MTH30 Questions : Complete Noob!

Brian Steele · 2013-01-23 9:50 pm

weltersys said:
No, just my meat computer generated response curves .

I'd like to see sims, actual measurements, or direct comparisons if anyone has made them, but found none in my quick review of the MTH30 threads I came across.

Maybe Pasc could compare the MTH30 to the XOC1 TH18 or my Keystone and give us an idea of FR, sensitivity and output potential.

I think a fairer comparision would be "like for like", or, in other words, given the volume the MTH occupies, can better be done (output, low frequency extension and passband width).

My POC TH is a bit smaller and goes lower, but I'll bet $$$ to doughnuts that it's not as efficient. It was a compromise I was prepared to live with. I'd like to see what compromises were made in the MTH30's design.

ghettosynth · 2013-01-24 12:28 am

weltersys said:
I made no claim that the MTH-30 is not suitable for DJ use.

Of course you're right, I misinterpreted your assertion that "other TH cabs" are suitable for DJ use" as an implication that the MTH-30 was not. My apologies; I really appreciate your input on this. I'm trying to make a good decision with limited knowledge based on the practical limitations that I'm willing to live with.

Many DJ's use total garbage,

Agreed!

the MTH-30 would be a distinct step up.
My statement that the MTH30 does not look like a particularly good TH design is based on comparing it to others that appear better in terms of output vs. size and frequency response.

I see.

The Tham is Anders Martinsson's design, not mine.

Again, my apologies.

The B&C drivers are well suited for TH use, you will find that though they appear to be less sensitive, they don't fold up like a cheap suit at high drive levels as lighter, more sensitive cones (Eminence 3015LF, etc.) do:

http://www.diyaudio.com/forums/subwoofers/175658-tham15-compact-15-tapped-horn.html

Also good to know. Like I say, I dislike paying twice a lot more than I dislike paying for the right thing.

The SS15 is Jbel's design:
http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge.html

Since my Keystone, the Xoc1 TH18, the Othhorn, and the Gjallerhorn are all larger than you want, I won't bother linking them.

Thanks for the links.

This design is smaller than the Tham 15 or SS15, has more LF output, but less output above around 50 Hz Hz:

FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

It is about the size of a JBL SRX 718, but has more LF output, it goes deeper than a SRX 728. Using a pair of TC EPIC 12" instead of the Lab 12s, it would be very close to the same output as the 728 in less than half the size.

I have a pair of the WS 2x12" cabinets for sale unloaded if you are interested.

Art

I like the low extension and smooth sim response, but I wonder if it's a good trade off for me with the small alto TS10s. That said, they might work well for me, although the drivers cost more per cab. They look easy enough to build, in fact, easier than the TH horns, but, I don't like the geometry as much for my small sub. Nonetheless, I can't lie, I don't like any of the subs that I have now and those might be a better overall compromise.

I might be interested in your cabs just to save time. It's not like I don't have other diy projects to occupy my time. Could you PM me your price and zip code, and perhaps some pics?

tnx

sebDIY · 2013-01-24 4:13 am

the MTH-30 would be a distinct step up.
My statement that the MTH30 does not look like a particularly good TH design is based on comparing it to others that appear better in terms of output vs. size and frequency response.

Sorry but I don't agree with you,. Have you ever tried MTH-30? I don't think. I have four of them with LF12G301, and they sound great, clean, with a lot of level for its size.

MTH-30 is very popular in Europe, probably the most used 12" bass DIY speaker here. Search on freespeakerplans or speakerplans site, you will find infos.

sonomanie · 2013-01-24 11:10 am

TH Mini

The Th mini uses a B&C 12PS100

PASC · 2013-01-24 12:47 pm

Hi!
http://img5.uploadhouse.com/fileuploads/17204/17204401a801edb22e0c7a1e8fa8cc89bbbc3b77.jpg
http://img8.uploadhouse.com/fileuploads/17204/1720441461afb341ab228abd77aaafd8a25862ed.jpg
Compared 1:1 with THAM 15 and with db miniscoop12

1st miniscoop, 2nd MTH, 3rd THAM15.

Miniscoop is a professional product of a friend factory with 18 Sound OEM drivers.
In the THs we tried several local label drivers, 18 Sound drivers and B&C drivers.

We played playback good music, Bass guitar live, also eletronic music.

THs exam would be hear how the notes are coming live thru it from the bass guitar.

The driver that gives more SPL 40/60Hz region will not define the 80/100Hz region.
When you stack more boxes it will be worst for live jazz, live simphonic rock and that's why we pay so much attention to sound definition, when we would separate wheat from chaff.

Maybe I have not yet listened THAM 15 with the correct driver, but from 60 down...

I can buy 4 12CL76 for the cost of one blueship 18" to habbit TH18, or Keystone, and with my age, I prefer carry MTH30, one man lift box.

Regards,

weltersys · 2013-01-24 6:36 pm

ghettosynth said:
Like I say, I dislike paying twice a lot more than I dislike paying for the right thing.

Thanks for the links.

I like the low extension and smooth sim response, but I wonder if it's a good trade off for me with the small alto TS10s.

I might be interested in your cabs just to save time. It's not like I don't have other diy projects to occupy my time. Could you PM me your price and zip code, and perhaps some pics?

tnx

If you look through the link threads, you will see the only pictures I currently have of the Welter Systems Lab 2x12".
You will also notice that the Hornresp simulation shows a peaky port response that is absent in the actual Smaart tests of the cabinets.
You can also see the direct comparison to the almost "industry standard" JBL SRX 728.

The trade off between real 30-40 Hz LF extension in a small box (The WS 2x12") and the chest thumping 60-100 response of the similar size tapped horns is one you need to decide on.

I'd sell the pair of used WS 2x12" cabinets each loaded with one Lab 12 for $700 plus shipping from 87505 (Santa Fe, NM) unloaded for $400. Shipping weight is around 80 lb with one driver, about 55 unloaded.

Art

tb46 · 2013-01-24 9:53 pm

Hi,

I did a "quick and dirty" in Hornresp on the MTH30 (3 sections only), wonder how that compares to measurements?

Regards,

turbodawg · 2013-01-24 10:00 pm

Just happened to stumble across this as a (somewhat) compact sub that gets down to 35hz or below........

Cubo Sub
(scroll down to see plan)
cubo sub - Speakerplans.com Forums - Page 1
http://www.diyaudio.com/forums/subwoofers/192707-best-sub-5.html

Xoc1 · 2013-01-24 10:42 pm

The Cubo sub is compact but really wants a decent 18" driver.
There have been quite successful multiple builds of the Cubo 18 in the UK using the Precision Devices PD1850. The build is easy but best performance still relies on quality drivers and amps.

PASC · 2013-01-25 12:12 am

Hi

Googling find a youtube video with 4 of them loaded with PD12SB30 played in room with audible recording eletronic music.
Will not show all of what it is capable but can give an idea how the sound comes out...

4 MTH-30 Tapped Horn Subwoofer - YouTube

Regards,

sebDIY · 2013-01-25 12:24 am

Measurement (calibrated) from one of my MTH:

An externally hosted image should be here but it was not working when we last tested it.

tb46 · 2013-01-25 4:01 pm

Hi sebDIY,

Thanks for that. It basically confirms the Hornresp simulation (real life smaller peaks, etc.). How high up do you use it?

Regards,

weltersys · 2013-01-25 9:58 pm

sebDIY said:
Measurement (calibrated) from one of my MTH:

An externally hosted image should be here but it was not working when we last tested it.

Thanks for posting the chart, what were the measurement conditions?
What drivers did you use in your cabinets?

Looks like a classic example of Hoffmann's iron law, low, loud, small, pick two

.

In your example of the MTH, the lower octave of typical pop musical bass is sacrificed for small and loud, response is 25 dB down around the low B (31.5 Hz) on a bass guitar.

As usual, smoother than Hornresp would predict.

Brian Steele · 2013-01-25 11:28 pm

weltersys said:
As usual, smoother than Hornresp would predict.

I want to see the impedance response curve. That will show how close the sim matches the actual design.

sebDIY · 2013-01-26 12:35 am

Looks like a classic example of Hoffmann's iron law, low, loud, small, pick two

.

In your example of the MTH, the lower octave of typical pop musical bass is sacrificed for small and loud, response is 25 dB down around the low B (31.5 Hz) on a bass guitar.

For my use it's perfect. I was searching a light cabinet (mine is 23Kg with ferrite driver, this is the lightest of all cabinets I've tried), searching also clean sound, and it is, with ability to make strongest level in this size. I have compared with some 18" bass reflex. The 18 BR goes lower, but MTH-30 makes more level and is more dynamic, also lighter and smaller.

The loudspeaker is LF12G301 RCF, measurement groundplane 2 meters without any wall into18 meters perimeter

Without any any eq, you can cross at 110/120hz without hearing any ugly resonance, but I think it is usable above 120Hz with Eq cutting peaks. I know some people cross it 150Hz. I use most of the time for wedding: 2 MTH-30 and 2 ZX1 EV. I have made 200 people without any problem in this configuration and I think it can do even more.

weltersys · 2013-01-26 12:48 am

Brian Steele said:
I want to see the impedance response curve. That will show how close the sim matches the actual design.

Oliver's (TB46)Hornresp FR peak and dip locations matching senDIY's measured peak and dip locations indicate the sim matches the design very closely.

I find it interesting that most in the DJ and PA business are perfectly willing to trade LF extension for SPL.

Art

turbodawg · 2013-01-26 1:08 am

weltersys said:
Oliver's (TB46)Hornresp FR peak and dip locations matching senDIY's measured peak and dip locations indicate the sim matches the design very closely.

I find it interesting that most in the DJ and PA business are perfectly willing to trade LF extension for SPL.

Art

Lots of small pa setups don't use subs, so in comparison this is very good.

weltersys · 2013-01-26 1:23 am

turbodawg said:
Lots of small pa setups don't use subs, so in comparison this is very good.

"Very good" is a relative term, like "good enough".

The Mackie HD1502, a fairly small speaker on a stick using a 15" and 1" exit HF driver drops off only 1/6th octave above the MTH30.

sebDIY · 2013-01-26 1:26 am

I find it interesting that most in the DJ and PA business are perfectly willing to trade LF extension for SPL

Most wedding rooms I work got reverberation, and can sound "whaouwhaouwhaou" in the infrabass range, espacially with very compressed music, so I prefer, from far away, a truncated and dynamic bass cabinet, more listenable, than a slow sub.

ghettosynth · 2013-01-26 2:00 am

weltersys said:
Oliver's (TB46)Hornresp FR peak and dip locations matching senDIY's measured peak and dip locations indicate the sim matches the design very closely.

I find it interesting that most in the DJ and PA business are perfectly willing to trade LF extension for SPL.

Art

Well, for me at least, I'm not "in the business", so to speak, it's a hobby. I specifically need something "one man" portable." If it's not easy to grab and go, I just won't take it. No 18" sub, and most 15" subs are not just grab and go for me.

Well, I'm still debating on what exactly that I'm going to do here, I'm fairly certain that I'm going to build at least one pair of small 12" TH subs.

I have some more pedestrian questions.

First, does anyone have any specific recommendations for the following items:

1) Connector plates, I want to use speakons.
2) Finish, I'm leaning towards some sort of paint, but I want to know what people like and use, and what's cost effective.
3) Handles and pole mounts.

Given the simulation results and measurements here, I'm not seeing a lot of difference between the low frequency extension of the MTH30 and the THAM12, which is a bit smaller. I also notice that hornresp really considers only the dimensions of the horn and the properties of the driver, and how the horn is folded, holding all else constant, doesn't come into play in the sim. I have no sense of how the quality of the horn fold impacts real results, but, given what I've read elsewhere on this forum, performance is relatively insensitive to small deviations holding all else constant.

Consequently, it appears that I can trade off some SPL for LF extension in the THAM12 by just making the cabinet about 3 to 4 inches taller. After that, it appears to be diminishing returns for additional length. I simed this using the 12PS100. Looking at the design, it seems that I could scale the height in the build plans fairly easily without dramatically affecting the taper of the horn or any other critical dimensions. Anything that I'm overlooking here?

Finally, I haven't sim-ed it yet, but, I'm leaning towards the B&C 12NDL76 for weight reasons. Any thoughts on this, are there any other good choices of driver in the 10 pound range that I should consider? In particular, is there anything less expensive that would work almost as well?

tnx,
gs

MTH30 Questions : Complete Noob!

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