T24 as a "kick bin" above T60?

[subconsciousnz]

Hey there

I have a friend building 8x T60s as an outdoor party / bass music rig. We are wanting to have a four way system for cleaner low low extension and better low mid transient response also (take some of weight off the tops). In looking for options which wouldn't provide too much difficulty with potential phase issues, I looked at the T24 design and response.

Since it gets most responsive around 80Hz and looks solid up to 200, I figured it could work reasonably well, since it's also a similar design.

Wondering a few things. If anyone else has done this or if there's any obvious reason this is a dumb idea.

I note the suggested driver (Eminence BP102) has a stated usable frequency range of 40Hz - 2k, so I'm curious how the T24 would go above 200Hz (say we wanted to cover 2 octaves 80 > 320 with it)? Tbh it's more likely it would only cover 80 - 160 anyway, but just wondering about the usable range of this box.

If it's a reasonable idea, how many T24s would be needed to keep up with 8x T60s (assuming X of 30 - 80 & 80 - 160).

If it's a dumb idea, any links / suggestions of a more suitable design for the purpose would be awesome!

Any response greatly appreciated

[Bill Fitzmaurice]

There's no advantage to a four way system. Kick bins are a relic best left in the '90s.

[Tom Smit]

Phase problems occur when using more than one type of sub-woofer. Let the T60s take care of the bottom end, right up to around 100hz. Then, let the tops take over. Any of Bill's designs for the tops will work. What tops were you planning on using?

[subconsciousnz]

Appreciate the responses.

I guess my thinking with having 8x T60s is that we could run them in a solid line (all coupled kinda thing) across the bottom, with some secondary sub speakers atop those, since having 2 stacks of 4x T60s in stereo would potentially create some phase pockets in itself. Though of course the "kicks" would be in a "stereo" config (i.e. with a gap in the middle).

Our builder isn't super keen to take on the more complex build of the BFM top designs (as it's trickier but he's also just super busy). Also we are all the over in New Zealand so ordering the kits (to avoid the more difficult elements of the top build) may be unrealistic in terms of shipping.

The buyer is keen on going all out price wise and getting something like F1 or Void for the tops (which I'm currently trying to talk him out of as there's not even a distributor here (order from Australia) and I think they're ridiculously over priced). However, really the only brands widely available here are stuff like QSC, JBL, Mackie etc. Vast majority is active these days too, which for an outdoor rig isn't ideal (dust and potential rain, even with some cover isn't my idea of smart).

I'm quite aware of the amount of power we'll be asking from the tops running 8 T60s underneath (which is another reason I was thinking splitting the load a bit would be a good idea).

Am I right in saying that you sell your all your speakers as flat packed kits that just require assembly? Can I ask, have you ever shipped internationally? If we were to look at ordering from you (which I do like the idea of in terms of having a nicely matched set up), what would you suggest top wise to match the T60s, and for amps? For all manner of bass music (trance, drum n bass etc), likely almost no live music. If I can go back to my guy with a ball park figure he might be keen on it.

Thanks for your time.

[subconsciousnz]

Apologies, should do my own reading on your page first.

I see the DR300 and Omni15 is the likely best candidates of your designs, to top our rig. I note that the Omni says it is a much easier build. Am wondering how it compares performance wise to the DR?

The numbers questions (how many tops required) are answered clearly on the speaker pages already, cheers.

[Grant Bunter]

G'day from across the ditch, and welcome to the forum

Quite apart from Bill's statement about kick bins in general, I'm not sure T24's would keep up anyway!

I've built 4 x DR250's, and one dry hirer (using the pair with the melded array) I have had said they were as good as, if not better than F1 in his opinion.
Then I told him what they cost me to build. He was astounded.

You don't need to do DR's though, if you don't (or your builder doesn't) think you're up for it.
Look at the Otop12's or 15's, simpler build (though still have some angles to get your heads around), slightly lower performance and they sit flat for easy stacking.
Fine from 100Hz up from what I've been told.

Unfortunately for you, the NZ/AU authorised builder has retired.
Bill's flat packs are third party, the best source would be from Leland (who's a forum member) at Speakerhardware.com.
I can tell you right now shipping, due to Covid, will be a killer.
In scales of economy, you could totally mess up a heap of sheets of ply, and still be better off $ wise, sourcing and building at home, in comparison to shipping flat packs in and waiting for ages.

Amp suggestions come after you've decided what drivers you're going to put in to the T60's, and taken into account in cab and ex cab wiring for impedance load manipulation.
The reason I say this a single lab15 loaded cab will be outperformed by a dual lab12 loaded cab.

Like Australia, Eminence at reasonable prices is difficult at home, but again, shipping is way up at the moment, so have a look at local pricing and do some sums to compare buying from the US and shipping.

Let me know if I can help out with sourcing stuff like Duratex from Australia.
PL premium might be best shipped from the US, say a couple of boxes. There isn't anything like it I've found so far in the antipodes, and believe me, I've looked. It's the go to adhesive, that expands to fill gaps.
I'm unsure if the source for PL in NZ (tips techniques suppliers sub forum) is current, but PL is no longer on sale in Australia thanks to the Masters group falling over and Henckel saying "gone"...

[subconsciousnz]

Hey Grant, cheers for all that

Yeah the price of getting Funktions over here is just astronomical. And while I do think they're beautiful sounding speakers, I'm not convinced they're 10 times better to reflect the price.

Just had a chat to our builder who says he is probably comfortable to build the DR300s (was more a time constraint than a skill one, but he's excited about it now so), but we are going to buy both sets of plans (for the Omni15 and the DR300) so he can make an educated decision about that.

In terms of the T60, we are building the single LAB15 design. We already have a bunch of those drivers from a previous build, so decision is already made there.

In terms of additional parts we might require, have a few people working in the industry able to help with ordering (and include extra parts on orders that are already coming in etc).

As our builder has access to a some pretty good kit (a CNC router big enough) he is adamant that doing rebated joins (rather than adhesive only) should be stronger / better, curious if anyone has any feedback on that. Makes sense to me.

Amp recommends welcome

[subconsciousnz]

Also I note that the DR300 says it is better where there will be a bit of distance between the speaker and closest audience member. Due to the nature of the outdoor festival "experience", people may be a bit closer, so I'm wondering whether the Otop15 would be a better choice in our case (I know what powerful tweeter arrays can feel like if you get too close )

[Grant Bunter]

Yep.
The DR300 is a concert top.
At pretty much every concert, the audience is more than 10m from the cabs. The DR300 is designed with that in mind.
So, if you want people in close (or they want to be in close) then maybe the Otops are a better choice, with the bottom pair having a melded piezo array, for very wide horizontal dispersion.

It's not so much about being near powerful tweeter arrays, cause that's quite evident close up and in front, but more about when you're off axis to the cabs.

There's great builders everywhere. Not a lot of them have built speaker cabs other than simple boxes (eg direct radiators) though.
Because this is DIY, it's essential the plans are followed to the letter to get the performance from the cabs you might expect having read the sales page info.
CNC router and rebated tab joints are all good! The PL premium is not just about being a great adhesive. It also creates leak free joints (and the plans tell you how to check for leaks), and that is absolutely critical in the design, especially the subs. Leaks = loss of performance, and some leaks are extremely difficult to fix after you've built the cab, so the best thing to do is make it leakproof as you build it...

[Bill Fitzmaurice]

As our builder has access to a some pretty good kit (a CNC router big enough) he is adamant that doing rebated joins (rather than adhesive only) should be stronger / better, curious if anyone has any feedback on that.

Rule #1: Follow the plans
Rule #2: Never break Rule #1. If your builder was an expert in the field of loudspeakers you'd be building from his plans. Some of the best results have come from first time builders who followed the plans to a 'T'. Some of the worst have come from experienced woodworkers who did it their own way. A speaker isn't a table, or a chair.

[subconsciousnz]

Hey just a follow up question.

My friends are going ahead with their T60s and are going to build a stack of DR250s on top. 4 with a melded piezo array and 2 with a flat array, Deltalite 2510s.

They've mapped the T60s into their CNC software and it's looking very tidy (exciting). However, they decided it's a good idea to leave a hole in the side of the bin, because they would prefer cable access there:

Both sides of that otherwise sealed chamber which isn't a part of the horn path (meaning a hole right through).. I told them I think this is a really dumb idea as it will change resonances and perhaps even pressure.

I know I was told to "follow the plan to a T", which I respect! I'm not the one doing the build or funding it though, merely consulting. Curious on how this would affect the performance of the bin and why, hoping I can talk them out of this decision as I'm concerned at worst it could alter the pressure or resonance of the bin and change it's power handling? Perhaps I'm wrong though

[Bill Fitzmaurice]

That is an option, along with putting the Speakon connectors inside that chamber to prevent people from tripping on them. It's in the plans and is shown in two of the Sketchup models.

[subconsciousnz]

That is an option, along with putting the Speakon connectors inside that chamber to prevent people from tripping on them. It's in the plans and is shown in two of the Sketchup models.

OK great, thanks very much for your response!

[Titanium Hand]

hey subconciousnz how did you get on mate? You blowing the kiwis minds with those T60's yet? Im in AUS Built T39s, OTOP12 & T60's for the bass heavy music that was being produced in the great EDM DUBSTEP brostep rise to fame back in 2012. Ive been to festivals and nightclubs all over Europe Since, London, Paris, Berlin, Amsterdam and the Czech republic. Ive not heard anything else like this BFM Gear with a comparable number of cabs. Ive been busy adulting probably this last 5 years so never on here. My cabs have seen loads of work getting thrashed by young blokes with heeled parents for 18ths, 21sts, 30ths, Doofs, Engagement Parties, Christmas Parties, New years Eve Parties and a few weddings. Ive just hired them out most of the time as Im too busy. Any time I get the chance to get them out I do, and if its been 3 months or 3 years theyve never missed a beat. Building the cabs I tackled was easy. They still look great. People always try to buy them off me. Chances are When I die Ill be pushed out to sea on a barge of my lashed up BFM cabs and set alight! They are literally that great. Im fast approaching 40 now and my time in the music scene has all but gone, business has taken me in other directions. But my love for Filthy German Techno has remained. These BFM Cabs are the real deal. My advice to anybody thinking of having a go, is to do it. Dont hold back just make it happen youll never regret it. Best of luck

[Grey Owl]

Gidday Sport,
First haere mai and welcome to BfM.
1. Follow the plans to the letter, in word and spirit. Any arcane questions, ask the oracles on here. We've all been there before.
2. Don't let commercial builders rush where angels fear to tread. Keep them on a tight leash from running away out of control. Don't second guess the plans without asking first. There's a tremendous depth sitting quietly on this Forum watching every move who will generally assist anyone who finds themselves in schstum.
3. Take photocopies of the plans.
4. 2 days later after each has read the plans slowly 3 times n made notes with a red pen, get them all in 1 room (no beers to be provided) to each give their take on what the plans say.
5. No shouting allowed!
6. I use expanding urethane construction Gorilla Grip available in New Zealand. Seems to work well.Don't buy the 30 minute hard grab stuff; ends in tears. Sticks like s..t to the hairs of a mongrel dogs arse but, follow Bill's warnings in the plans! Urethane is very messy n frustrating stuff if you don't read the plans.
7. Duratex is available in Enzed now from John at Livesound. It's horrenously expensive but it does exactly what it says - top shelf result. He's also the Eminence Agent for NZ.
Look forward to seeing the results of all your efforts; it will be worth it.
Cheers