to very high, clean levels above ~20Hz, but that's still in the "possible" realm and dependent on some other factors.
Currently the UFW-12 and MFW-15 manual are at the top of my to-do list for AV123, so no significant news on the BMF at this very moment.
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fugueness
Registered: 06/02/08
Posts: 137
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| Posted 10/11/08 at 05:07 PM | Reply with quote #7 |
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Quote: Originally Posted by Mark_Seaton
I'm also considering a built-to-order Terraform HO which would be intended to fill very large rooms to very high, clean levels above ~20Hz, but that's still in the "possible" realm and dependent on some other factors.
Will the Terraform HO be akin to the JTR Growler in terms of adding more mid-bass punch?
I'm looking forward to hearing a pair of Terraform XL's
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Mark_Seaton
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Registered: 05/29/07
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| Posted 10/12/08 at 01:27 PM | Reply with quote #8 |
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Quote: Originally Posted by fuguenessQuote: Originally Posted by Mark_Seaton
I'm also considering a built-to-order Terraform HO which would be intended to fill very large rooms to very high, clean levels above ~20Hz, but that's still in the "possible" realm and dependent on some other factors.
Will the Terraform HO be akin to the JTR Growler in terms of adding more mid-bass punch? I'm looking forward to hearing a pair of Terraform XL's
Hi fugueness,
The Growler has highly impressive power above 40-45Hz, where 1kW can deliver clean levels around 130dB @ 1m. A pair of SubMersives can actually match or exceed this capability while still extending down low. The Terraform XL will have the upper bass power of the SubMersive, with about 60-80% more power down low than the standard Terraform, remembering these are tuned to ~12Hz with useful response to ~10Hz.
The Terraform HO is just a concept at the moment, and subject to change, but what I'm considering is a good 3-5dB more power in the upper octave than a standard Terraform, with 4-6dB more capability in the 18-35Hz range (that's almost 2x the capability). The trade off is of course in extension, but with benefits of a smaller package than the Terraform. How much smaller depends on some choices of size vs. output, where a trade of 0.5-2dB can allow for a box that's 2-3 cu.ft. smaller than the larger of the two options I'm looking at.
The purpose here is for large rooms and those cases where greater output/intensity is needed more than VLF extension, and the cost or size of lower extension isn't as practical. To put some tangible numbers on this, I'm talking about output capabilities of more than 120dB@1m above 30-35Hz (=>116dB@2m gp), and 118-120dB@ 1m at 25Hz with low distortion, compression, and very good sound quality. In many rooms the standard and XL versions would be my choice, but there are cases where you simply need more capability for the desired listening levels, and I can implement this design without adding to parts I'll already have on hand for my currently planned subwoofers, other than the enclosure.
I'm guessing that was clear as mud. 
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mfine
Registered: 07/31/07
Posts: 534
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| Posted 10/12/08 at 02:35 PM | Reply with quote #9 |
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Mark,
What are the target rooms and applications for the various products? I think that might help people understand better.
For example (feel free to edit to be correct)
The SubMersive does well in small to medium sized dedicated theaters that are generally well enclosed. The natural rolloff matches with room gain in such rooms to give excellect low end extension.
The Terraform is for larger or more open theaters and has more output it the 15-30 range since such rooms have less gain.
The HO is for night clubs and other professional installs in much larger spaces where the extension is less important than the output levels above 30-35 hz.
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Mark_Seaton
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| Posted 10/13/08 at 06:33 PM | Reply with quote #10 |
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Hi mfine,
Good questions and points worthy of an appropriate response. Unfortunately I only recently had my internet connection come back on line after being out most of the day. I'll post some thoughts on this later tonight and/or tomorrow, as well as comment on some other threads here. More later...
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Mark Seaton
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fugueness
Registered: 06/02/08
Posts: 137
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| Posted 10/14/08 at 02:38 PM | Reply with quote #11 |
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Quote: Originally Posted by Mark_Seaton
The Terraform HO is just a concept at the moment, and subject to change, but what I'm considering is a good 3-5dB more power in the upper octave than a standard Terraform, with 4-6dB more capability in the 18-35Hz range (that's almost 2x the capability). The trade off is of course in extension, but with benefits of a smaller package than the Terraform. How much smaller depends on some choices of size vs. output, where a trade of 0.5-2dB can allow for a box that's 2-3 cu.ft. smaller than the larger of the two options I'm looking at.
Sounds very interesting!
How might a Terraform HO perform in concert with a Terraform XL? (compared to dual Terraform XL's)
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MikeDuke
Registered: 06/06/07
Posts: 1,013
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| Posted 10/14/08 at 05:12 PM | Reply with quote #12 |
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With the SubMersive1, Terraform, Terraform XL, Terraform HO, SubMersive2, Catalyst and the Spark and possibly a Spark HO, you will have quite the arsonal to choose from. Plus, who knows what else is going to come down the pike. I know that customers come first, but I really hope that you can get the website up and running so we can see some pictures and get some more info.
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Mark_Seaton
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| Posted 10/15/08 at 03:46 PM | Reply with quote #13 |
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Quote: Originally Posted by fuguenessQuote: Originally Posted by Mark_Seaton
The Terraform HO is just a concept at the moment, and subject to change, but what I'm considering is a good 3-5dB more power in the upper octave than a standard Terraform, with 4-6dB more capability in the 18-35Hz range (that's almost 2x the capability). The trade off is of course in extension, but with benefits of a smaller package than the Terraform. How much smaller depends on some choices of size vs. output, where a trade of 0.5-2dB can allow for a box that's 2-3 cu.ft. smaller than the larger of the two options I'm looking at.
Sounds very interesting! How might a Terraform HO perform in concert with a Terraform XL? (compared to dual Terraform XL's)
With any differing model subwoofers I prefer to not try and pair 2 reflex designs with significantly different low frequency tunings. The only exception being when you go to a 2-way bass solution, where the two are crossed over rather than both covering the same range.
I don't much see a justification for a Terraform HO to mate with a standard Terraform or XL model when you could instead add a second of either, especially when the Terraform HO should be equal or slightly greater than the cost of a Terraform, which I am estimating at $2495 + shipping. Of course the Terraform HO is still just a concept under consideration, not yet a reality.
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Mark Seaton
Seaton Sound, Inc.
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