Fibre Glass MT121 Horns.
Printed From: Speakerplans.com
Category: Plans
Forum Name: MT122
Forum Description: Discussion / Questions about the MT122
URL: https://forum.speakerplans.com/forum_posts.asp?TID=10013
Printed Date: 26 March 2026 at 11:31pm
Software Version: Web Wiz Forums 12.08 - https://www.webwizforums.com
Topic: Fibre Glass MT121 Horns.
Posted By: adambomb
Subject: Fibre Glass MT121 Horns.
Date Posted: 15 May 2007 at 10:26pm
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Hi All,
As some of you may know I am looking for some mid / top for my so far entirely SP rig (4 x X1s and 6 HD215s).
I have been going in all sorts of directions with this so far:
1. Buy SH Turbo, Martin, EAW etc horn loaded mid tops. (looking at around £500 per box)
2. Buy Dodgy Chinese knock offs. (shipping costs and general "bad vibe" about this.. around £500 each agian, but brand new).
3. Build MT121s. (the amount of work involved and therefor cost for me seams to be very high.. and I may want 6 in the end so may cost more in the long run).
4. Buy Fibreglass horns... but the prices are soo silly ranging from £350 - £200.. way too much for what it is.
5. Make Fibreglass horns... and build a box to chuck em in.
So...
The last option seams to me a great way of learning a new skill... and totaly in keeping with the SP ethos (IE home made - could be repeated by any member).
So far I have looked at the tooling costs (making the moulds)... which come out at around £250... (that includes making a plug, the casting a mould from that, then making a gloss plug from that mould)... plus a little diy time with some filler.
I have also looked at the production costs.. which are suprisingly low! (massive profits made on these items from pro audio retailers.. massive!).
This would include 3mm fibreglass, renforced where nescecery, flanges and bowls to put over the drivers (probably have to drill them to suit driver)... basicaly ready to chuck in a box.
Personaly I think this might be the way to go... and might also help a few other SP members with there mid / top needs... for far less than they could get them elsewhere.
I'm going to go ahead with the project I think (unless a cheap set of TSE 111s or THL 811s come in the near future).
So... on the back of this.. if it happens... I will be able to supply a complete fibreglass horn for around £60!! (that's near enough cost price)
So anyone up for fibreglass MT121 Horns? Is this a good idea? Lemme know you thoughts people!!?!?!
Would Rog mind???.. I'm not exactly doing it for the money, Rog will know there's no mark up on that price, just enabling other peeps to make use of my moulds really.
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Replies:
Posted By: ceharden
Date Posted: 15 May 2007 at 10:59pm
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The MT122 is a compromise horn to enable it to be made out of wood at all. If you're going to go to the trouble of making a fibreglass horn, you might as well spend some time refining it. Eg making it more circular or even think about a phase plug of some kind. I've been thinking about doing this for some time but have too many other projects on the go. I'd certainly be interested in some flares and having some input into the design if you want? |
Posted By: adambomb
Date Posted: 15 May 2007 at 11:16pm
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Please Please Please.!!!..
This is exactly the response I was looking for.. this could be the SP communitys poor mans porn?
Having your help would be fantastic!
I would have a go at HornResp myself... but I'm a total newb.
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Posted By: ceharden
Date Posted: 16 May 2007 at 12:28am
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Excellent. Will drag out some of my previous investigations. You are going to need to learn Hornresp! Download it, the help section is quite useful. Start by simulating the MT121 as-is with your driver of choice then start playing with the throat, mouth, length, flare type and see what happens. I would like something which has a dispersion of about 60x40deg and is usable from about 160Hz to ideally a crossover at 1.2kHz. I'm using two direct radiating 12" drivers at the moment but would like to move over to a single horn loaded. |
Posted By: Rockin
Date Posted: 16 May 2007 at 7:44am
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Yeah i'd be up for some too. Hope this project comes off  |
Posted By: mykey
Date Posted: 16 May 2007 at 7:58am
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4. Buy Fibreglass horns... but the prices are soo silly ranging from £350 - £200.. way too much for what it is.
5. Make Fibreglass horns... and build a box to chuck em in.
------------- ......just all them hanging there like giant bananas. |
Posted By: biotec
Date Posted: 16 May 2007 at 9:56am
| It would be quicker (and more c*ntish) to reverse mould an existing fiberglass horn (martin, turbo, funktion, eaw, etc) and base yours on that. |
Posted By: Richard Hart
Date Posted: 16 May 2007 at 10:23am
£300 a pair!!!
That's a bargin Mykey! I imagine if you loaded those horns with a couple of the P audio neos they'd rip your head off!
What will those horns go down to?
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mykey wrote:Posted By: adambomb
Date Posted: 16 May 2007 at 10:28am
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I have seen the Jan Audio ones... and they look great, but they are double 12".. I want single.. and I think (!?!) most other people do too... and that's still £150 each.. which equates to almost 3 times the cost price.
I know Jan Audio make a single 12" with a comp mounted in the mid horn... but these are a bit more pricey.
About reverse engineering another horn... could be done, but I think the end result would be better with an original mould... and it's also far more SP to build our own ay!
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Posted By: adambomb
Date Posted: 16 May 2007 at 10:31am
| Ceharden.. I have HornResp.. I will start where you suggested.. your freg response and dispersion requirments sound perfect for me too. |
Posted By: adambomb
Date Posted: 16 May 2007 at 10:32am
| Anyone got suggestions on drivers... keeping costs reasonable ('m thinkin something from P.Audio). |
Posted By: ceharden
Date Posted: 16 May 2007 at 10:37am
| @Mykey: We've also been waiting a very long time for you to put some more detailed specifications on the Janaudio site. Ideally full response and polar plots would be nice but just an idea of the frequency response and the nominal coverage angle would be a start. |
Posted By: ceharden
Date Posted: 16 May 2007 at 10:57am
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There are some nice drivers by B&C,18Sound,PD that are suitable. In fact the drivers I'm using in my twin 12" boxes can be horn loaded. 12PE32 is a real horn driver but it's ferrite so if you want to keep the weight down..... 12NDL76 is lightweight and will work well in a horn The PD alternative is the 12MH25. From 18Sound you could use the 12ND610 or 12ND710 both of which are quite reasonable money. If you want to go P.Audio then the SN12B is the main option. |
Posted By: adambomb
Date Posted: 16 May 2007 at 11:41am
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I'm completely open to your suggestions... personally I don't care about weight (but then my rig isn't lugged about every week end).
Only suggested P.Audio as the drivers are available quickly (unlike PD) and they seams to be good value for money / well built.
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Posted By: adambomb
Date Posted: 16 May 2007 at 11:50am
| Shall I start with the SN12B... everyone happy with it? are the specs on the P.Audio site right? (as I notice some arn't) |
Posted By: Tekasis
Date Posted: 16 May 2007 at 12:21pm
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Any reason Adam why you'd go for the SN-12B over the SN-12MB ?
I heard a double 12'' mid cab (up & over) the other day loaded with a pair of P.Audios SN-12MB's & it sounded very nice.
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Posted By: ceharden
Date Posted: 16 May 2007 at 1:06pm
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@Tekasis: For a direct radiating cab, the SN12MB is the right driver, for a horn the SN12B has the correct parameters. The SN12MB also has a smaller voice coil and lower power handling. Adam, if you start the design around the SN12B any of the other drivers I mentioned should also work fine. |
Posted By: adambomb
Date Posted: 16 May 2007 at 2:48pm
Am I anywhere Near : (doesn't look right to me - told you I was a newb)
 |
Posted By: Tekasis
Date Posted: 16 May 2007 at 8:36pm
Thanks for that info mate. All this time I was thinking the 12B was a bass driver.
How do you think the SN-12B's would sound in your double 12'' cabs compared to the B&C's you got in there ?
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Posted By: ceharden
Date Posted: 16 May 2007 at 10:17pm
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I've looked at using the SN12B's but their parameters are heavily geared towards horn loading. If you put them in a reflex box it would have to be quite small and tuned quite high and you'd still not get much in the way of low end out of them. What you would get however is a very tight, well defined sound. My experience of the P.Audio SN range is that they are good drivers for the money, however they can't match B&C etc for ultimate sound quality,power handling etc. The drivers I use (currently B&C 12NDL76/12MH32, soon to be 18Sound 12ND710) are quite close to the horn loading end of the spectrum too but are just about usable in a reflex box. Once I've put in a crossover at 120-160Hz I might as well have just used a sealed rear chamber but the reflex loading means that if necessary the cabs can be persuaded to do full range or a low crossover (70-80Hz say) to a sub only cab eg X1. As it is I've had to put a +5dB low shelf at 160Hz to flatten the response down to the crossover point. Bit of a deviation from the thread topic but hope that helps. |
Posted By: Tekasis
Date Posted: 16 May 2007 at 10:54pm
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Cheers for that Chris. I've decided on what most of you guys say & buy top class stuff first time round, so will give one of these B&C's a try. Not the Neo ones.
I'll be trying out some 10's. I got my mind on the 10MD26, you know anything about this model ? You ever heard them ? Or from the spec you'd recommend different ? It's for use in a standard double 10'' A.S.S reflex cab for mids.
http://www.bluearan.co.uk/menu/index.php?id=BAC10MD26&product=B!amp!C_10MD26_10!dquote!_300W_Low_Frequency_Driver&browsemode=category - http://www.bluearan.co.uk/menu/index.php?id=BAC10MD26&product=B!amp!C_10MD26_10!dquote!_300W_Low_Frequency_Driver&browsemode=category
Nominal Impedance; 8 Ohm
Minimum Impedence; 7.2 Ohm Nominal Power Handling; 350 W Continuous Power Handling; 700 W Sensitivity (1W/1m); 100 dB Frequency Range; 80 - 4000 Hz Net Weight 7.3 kg (16.1 lb) I also want to get a couple B&C 12''s for some flared cabs but not sure which one to use as there are so many to choose from.
I remember the last time I heard Fable Sound System, & their double 12 cabs were loaded with B&C 12PE32 which sound superb.
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Posted By: mykey
Date Posted: 17 May 2007 at 9:21am
------------- ......just all them hanging there like giant bananas. |
Posted By: Richard Hart
Date Posted: 17 May 2007 at 10:00am
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Mykey. You are skirting around the subject...... What about the specs? Is this why they're so cheap? |
Posted By: mykey
Date Posted: 17 May 2007 at 10:30am
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http://zmatek.jinak.cz/diy/pbaudio/coaxialhorn12-2/show_construction.asp.html - http://zmatek.jinak.cz/diy/pbaudio/coaxialhorn12-2/show_construction.asp.html ------------- ......just all them hanging there like giant bananas. |
Posted By: adambomb
Date Posted: 17 May 2007 at 10:56am
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That looks like a better price.. for sure! (although that still represents a good 100% markup.. wish I could make those kinda margins on the kit I sell.. but then again.. I probably sell more, bigger market).
Couple of things worry me...
1. The horn looks straight (ie, not exponential)... does this mean they are less efficient??
2. The link above takes me to a page showing the complete cabs... but still no plots / data... do you have any more details?
3. No idea what drivers they where designed for (although the text does mention some B&C models).
4. Any clue on splay angles?
5. How is the compression driver supported... would I have to home brew this bit?
6. Is the compression driver horn included in this price (if so it obviously gets more attractive).
Might be interested.
Cheers,
Adam.
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Posted By: adambomb
Date Posted: 17 May 2007 at 10:59am
| also... do they have flanges on the rear for driver mounting / sealing to a baffle? |
Posted By: ceharden
Date Posted: 17 May 2007 at 11:10am
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@Tekasis: If you can give more exact details on the cabs I can probably give you more accurate recommendations. The 10MD26 is another driver designed mainly for horn loading. I haven't heard it but from the specs: While it would work to some extent in a reflex cab it's not ideal. If you want to use it for real midrange ie above 200Hz then either a sealed cab or a short horn would be best. What frequency range do you want to cover? I'm slightly confused that you want 12" and 10" drivers doing a similar job. Is this for the same system or are you working on two different setups? I've been a mainly B&C user til now but I'm awaiting a delivery of various 18Sound drivers. If the actual drivers are as good as the specs suggest I think I'm going to be using a lot more of their stuff. The 12" neo drivers especially look very nice. Prices are good too. Depends on the flare design and the intended useage but 12PE32 or 12NDL76 are your main options from B&C. |
Posted By: Tekasis
Date Posted: 17 May 2007 at 2:36pm
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The cabs are shown over on this thread Chris. http://www.speakerplans.com/forum/forum_posts.asp?TID=7328&KW=10&PN=4 - http://www.speakerplans.com/forum/forum_posts.asp?TID=7328&KW=10%27%27%27%27&PN=4 Can you reply on that one so it don't look like I'm Hi-Jacking this Fibre Glass Horn thread ?
Appolgies Adam.
Cheers.
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Posted By: jb007
Date Posted: 17 May 2007 at 10:31pm
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I discused mid freq. speakers with a lot of peole and very often I got answer that BC 12NDL76 is great(one of the best) speaker! 12MH32 is maybe a little bit better, but this speaker is more HEAVY (7,4kg vs ndl76-4kg)
Does somebody have scheme of good horn for 12ndl76? ------------- http://www.djforum.cz - http://www.djforum.cz |
Posted By: ceharden
Date Posted: 17 May 2007 at 11:10pm
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I've tried the 12NDL76 and 12MH32 in my little wedges (just happens to be the two 12" drivers I have here!) and they sound pretty much identical. The 12MH32 maybe has a slightly smoother top end but that's only an issue if you're crossing at 2kHz or higher. I think the fact that mid horns are difficult to DIY build is the reason why there aren't many plans out there. Hence why for the time being I'm going with a pair of direct radiating drivers. Ultimately I think I'm going to have to design my own. |
Posted By: Richard Hart
Date Posted: 17 May 2007 at 11:42pm
Yeah, but have you got the specs for the 212 and the 112? I.e. polars, response graphs. This is nothing but a DIY project.
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Posted By: mykey
Date Posted: 18 May 2007 at 3:09am
complete, whole , one.
1. Waveguide
2.Dont have, but my ears told me they were the bollox
3.B&C's
4.40x40 the 2'' is a B&C horn
5.done for you, just 4 bolts
6.yes
100% mark up
 £140-50%=70£70 to make a 8mm thick 12'' horn, 2'' horn and heavy gauge 2mm steel bracket in the UK?
are you on drugs?
------------- ......just all them hanging there like giant bananas. |
Posted By: ceharden
Date Posted: 18 May 2007 at 9:22am
| Is it possible to mount an alternative HF flare in those horns? I know we've touched on this before but do you think the flare would work without a HF driver at all? Or would it be better? Or could you mount a phase plug on the HF mounting bracket instead? |
Posted By: gingerbiscuit69
Date Posted: 20 May 2007 at 4:39pm
2) great sales talk there ... imagine that on the Void site, the stasys3 mk2, ''da bollox of speakers'' - rog mogale people say that about class d and skytech! 3) he was asking what model of B&C's, not you repeating B&C when he knew it was some sort of B&C |
Posted By: adambomb
Date Posted: 21 May 2007 at 11:31am
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£70... yup I reckon I could get that made for that.. easy... if your paying more, pm me.
As Ginger said "the bollox" isn't really an acurate description is it... anything sensible to add?
Again, as Ginger said... which B&C models exactly?
By Splay angle I ment, how are the boxes to be positioned after assembly... surely there will be a correct angle to splay them at (I would like to build this into my cabs so I would need to know before building).
Also "waveguide" is a bit of a loose term init? How effecient are these horns with the correct drivers?
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Posted By: mykey
Date Posted: 21 May 2007 at 12:25pm
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adambomb!
25kg of resin in the Uk 5 years ago was 65 pound
the 12'' horn on its own weighs 22kg
so lets say 2 thirds of that is resin
plus the 2'' horn
plus the bracket, thats going to cost atleast 25 quid
do i have to work it out for you?
don't be a plank and tell me you could get all three made for 70 quid.
adambomb is that you in the pic?
 ------------- ......just all them hanging there like giant bananas. |
Posted By: gingerbiscuit69
Date Posted: 21 May 2007 at 12:34pm
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maybe thats what it costs you, but going to a local company who deals with this kind of thing in bulk, is nice and cheap.
dont be immature over this, he is a clever guy! he is merely asking questions about your product, which you arnt making any effort to answer ... great business plan! |
Posted By: mykey
Date Posted: 21 May 2007 at 12:43pm
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65 pound was bulk buy (trade) 5 years ago
and I was one of those local company's Mr Tango
if he was a clever guy why don't he supply all of us with his magic horn's, and we can all live happily ever after? ------------- ......just all them hanging there like giant bananas. |
Posted By: adambomb
Date Posted: 21 May 2007 at 12:47pm
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All I can say is... Your getting fleeced!
I had a,loong chat with a local fibreglass manufacturer... and it ain't that expensive! So yea.. I reckon I could, if I so wished, get a batch of a similer design made for around the £70 mark... (obviously the more I make the cheaper it gets)
Small bit's of bent metal don't cost £25... you can buy the HF horns on ebay.. for bugger all...
I'm not being a plank... I'm looking at the product and estimating the costs involved... which are not for off £70ish.. maybe a touch more.
You shouldn't be ashamed of making a profit.. or try to hide it.. that's why your in business... that's why I'm in business... not doing it for my health (that's for sure!)...
So... Still no answers to the (fairly basic) questions Mykey... your sales pitch NEEDS WORK! (little hint : don't be rude to potential customers!).
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Posted By: adambomb
Date Posted: 21 May 2007 at 12:48pm
| And yea.. that's me on a good hair day. |
Posted By: mykey
Date Posted: 21 May 2007 at 12:59pm
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i'll get dansound to give you a call, he's paying through the nose and the bracket isn't a small piece of metal, you need to go and see the item in question to see what's involved infact you can go and get one and take it to your guy and ask him if he can build it for 70 quid I'm sure he will do an impression of the laughing policeman
if you guy's were my potential customer's, my food would be used soggy PG tip's T-bags left over from one of your commercial's
all jokes aside, if you can don't pay up front because i dont now how they can do it for that price
mine are 8mm thick plus 12mm ply wood reinforced ------------- ......just all them hanging there like giant bananas. |
Posted By: adambomb
Date Posted: 21 May 2007 at 1:13pm
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Ho Hum... Still no answers... suprise suprise! (why is it you do this EVERY time your selling something??).
If your potential customers arn't on this site...Who are your customers then mykey? The market for home brew speaker cabs ain't that huge... (and it's not like your horns are used in any commecialy available cabs is it?!?!)
This has got to be one of the best places to promote your products... if you treat us like fools.. your a fool to yourself.
Get Dansound to call me.. I would be glad to help!
Anyways.. enough of this...can we get back to the topic... can anyone give me any clues on hornresp... I know i got some of the figures right.. but not all.. hints please!! (I am trying to learn the thing.. but it's not very user friendly).
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Posted By: mykey
Date Posted: 21 May 2007 at 1:20pm
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250 million indonesian people ------------- ......just all them hanging there like giant bananas. |
Posted By: adambomb
Date Posted: 21 May 2007 at 1:22pm
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Still no answers. |
Posted By: mykey
Date Posted: 21 May 2007 at 1:24pm
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you can't get away with it adambomb, you said you can get them made for 70 quid easy
that was your statement
danny's going to place an order with you magic man ------------- ......just all them hanging there like giant bananas. |
Posted By: adambomb
Date Posted: 21 May 2007 at 1:24pm
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ahh yes.. that well known speaker manufacturer "indonesian people"... should have known.. stupid me. |
Posted By: adambomb
Date Posted: 21 May 2007 at 1:25pm
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I can.. waiting for the call! |
Posted By: discosucks
Date Posted: 05 May 2012 at 10:58am
| any idea can these moulds still be got or is there alternative for some somewhere in the same price range? cant even find a web page for jan audio any more. |
Posted By: tamuks
Date Posted: 29 May 2012 at 6:58am
| what you are talking about aint easy at all guys ask me lm still fabricating mine |