TH-18 Flat to 35hz! (Xoc1's design)

What about the THAM12 like TH and the corrections

Hi all,

I don't know what happened to this thread, but it seems to have frozen...

I wonder if the corrections as suggested by some of you also would work for the TH that have the speaker at the bottom, like the THAM 12 and TH-mini.

I did try the THAM12 at first, but missed some low end, so I extended it and came up with a slightly bigger version. Also, I changed the first part of the TH to start smaller.

Would the correction for pressure work as drawn in the picture I've added (the orange bit where the speaker is fire-ing into the first segment of the horn.

Suggestions, comments, corrections?

kind regards,

Frans

I did do a first test with this version WITHOUT the correction, sounded pretty massive compared to the THAM12. Also made a version with the volume corrections (2 discs with the size and shape of the cone). No real difference testing by just listening in an A - B test.
 

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MRGSR did you ever get to compare the Pal12 and TH18?

I don't know if the guy in Perth ever built his TH18 but I can get Beyma and 18 Sounds for about the same price as the woofers on USSpeakers including shipping. I am not a dealer. I just order a lot of speakers. I usually order 18 Sound drivers most of the time.
 
Good day to all. I'm sorry for asking this question here but these tops were suggested to go with the TH18.
I have built two of the JBELL 12 tops and need to know a few things before ordering the equipment to go with them.
Firstly is there a better top recomended for the TH18?
Second the equipment t I am about to order is as follows:
Dayton audio PA310-8-12 woofer rated at watts
Selenium D220TI-16 tweeter
Gold wood GM500PB waveguide
Is this a good combination or is there a better combination recomended for these tops?
I am looking at the following also
a two way crossover with 12db/oct with 3000hz crossover point rated for 600watts
A two way crossover with 12db/oct with 3500hz crossover point rated for 500 watts
I will be using a driverack PA+ In my setup now and will be removing the active crossover. Will I need to use the passive crossovers In these cabs or will the drive rack be a better balance for the sound?
Thanks to anyone with some assistance with these questions. I want to order the equipment by Wednesday.
 
1)I have built two of the JBELL 12 tops and need to know a few things before ordering the equipment to go with them.
Firstly is there a better top recomended for the TH18?
2)Second the equipment t I am about to order is as follows:
Dayton audio PA310-8-12 woofer rated at watts
Selenium D220TI-16 tweeter
Gold wood GM500PB waveguide
Is this a good combination or is there a better combination recomended for these tops?
3)I am looking at the following also
a two way crossover with 12db/oct with 3000hz crossover point rated for 600watts
A two way crossover with 12db/oct with 3500hz crossover point rated for 500 watts
4)I will be using a driverack PA+ In my setup now and will be removing the active crossover. Will I need to use the passive crossovers In these cabs or will the drive rack be a better balance for the sound?
Thanks to anyone with some assistance with these questions. I want to order the equipment by Wednesday.
1)If you don't use the components Jbell advised, the cabinets won't work as they were designed. There are certainly better top cabinets, but they likely are not within your budget, so no reason to discuss even more off-topic pursuits here.
2) Are these components what Jbel used, if not, why did you choose them?
Without some definition of "better" (louder, matched dispersion, more power handling, whatever) the question can't be answered.
3) 3000 and 3500 is quite high for 12" speakers.
Passive crossovers need to be designed for specific drivers, their impedance, sensitivity, and physical location relationship.
To design for those parameters is not trivial, generic crossovers simply won't work well, and may not even properly protect the Hf driver.
4)Active crossovers are far easier to set up properly than passive, and 24 dB slopes allow for a lower crossover with less excursion than 12 dB slopes, and less overlap, so if not aligned properly at least the "damage" is limited to 1/2 octave or so.
Be aware the Driverack PA+ reverses polarity on the midrange output, not mentioned in the manual..
Have fun,
Good Luck!

Art
 
Thank you for the information. I will find the page from the JBELL discussion and post it here so you can see what was recomended and these were some of the components recomended.
As for the driverack reversing polarity output for the midrange output what am I supposed to do with this? Do I just REWIRE the speakon connector for the speaker cable or do I REWIRE the the entire cabinet with reverse polarity. I'm very new to this stuff and most of what I read I don't quite understand especially with db slopes and crossover points etc... I will try my best to keep up and I am a fast learner and don't mind reading.
 
PER JBELL


There was no HS12 thread that I'm aware of, just tidbits here and there.
The Hs12 did use a CD and horn. I've gathered up some bits of info I found in no particular order and placed some pics and drawings at the bottom of this reply.

Per Jbell
"I don't really have a thread on any of my tops. They are just dime-a-dozen kind of design... They key on these is to find the right driver to make a horn/ported cabinet work. Once you find the driver, you have to play with hornresp for awhile to get a nice flat response in 4pi. (tops don't sit on the ground, so response curves tested that way are bogus in my mind)

Here's the best pic to show how my tops are built. The horn 'plates' are 13" long, and 45 degree angles on each end. It was designed to use partsexpress 15x22 metal speaker grills. I just bolt a 12" dayton waveguide to the metal grill and use a 16ohm selenium crossed at 2k. It uses an eminence beta 12a-2, and ports are tuned to 95hz. (sorry, not a fan of the cheap eminence compression driver....)

22x15 grill
try delta pro 12a
selenium 220ti-16 80w/40w
Goldwood GM-500PB
better-
Dayton Audio PA310-8
Selenium D2500Ti-Nd-16

I've had a couple questions about the HS12 tops that I've been using with the SS15 subs. The name HS12 is 'half sheet' 12" driver tops, as I can get a pair of them (barely) out of a single sheet of ply.

Attached are a couple pics, and any enterprising person can from these, reproduce my tops. I personally use eminence beta 12a-2's with selenium 16ohm 220i compression drivers. I use a simple 12db/oct 1900hz crossover with high C=2.6uf, L=2.68mh and low C=5.24, L=1.34mh. (at least that's the values the crossover calculator gave me.) I used parts express components that were as close to that as possible, the high capacitor needs to be a poly, and the high inductor needs to be air core, electrolytic and iron core is ok for woofer. If you are going to stack, the goldwood gm-500pb horn works, and for single cabinets I've used the dayton h12rw 12" conical waveguide. In both cases I just bolt the horn to the metal grill. The PE square hole grill is very strong and is actually what I designed this cabinet around.

Ports on the sides create feedback. Ports deep in the horn sound funky...
The baffle with the small 'fill' plates is easier/faster
The cabinet size is designed for a PE metal grill / and horn lens bolts to grill. (only use the square hole grill, round hole PE grill is too flimsy)
The horn is a low pass, and the eminence typical 'rising response' counteracts that. (horn low pass keeps you from having to eq out the midrange 'honk')
Any cabinet not 'midbass heavy' in 2pi sounds weak in 4pi (on stands) so yes, this is kinda a 'midbass heavy' design. You can see how even in single cabinet, this design is strong to 100hz.
A selenium 220ti-16 80w/40w sounds MUCH better than an ads1001
16ohm selenium matches up to the 8 ohm beta12a-2 almost perfectly, no resistors needed in crossover.
VERY LITTLE eq needed when used with the dayton 12" waveguide, and a nice open, non honky sound comes from compression driver.
1.9khz crossover means no 'fillers' needed, no need to get 12" to run up to 3.5k (selenium can go down to 1.5khz if needed)
95hz port tuning means this cabinet is good xmax down to 60hz if you 'have' to run no subs, and is strong down through 100hz. (which is important for male vocals)

So you're running a single Beta 12A-2 with the Selenium? I'm curious, because the Selenium is listed as 109dB / 2.83V (which is 0.5W into 16O), whereas the Eminence sims as 103dB in your horn.

Is it no problem for the amp to run a speaker with 8O woofer and 16O tweeter?

I read earlier you were using the Goldwood GM-500PB, now you mention a Dayton... is this one better?

This looks like an interesting top, if it can hit 123dB at 100W and can be built for under 200 bucks.
__________________
After that, I'd go selenium and goldwood if you are going to stack otops, or dayton waveguide if you are not. Both the goldwood and dayton benefit from a triangle shaped 'reflector' of sorts vertically in the middle of the horn to avoid a HF 'hotspot' when directly on axis.



You are right on the money on the selenium at 109 for the 8ohm, go to 16ohm and you are -6db..... perfect match for a 103db woofer section. Impedance swings wildly within frequency range of a speaker -- amp has no issues with it. I would still consider this a nominal 8 ohm cabinet.

Either horn works well, it's a matter of if you want to stack them or not. If you run the goldwood turned 90 degrees from 'normal' they do seem to integrate a little better than a stack of cabinets using the dayton waveguide. I also like the sound of the dayton waveguide a bit more. It has less overall gain, and a less 'honky' sound than the goldwood. If you use the goldwood, you actually need to eq it down just a bit, It's a bit on the bright side straight on. It's really a good 'long throw' option.

So horn choice is up to how you are going to use them. For me personally, I use the dayton in most of my applications. (where I'm running a single cabinet per side and 1 or 2 SS15 subs)

SS15 is good for 63v (500watts) and HS12 with the beta12a-2 top is good for 37v(180watts)
GC note... try delta pro 12a for high output

Originally Posted by k parker
Hi there i have been looking at this and other treads for a while now,i have fall in lov the SS15 [i have pic of SS15]and HS12, i have suggestion for the HS12 were the components is concern the Selenium D2500Ti has a better sound than D220Ti and what about the B&C ME10 H90+V60 horn it seems to have very good dispersion and the Kappa lite 3012HO for a over all higher output enclosure (just my two cents)

Hey, thanks for the thoughts. The hs12 components were chosen primarily for cost reasons, and yes there are many good upgrades that work well in that cabinet.

The dayton pa310 driver is a great upgrade and provides more 80-100hz that the beta12a-2, and gives basically the same power handling as the 3012ho at half the price.

Yes the neo 2500ti sounds better in the typical 40x90 horn than the 220ti, but the low expansion dayton waveguide seems to mitigate that. The 220ti/dayton is a reasonably nice sound.

This being said, my 'upgraded' drivers that I like for the HS12 are the pa310/2500ti. (keeping in mind the 2500ti is a bit louder than the 220ti)

If you want to make these cabinets lighter DL2512/2500ti puts it on about a 6.5lb diet.
SS15 is good for 63v (500watts) and HS12 with the beta12a-2 top is good for 37v(180watts) Your kappa+psd tops (if you build them) would be good for about 49v(300watts)
Ben, you are on the money on the design. Yes, I started with an OT12 style cabinet and fixed the things I didn't like.

Ports on the sides create feedback. Ports deep in the horn sound funky...
The baffle with the small 'fill' plates is easier/faster
The cabinet size is designed for a PE metal grill / and horn lens bolts to grill. (only use the square hole grill, round hole PE grill is too flimsy)
The horn is a low pass, and the eminence typical 'rising response' counteracts that. (horn low pass keeps you from having to eq out the midrange 'honk')
Any cabinet not 'midbass heavy' in 2pi sounds weak in 4pi (on stands) so yes, this is kinda a 'midbass heavy' design. You can see how even in single cabinet, this design is strong to 100hz.
A selenium 220 sounds MUCH better than an ads1001
16ohm selenium matches up to the 8 ohm beta12a-2 almost perfectly, no resistors needed in crossover.
VERY LITTLE eq needed when used with the dayton 12" waveguide, and a nice open, non honky sound comes from compression driver.
1.9khz crossover means no 'fillers' needed, no need to get 12" to run up to 3.5k (selenium can go down to 1.5khz if needed)
95hz port tuning means this cabinet is good xmax down to 60hz if you 'have' to run no subs, and is strong down through 100hz. (which is important for male vocals)
 
After reading this do you think I should use the drive rack or try to find 1900hz crossovers?
I think you should read this:

http://www.diyaudio.com/forums/mult...designing-crossovers-without-measurement.html

As far as the inverted mid polarity on the Driverack Pa +, some crossover settings will require reversed polarity to be in phase.

I would not rewire the speaker cables to reverse polarity, that could cause confusion.
The polarity of the mid and high should be corrected in the cabinet.

The mid and high outputs will need around 7-9 ms delay to compensate for the TH path length. Since you have decided on a bass reflex (phase inversion) top cabinet, and have not stated what way your tapped horn is wired, there is a 50/50 chance that an inverted mid output will be correct for the low to mid crossover, and since you have not decided on the high crossover, that is also a crap shoot.

Copying cabinet designs is the easy part, aligning a multi-way system is more difficult, and requires some measurement to "get it right".

In addition to the sticky above, research "phase", "polarity", "time alignment" and you will start to understand the difficulties.

Since this is all pretty off topic for this thread, I'd suggest starting your own in the multi-way portion of DIY when you are up to speed on the concepts, and understand why you can't just "find 1900hz crossovers" that will be correct for a custom application.

Since you are "a fast learner and don't mind reading" within 40 hours (or so) of study you should start getting it :) .

Let the Fun Begin!

Art
 
lol i better get started then.
the tapped horn is wired direct from the speakon connector on the back of the cabinet directly to the driver, with no passive crossover, or anything else added, is this alright or would i need to change or add something here as well?
thank you very much for the suggested research topics. i will start reading tonight then see where i go from there. i dont think i will order anything until i get a better understanding of everything you have told me especially reversal of polarity to get the proper phase from the mids.
thank you once again and any further advise would be greatly appreciated, i will start a new thread tonight also , i will make the topic 'understanding multiway system alignment"
 
l
the tapped horn is wired direct from the speakon connector on the back of the cabinet directly to the driver, with no passive crossover, or anything else added, is this alright or would i need to change or add something here as well?
Unless you want a passive crossover or EQ in the cabinet nothing would be added.
Positive voltage should make the cone go in to the horn throat, which is normally + to + or the red speaker terminal, except on some old JBL speakers which are reversed polarity from the rest of the industry.

Always good to check polarity on drivers, they can be mislabeled from the factory or re-cone shop.
 
Hi Pabesco,
Could I suggest you at least look at electronic crossovers they allow a spectrum of adjustments,slopes,delay,ect.and going with built crossovers is going to take a while to get right UNLESS you have them designed for your speakers,or use the correct speaker for that crossover.
With active you can almost built any top you want and adjust it with a crossover to tune it correctly,
Download a manual for a DCX2496 and read it,rane and dbx also make good units but are more costly, http://www.behringer.com/assets/DCX2496_P0036_M_EN.pdf
Many of the folks on this site and others helped steer me the right way ,pay attention as they have been there before and can save you time and money,NOT ment to be rude or critical just honest....OK!
GOOD LUCK with your build!!!!!!!!
Have you checked out some of Tom Danley's tops? many rave about them ,listen to them on you tube! Lots of other tops on there too.
Have fun I do!
NS
 
Hey thanks for the reply. I do have an active crossover that I just removed from my rack and replaced it with a driverack pa+ to balance the whole system. I know it would take care of the entire system with crossover, slope, delay, EQ etc...
I am learning how to use the new unit and will have to see where I go from there. If I need to use the electronic crossover again for the mids I will replace it in the rack and set it for the mids.
I am making notes of all of the sites and forums to read for more information and will get to them once iv read everything I can about the drive rack.
Thanks again