Hi All,
I'm not at all new to electronics DIY and I have some experience with very basic woodworking and access to appropriate tools. That said, the last time I tried to build a speaker cabinet it was in the 9th grade with mitered joints and cleats and, well, let's just say that I didn't get very far.
Ok, that out of the way, being all grown up (outside) and motivated, I've decided that the MTH30 seems like it will be a good companion to my alto TS110s and I want to shake this fear of cabinet building as I have some other projects where ultra-budget is essential.
So, if you guys don't mind, I have some really basic noob questions.
1) I see that the MTH30 calls for MDF. I would rather use plywood for weight, is this a good idea? If so, does it require changing the plan in any substantial way? Any experiences with plywood vs mdf would be helpful here. I don't care about the additional cost if it makes the cabinet lighter.
2) Are the cabinets glued and screwed, or just glued, I can't tell from photos online. They appear to be just glued.
3) From the pictures that I've seen, I'm not seeing anyone line the cabinets with the acoustic dampening material that was found in virtually every speaker made when I was a kid. Do you not need/want this in these type of cabinets? Don't laugh, I really don't know the answer.
4) I'm in the U.S. so getting one of the called for drivers is a bit expensive. I've seen that people have used at least two different alternative drivers that are available from parts express. The RCF LF12g301 and the Goldwood GW-12090. The RCF is $199 and the Goldwood is $99. I also have a couple of JBL tops with 2206s in them that I could borrow temporarily to try out and compare. The question is, what differences should I expect between these drivers? I'm really new to this so I don't yet have any intuition on translating driver specs to real world differences. So, if possible, please be specific and discuss in terms of real world performance differences. I'm not adverse to buying the right driver, but I don't want to waste money on differences that I can't use. I care a lot about sound quality, I care a little less about maximum output.
If it helps this (or these if I build two) are only going to be used for DJ applications, both indoors and out, for small gigs. I largely play somewhat downtempo as well as classic house music, if this helps understand my application. Also, you can assume that they will be powered with an appropriate amp for the driver, so that isn't a factor in which one that I choose.
Thanks in advance,
gs
I'm not at all new to electronics DIY and I have some experience with very basic woodworking and access to appropriate tools. That said, the last time I tried to build a speaker cabinet it was in the 9th grade with mitered joints and cleats and, well, let's just say that I didn't get very far.
Ok, that out of the way, being all grown up (outside) and motivated, I've decided that the MTH30 seems like it will be a good companion to my alto TS110s and I want to shake this fear of cabinet building as I have some other projects where ultra-budget is essential.
So, if you guys don't mind, I have some really basic noob questions.
1) I see that the MTH30 calls for MDF. I would rather use plywood for weight, is this a good idea? If so, does it require changing the plan in any substantial way? Any experiences with plywood vs mdf would be helpful here. I don't care about the additional cost if it makes the cabinet lighter.
2) Are the cabinets glued and screwed, or just glued, I can't tell from photos online. They appear to be just glued.
3) From the pictures that I've seen, I'm not seeing anyone line the cabinets with the acoustic dampening material that was found in virtually every speaker made when I was a kid. Do you not need/want this in these type of cabinets? Don't laugh, I really don't know the answer.
4) I'm in the U.S. so getting one of the called for drivers is a bit expensive. I've seen that people have used at least two different alternative drivers that are available from parts express. The RCF LF12g301 and the Goldwood GW-12090. The RCF is $199 and the Goldwood is $99. I also have a couple of JBL tops with 2206s in them that I could borrow temporarily to try out and compare. The question is, what differences should I expect between these drivers? I'm really new to this so I don't yet have any intuition on translating driver specs to real world differences. So, if possible, please be specific and discuss in terms of real world performance differences. I'm not adverse to buying the right driver, but I don't want to waste money on differences that I can't use. I care a lot about sound quality, I care a little less about maximum output.
If it helps this (or these if I build two) are only going to be used for DJ applications, both indoors and out, for small gigs. I largely play somewhat downtempo as well as classic house music, if this helps understand my application. Also, you can assume that they will be powered with an appropriate amp for the driver, so that isn't a factor in which one that I choose.
Thanks in advance,
gs
1) Use plywood.
2)Use screws unless you like reassembling.
3) Acoustic dampening reduces output in a TH or BR cabinet. For full range cabinets it is used to keep upper frequencies from ringing through the port, for sealed cabinets it can increase apparent volume.
4) The Goldwood only has an Xmax of 5.4 mm, there are 12" with over 20mm Xmax available.
A speaker with double the Xmax can move more air, 6 dB more output.
5) The MTH30 does not look like a particularly good TH design.
Smaller designs don't go as low, but ones worth looking at for DJ use are the THAM, SS15, XOc1's TH18, my Keystone design, the Othhorn, and the Gjallerhorn at the very large end.
2)Use screws unless you like reassembling.
3) Acoustic dampening reduces output in a TH or BR cabinet. For full range cabinets it is used to keep upper frequencies from ringing through the port, for sealed cabinets it can increase apparent volume.
4) The Goldwood only has an Xmax of 5.4 mm, there are 12" with over 20mm Xmax available.
A speaker with double the Xmax can move more air, 6 dB more output.
5) The MTH30 does not look like a particularly good TH design.
Smaller designs don't go as low, but ones worth looking at for DJ use are the THAM, SS15, XOc1's TH18, my Keystone design, the Othhorn, and the Gjallerhorn at the very large end.
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Hi,
Thanks for the response, you cleared up quite a bit. You make two claims about the MTH-30, 1) that it's not a good TH design, and 2) that it's not suitable for DJ use.
Let me first address the second point. I have JBL 18 inch subs for when I need big subs, although, I'm planning to replace those at some point. I'm fully aware that I'm giving up low end extension but even a 12" sub will add some nice bottom end to my little altos. I'm not looking for this to be my only sub, but I do want it to be small. Of the alternatives that you suggested, if I found the right information, only the SS15 and your THAM series is 15 or smaller. The rest are 18" subs, correct? I couldn't find plans for the XOc1 or the SS15, but in the photo of the builds, it looks a bit larger. So, I'm not at all interested in building an 18" box right now. I want to make mistakes with smaller pieces of wood!
I couldn't find a lot of detail about the MTH-30, and, discovering your THAM series, your own THAM-12 and THAM-10 are actually quite appealing. I will be using it with my TS110as which go down to about 70hz. Alto claims max SPL of 120 dB continuous. Given that the THAM-15 is about 1/3 more volume than the MTH30 and that the driver is 1/3 more weight and cost, I'm still leaning towards a smaller sub. Also, the 10" driver is almost as much as the 12" driver and takes significantly less power. So, I'm still feeling that the 12" is still the right size for me.
So, given that I'm fully aware that this is a compromise, and that I'm looking for something in a smaller cabinet, could you perhaps elaborate a bit on (1) above? Is your THAM-12 design a better design, and if so, why? I do like that 1) it's a bit smaller than the MTH-30, and 2) that, to my naive eyes, the B&C driver appears to be a bit beefier than the RCF (but also less sensitive) for about the same price.
Thanks for the response, you cleared up quite a bit. You make two claims about the MTH-30, 1) that it's not a good TH design, and 2) that it's not suitable for DJ use.
Let me first address the second point. I have JBL 18 inch subs for when I need big subs, although, I'm planning to replace those at some point. I'm fully aware that I'm giving up low end extension but even a 12" sub will add some nice bottom end to my little altos. I'm not looking for this to be my only sub, but I do want it to be small. Of the alternatives that you suggested, if I found the right information, only the SS15 and your THAM series is 15 or smaller. The rest are 18" subs, correct? I couldn't find plans for the XOc1 or the SS15, but in the photo of the builds, it looks a bit larger. So, I'm not at all interested in building an 18" box right now. I want to make mistakes with smaller pieces of wood!
I couldn't find a lot of detail about the MTH-30, and, discovering your THAM series, your own THAM-12 and THAM-10 are actually quite appealing. I will be using it with my TS110as which go down to about 70hz. Alto claims max SPL of 120 dB continuous. Given that the THAM-15 is about 1/3 more volume than the MTH30 and that the driver is 1/3 more weight and cost, I'm still leaning towards a smaller sub. Also, the 10" driver is almost as much as the 12" driver and takes significantly less power. So, I'm still feeling that the 12" is still the right size for me.
So, given that I'm fully aware that this is a compromise, and that I'm looking for something in a smaller cabinet, could you perhaps elaborate a bit on (1) above? Is your THAM-12 design a better design, and if so, why? I do like that 1) it's a bit smaller than the MTH-30, and 2) that, to my naive eyes, the B&C driver appears to be a bit beefier than the RCF (but also less sensitive) for about the same price.
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weltersys, (+1)
ghettosynth, You probably wouldn't be able to achieve lower/sub bass frequencies region with that nice driver of yours RCF LF 12G301.
I would do like you, finding a nice driver and stick to it, but one that works in a horn and goes low, that one is good for a horn and doesn't go low in my list.
Get opinion from a professional or then listen or measure the drivers yourself.
I definitely go add a pair to your PA active speakers, like the Alto TS110, and choose something in the trends of the EMINENCE Omega Pro-15a or the EMINENCE KILOMAX PRO 15 A. But hey this me. I have horns and they don't go low (maybe 40Hz) but they can be really noise if you push the limits. Your driver looks excellent for a horn but it doesn't go low in my books... That's your choice.
Bill Fitzmaurice Design DIY Kits | Speaker Hardware
ghettosynth, You probably wouldn't be able to achieve lower/sub bass frequencies region with that nice driver of yours RCF LF 12G301.
I would do like you, finding a nice driver and stick to it, but one that works in a horn and goes low, that one is good for a horn and doesn't go low in my list.
Get opinion from a professional or then listen or measure the drivers yourself.
I definitely go add a pair to your PA active speakers, like the Alto TS110, and choose something in the trends of the EMINENCE Omega Pro-15a or the EMINENCE KILOMAX PRO 15 A. But hey this me. I have horns and they don't go low (maybe 40Hz) but they can be really noise if you push the limits. Your driver looks excellent for a horn but it doesn't go low in my books... That's your choice.
Bill Fitzmaurice Design DIY Kits | Speaker Hardware
Hi!
Already made Made 6 of them .
-Plywood, plenty of good glue, and screws is a must; I use plenty of T-50 pin nails.
BeA Deutschland - Befestigungstechnik
-no dampening;
-best drivers from tested ones are:
12PS100
12ps100 - Parts Express Ships Fast and Ships Free
12CL76
B&C 12CL76 12" Neodymium Woofer 294-695
With these drivers you could take a four string bass guitar and play the notes thru it as it should.
Correct band sets helps to maintain drivers health; Low cut around 40Hz at minimum; high cut at 96Hz was the best performance in my opinion.
Let your ears also help in judgement.
Regards,
Already made Made 6 of them .
-Plywood, plenty of good glue, and screws is a must; I use plenty of T-50 pin nails.
BeA Deutschland - Befestigungstechnik
-no dampening;
-best drivers from tested ones are:
12PS100
12ps100 - Parts Express Ships Fast and Ships Free
12CL76
B&C 12CL76 12" Neodymium Woofer 294-695
With these drivers you could take a four string bass guitar and play the notes thru it as it should.
Correct band sets helps to maintain drivers health; Low cut around 40Hz at minimum; high cut at 96Hz was the best performance in my opinion.
Let your ears also help in judgement.
Regards,
Thanks, to be clear, did you mean 6 of the MTH30? I read in another thread that the 12ps100 didn't simulate well in that cabinet so I want to make sure that you aren't talking about the THAM12?
Nice. From what I've read, the TH designs are quite musical.
Sure, I appreciate the input. The simulations paint a pretty strong picture for the 12" subs. None of them will go that low, that's ok. I get that. I admit, the THAM15 looks appealing from many angles, but, for this first build I want to keep the size manageable. I may change my mind between now and when the build starts, but for the time being, I feel that a small 12" sub suits my needs.
What do you mean by "really noisy?"
tnx,
gs
Hi, I have a portable PA build in progress, with a pair of Peavey Impulse 100's, very similar size and output to your alto's. I looked at every compact tapped horn, horn, bandpass horn, ported horn, t-tqwt, and bandpass design out there over a period of several months, tried modeling my own, and eventually decided on a pair of 15" subs in a compact slot ported box with 35hz tuning:
http://www.diyaudio.com/forums/subwoofers/219923-ultra-compact-ported-15-dayton-ref-ho.html
In a 20x22x16" 50lb build, having low extension (usable in room to 30 hz w/o eq) and no need for digital time delay to time align the mains was a big bonus, while still getting nearly the sensitivity (95 db/w/m/2pi) and max output of a compareably sized horn. I am extremely happy with their performance so far - very clean, powerful and musical.
I made no claim that the MTH-30 is not suitable for DJ use.
Many DJ's use total garbage, 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.
The Tham is Anders Martinsson's design, not mine.
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
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.
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
Turbodawg,
You are using the Dayton Reference 15 four ohm driver in a very small low tuned ported box.
It is only 87 dB one watt one meter at 100 Hz, and drops considerably in sensitivity from there, probably in the 80 dB one watt one meter range at Fb.
Have you any measurements?
Art
Hornresp sim's to a 40-50hz peak over 95 db/m/2pi at 2.0V input, aka nominally 1w, and -3 db around 34 hz. It has a mildly peaking response with lots of gain from the port, like a house curve, and I'm using a bit of overlap at the crossover to fill in the midbass. Dayton's spec sheet calls their shown response below 200hz as "not actual". These simmed higher sensitivity than other smaller drivers, the only thing comparable was some of the eminence LF models.
I could use my analog rat shack SPL meter with correction data to pull some numbers, if I get around to it.
Running full range music, bass heavy, I've hit over ~115db peaks in the middle of the room, the RS meter is accurate "enough" for that, without the system breaking a sweat or the subs near xmax.
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I'll trust it's loud to you
.You claim a response 8 dB above a manufacturer's specification, and have not bothered to put a dB meter in front of the cabinet?
Please show us the Hornresp input screen and FR that result in an 8 dB sensitivity increase over the manufacturer's specifications and a measured response at a few frequencies.
I'll trust it's loud to you
You claim a response 8 dB above a manufacturer's specification, and have not bothered to put a dB meter in front of the cabinet?
Please show us the Hornresp input screen and FR that result in an 8 dB sensitivity increase over the manufacturer's specifications and a measured response at a few frequencies.
I'll see what I can do, but I've got many projects in process right now. Taking an inaccurate measurement of these is not a high priority. I'm confident of my ablity to use simulation software and casual observation seems to indicate they are performing as expected.
Hi Pasc,
As far as I can tell, the DSL TH Mini uses the B&C12TBX100, which on paper is a tiny bit more sensitive than the BC 12PS100, 2 Hz lower Fs and has 9mm Xmax and 11mm Xvar, and 300 watts more power handling.
In my testing of the BC18SW115 I found the Xvar excursion and rated power handling completely usable, so if one can afford the 12TBX100, it is worth the extra output potential in whatever box it is in.
Still using the Keystone?
Art
Even a quick measurement would probably be more telling than the simulation.
Using the Dayton Reference 15 in a simulation of about 90L net (20x22x16 using 3/4") 2 volt with a 35 Hz Fb does show 95 dB at 60Hz, 91.96 at 40Hz, but only 89.34 at 35 Hz. At 30 Hz it shows 85 dB.
Hornresp is very useful, but it often shows peaks larger than reality, and drooping upper response (or more LF response) than real measurements.
Comparing the real measurement of my Lab 2x12" to the sim, the sim shows the response at 40 Hz to be some 10 dB higher than 500 Hz, while it is actually 2 dB less.
I built the Lab 2x12" before using Hornresp, that peaky port "boom" Hornresp predicts would have scared me off.
If the same holds true for your Dayton Reference 15 in a 20x22x16 35Fb box, it may be closer to 87 dB than 95 dB sensitivity.
Art
Attachments
Hi!
12PS100 Item Price: $205.95
12TBX100 Item Price: $294.95
Difference............+ $ 89.00 43%more per driver.
If you have the money for the difference of cost and and so for bigger amp to earn some 1.5dBs ok.
Not have chance to test the 12TBX100 yet.
When tested in the TH18, the 18TBX100 beside 18LW2400, it didn't impress me so much. 2000W to do the same as the 18 Sound one with 1300W, and travelling a lot despite carefull low-cut set.
Keystone: Despite good results, after tests, shame it is parked at my garage as is the TH18. Driver costs to much here due taxes. But was a good study to me.
Regards,
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HornResp doesn't take losses into effect, if I remember correctly. Gotta be a bit careful when using it to sim vented boxes.
Do you have access to HornResp predictions or actual measured FR or PR response curves for the MTH30?
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.