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Tham15 confusion
Tham15 confusion
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Old 2nd November 2017, 07:14 PM   #1
REIER is offline REIER
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Default Tham15 confusion

Hi all of you amazing nerds!

Some years ago, I had a dream! I wanted to host my own small cozy rave festival out in the woods. Last summer, I decided to make it real. Needless to say, there was this issue of sound. Being in the woods, limitations such as power consumption and portability presented themselves. I spent most of the summer learning about 12v systems and basic speaker theory, and when party time was on, there was almost no time left to build speakers. I made two semipro halfinators (hp10w + PHT407N) from the Boominator design,. They did a really good job for their size and all of the 15 people were raving.

Next summer it is time to put some more sound pressure and bass in to nature. We are aiming at 50 people+ this year, so it is just natural to do the level up.
I have been looking at portable sub designs that I can pair up with the Boominator satelites, and for now the Tham15 seems to be the go to.

So here is my problem: The recommended drivers for Tham15 is the B&C 15TBX100. As much as I would have loved to have these guys, they are too much of a burden for my wallet, and I cant seem to find them in Norway anyway.

The other day, I read some posts in this and other forums from a skilled guy named magicjohansson, and he had successfully accomplished the mission of building these cabs with cheaper drivers that sims well.
martinson tham 15 - Speakerplans.com Forums - Page 3

He used the cheaper 15ps100, and this made my day. I was about to cash out, but my heart rate stopped me when I got confused about some uncertainties with TS parameters. The woofers I was about to buy showed these parameters: B&C 15PS100 - 8Ohm, 218,96 €

for some reason I checked with B&C web site, and my world fell apart when i discovered that the TS numbers were different:
B&C Speakers

Immediately I wondered if B&C changed specs for these drivers between 2012 and now, and if this error was significant for my life. Will these differences in TS parameters make better or worse end result, and what version of the 15ps100 will be the right one for me? And if someone knows about even better suited drivers for the same price, I would throw baskets of gratefulness in their direction.

Now I'm hoping that someone out there will read my story and reach out to me, helping me understand what is going on, and telling me what my next step should be.
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Old 2nd November 2017, 09:13 PM   #2
Xoc1 is offline Xoc1  United Kingdom
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The Tham is a very compact design. It trades efficiency for size.
If you want more efficency you will need to go bigger.
I would say you should look at the SS15 design, as this will give you more volume with limited amounts of power. It can be built as a very lightweight cabinet.
Hopefully that would be closer to your design goals.
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Old 2nd November 2017, 09:29 PM   #3
weltersys is offline weltersys  United States
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Quote:
Originally Posted by REIER View Post
Immediately I wondered if B&C changed specs for these drivers between 2012 and now, and if this error was significant for my life. Will these differences in TS parameters make better or worse end result, and what version of the 15ps100 will be the right one for me?
You may not have a choice between finding new versions of the 15PS100, but the differences in the TS parameters between the two are not going to make much difference in response.
If you can get the 4 ohm version you will probably be able to deliver more power to it, especially if you are using 12V amps.

Rave On,
Art
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Old 2nd November 2017, 10:00 PM   #4
Brian Steele is offline Brian Steele  Grenada
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Quote:
Originally Posted by REIER View Post
Will these differences in TS parameters make better or worse end result,
Should be easy to check in Hornresp. Find the original sim for the THAM15, then replace the driver specs in the sim with the ones posted on the B&C website.

The THAM design is a decent exercise in compromise - "small" box, good extension, good efficiency. It's the choice to make it smaller that actually led to that big dip in the response between 100 and 200 Hz. Make the box slightly taller and the dip should diminish significantly.

My workbook BOXPLAN-THAM can be used to model THAM-style layouts and optimize them for a particular driver.
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Old 2nd November 2017, 11:44 PM   #5
LORDSANSUI is offline LORDSANSUI  Brazil
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Brian shared many workbook on his website. Congratulations dude.

The Subwoofer DIY Page - Horn Folding

I recently build 4 SS15 modified cab version and it was a hard work. It can be even harder If you don't have all that tools work with woods at home. This design offer you a lot of flexibility, cone correction, grips (handling), and others, but, it's a little hard to make all pieces fit well and guarantee cab stiffness.

I started simulation with 35Hz (-3dB) in mind and and up with 42Hz (-3dB) due to driver diaphragm displacement constrains.

TH 15" flat response to 35Hz (-3dB) - By LORDSANSUI

A more friendly design would be the "MTH" design, I didn't know this one when I started my journey, in fact after study for many mouths I learn that the differences sometimes are on the details.
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Old 2nd November 2017, 11:58 PM   #6
Brian Steele is offline Brian Steele  Grenada
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Quote:
Originally Posted by LORDSANSUI View Post
A more friendly design would be the "MTH" design, I didn't know this one when I started my journey, in fact after study for many mouths I learn that the differences sometimes are on the details.

The MTH fold is definitely simpler. It's however a single-expansion fold so that narrows down the choices of suitable drivers a bit, and the choice of alignment for a particular driver is narrow as well. However, it is a bit easier to build and brace properly (and proper bracing is KEY to getting the best from these builds), particularly as the shortest panels are located in the high pressure S1-S2 zone.
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Old 3rd November 2017, 10:14 PM   #7
Xoc1 is offline Xoc1  United Kingdom
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Quote:
Originally Posted by REIER View Post

Some years ago, I had a dream! I wanted to host my own small cozy rave festival out in the woods. Last summer, I decided to make it real. Needless to say, there was this issue of sound. Being in the woods, limitations such as power consumption and portability presented themselves. I spent most of the summer learning about 12v systems and basic speaker theory.
Hi Rier
Simple question -
What power source & amplifiers are you likely to use for this system?

It's possible to get an amp with plenty of power that works on 12V but the more efficient your speakers are the batteries last longer...

I built a small 12V system this year which was used at some fun events.
I built the rig with a rack mixer and active crossover that was kicking around, and a couple of car amplifiers. I was given some really old Fane 12" mids that were 104 db/W, That helped the batteries last, given that the rig was used with solar power charging.

This is why I think the SS15 would suit It may not go very deep, but it is efficient. If you make it from cheap 12mm ply as jBell did it won't play well at high power, but does that matter if you need to run off a battery?
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Old 4th November 2017, 11:05 PM   #8
REIER is offline REIER
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Thanks for all the response

I must say, the ss15 seem promising. From what I hear, the Tham is a bit easier to build. I do have limited access to tools and skills, so the difficulty degree is kind of a big deal for me at the moment. Accompanied by smaller size, I do believe that the Tham fits my preference for this time being.

I just received an e-mail from lautsprecherteile.de, they said there had been a mistake in their spec sheet and the 15ps100 is same as always. I believe this will be my choice.

I've been going back and fourth on this subject of power supply for a while. With subs, I find this to be a hard workaround. So my plan for the time being is to go for A: a somewhat affordable gasoline fueled generator and a small battery bank, or B: 350 watts of cigs/amorf solar panels along with a huge battery bank. Option A seems to be the cheapest. For amps, I will go for pioneer gm-d8604 for tops, and something from the bassface family for subs.

Tham boxplan, omg! This is amazing. I will try to grasp this. I'm currently doing a stretch of my understanding in this subject, but I think I will need some noobs first aid. Could some one help me understand the first 3 squares in the sheet : Frame width, mounting width and mounting depth?
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Old 5th November 2017, 01:59 AM   #9
xrtze is offline xrtze
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IF you are in Norway, you can get the 15TBX100 around 200€ -> just found it at p-audio, and once you type in Norway in the adress-section, price drops to 209€

btw, this guy here talks about the BMS 15 S 430 v2 to be better suited for the THAM15.
it was cheaper than the 15tbx100 once, but atm doesnt seem to be around.
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Old 5th November 2017, 01:52 AM   #10
Brian Steele is offline Brian Steele  Grenada
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Quote:
Originally Posted by REIER View Post
Tham boxplan, omg! This is amazing. I will try to grasp this. I'm currently doing a stretch of my understanding in this subject, but I think I will need some noobs first aid. Could some one help me understand the first 3 squares in the sheet : Frame width, mounting width and mounting depth?
Frame width - the diameter of the driver's basket. It's usually slightly larger than the quoted diameter of the driver, e.g. 12.25" for a 12" driver

Mounting width - the diameter of the cutout required for the driver.

Mounting depth - the depth of the driver from where the basket is mounted on the cabinet.

These parameters are basically used to correctly illustrate the position and size of the driver in the cross-sectional drawing of the horn in the graph to the right. You can use this to determine whether or not the driver can actually fit into the box

More questions about the workbook - post them to the "Spreadsheet for Folded Horn Layouts" thread.
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