Extended Range Cabinet. DIY build. And other questions....

DIY and you only need to go down to B? Look up TL-606 plans, and drop in a Peavey 1505-8dt, Eminence 3015, Faital Pro 15PR400, or EVM Pro 15B.

Those response values are of only so much (very little) use. You need to consider the design of the cab as a whole to know what kind of performance you are looking at.

 

Why don't you just build a fearful 15/6/1? Plans are free. I have been reading heaps of threads, reviews, watching videos and gave finally decided I'm building a 12/6/1, and another one later next year. Those 2 and my little shuttle 6.0 and I think I'll be set. My 2 cents

 

Just curious. What frequency do you think that is?

Lots of different software out there, some free, some not. You will have to do some research on which program you feel comfortable trusting.

 

Flameworker, you have kindled a fire which has gone out.

Low B fundamental takes a huge amount of power and driver excursion to produce on a level that is worthwhile next to an unamplified drumset.

So think again.

 

OP....you remind me of me! I'm often dissatisfied with commercial 'me too' designs that follow the herd, and this often convinces me that I need 'a better mousetrap' and that I'm capable of designing something that meets my unique needs.

Usually, a small amount of research shows that, unsurprisingly, in a big wide world there are hundreds if not tens of thousnads of people who have identified the same 'unique' criteria and, furthermore, there are tens of those people who have theoretical and practical audio engineering skills that have taken a lifetime to perfect. These turn out to be the people who have already devoted thousands of hours of planning, experimentation and prototyping to achieve the design goals that I had convinced myself I was alone in trying to resolve.

My dissatisfaction with the status quo and my attempts to build myself something better are not a bad thing, they teach me a great deal in the process and I've ended up with a Barefaced 15/6 design for my bass cab, Bill Fitzmaurice Jack 12 Lites for PA and Bill Fitzmaurice Wedgehorn 8s for floor monitors, all of which give me better performance for my needs than the ubiquitous commercial offerings and have educated me in the process of choosing and building those systems.

I'm starting from the same place as you, except that rather than starting from spec sheets of individual components where I barely understand the complexity and interaction of Thiele Small parameters, I'm starting with the credentials and reputation of knowledgeable people who have trodden the road I want to go down and built that roadway for me.

 

+1. I have a BFM Omni 15, and it's even better than Barefaced or fearful 15/6. But most of the time I don't use it, because its more than I need. My daily go to cab is a BFM Jack 12. Both are better than any store bought cabs. I've learned a lot about speakers in the last ten years, enough that I could design my own. But when I can take advantage of the skills of a guy whose been designing cabs since Entwhistle played with the Who at Woodstock and really has forgotten more about speakers than I'll ever learn why bother?

 

I'll wait for input from others but I think 160 watts isn't enough power for a loud low B. Just digging around the Internet I found a Wikipedia entry talking about sound reproduction and it seems like they were talking more about stereos rather than instrument amplification.

For most audio applications more power is needed at low frequencies. This requires a high-power amplifier for low frequencies (e.g., 200 watts for 20–200 Hz band), lower power amplifier for the midrange (e.g., 50 watts for 200 to 1000 Hz), and even less the high end (e.g. 5 watts for 1000–20000 Hz). Proper design of a bi/tri amplifier system requires a study of driver (speaker) frequency response and sensitivities to determine optimal crossover frequencies and power amplifier powers.​

So 50 watt mids vs 200 watts for lows. i have never used tube amps and maybe they have way more headroom than the current class d amps but I'd still be worried that 160 watts might be 1/10 of the power you might need for high volume fundamental B. 31 Hz is way low and seems it would take a mountain of power. See if you can get TS parameters for that 18 and start running various cabinet sizes and ports. Se how many dB down you'll be at 31 Hz. Jooles4001 makes a really good point About designing new speakers vs using plans by audio experts. From a learning exercise it would be tremendous. It may or may not be practical.

 

It's enough if you have a high efficiency speaker. With store bought you don't really know, because no one publishes charts that tell you exactly how many dBs you get out per watt in at every frequency. Most DIY designs do have charts, and if you have questions chances are you can get the answers straight from the designer. A 3dB increase in efficiency is the same as doubling your watts, so if you don't have a big amp a more efficient speaker can make all the difference. Look at the Omni 15 chart compared to a 4x10 on this page, the difference at 40 hz is 6dB, that makes a 160 watt amp as loud as 640 watts into the 4x10. The reason I don't bother lugging my Omni 15 to most gigs is that is goes a lot louder than I need, and I can get away with the much smaller Jack 12 instead. When I play in the streets of Montreal during Jazz Festival with no PA my Omni comes out of hibernation, and it never fails to deliver over a whole city block.
http://www.billfitzmaurice.com/Omni15.html

 

Thank you. Yes that makes a lot of sense. I wonder what the sensitivity of the 18 he mentioned is at 31 Hz. Obviously depends on the cabinet design but I wonder how flat a response you can get down to 31Hz and how much power that would take. Thanks.

 

@flameworker, you are either a very fast DIYer, or spend too much time researching the wrong things.

I don't mean to offend you, as many of the questions and ideas that you have I can relate to.

Finally, instead of asking so many random questions (as you seem to have lots of random posts), I decided to do some research. Join forums such as Bill Fitzmaurice and Greenboy, and read as much as possible. You will learn a lot about lots of things, but mainly you will find the results of experiments that others have already done, which will help you save a lot of time, and even more money.

Obviously there is always the possibility that you could invent the holy grail, but if you learn what doesn't work first, then you can spend more time on things that may well be good.

(IMO, IMHO, YMMV etc. etc.)

 

Flameworker, before you even start a DIY build please understand that it is not a cheap road to follow. Done properly a home brew will cost way more than you can buy a commercial speaker cabinet for. It also takes a lot of work and a lot of love to make it right. In your place I would look at the fEARful plans as these have all the details already optimized.

I use Acme speaker cabinets and they do handle a Low B at power. To do this, as they have to obey the laws of Physics, they are inefficient. I am feeding each of my 2x10s with up to 500W. Whatever route you eventually follow it should include replacing your amplifier with something more hefty. To get a Low B loud you require power. If you don't have that power anything else you do is wasted effort.

 

Please take this constructively: It is evident reading your post that you are quite a ways from being knowledgeable enough to undertake the design being attempted. You have obviously done some substantial research, but your goal of low B fundamental reproduction is extremely ambitious. There are very few commercial designs that succeed at reproducing deep fundamentals at giggable sound pressure levels. The only cabs capable of low B fundamentals (and that are portable) to my knowledge are those of the Acme line. They achieve this in a reasonable cab size by trading off some efficiency. For high spl gigs you will need multiple cabs and a high power amp.

With respect to the low end capabilities of 15 and 18 inch drivers, most pro 15's are good 50-60 Hz drivers, while 18's are typically good 40-50 Hz drivers. In general, do not pay attention to the frequency response spec (like 20-3000 Hz) when trying to evaluate the low bass capability of a driver. You need a combination of Fs, Qts, Vas, sensitivity and Xmax, and a knowledge of how these interact in order to just get a start. You will need this information and understanding in order to use loudspeaker design software (like winisd) effectively.

As others have pointed out, the power, cab size and driver requirements for achieving usable low B fundamental reproduction are formidable, and generally impractical. You would be well off to aim for solid 60 Hz response and to rely on the 2nd harmonic below that. Most of the better commercial cabs take this approach. They take advantage of the brains ability to fill in the fundamental based on the reproduced harmonics.

If you want to learn this stuff, try starting with a relatively simple design. If your goal is simply to acquire a cab that will reproduce the low B fundamental, consider just purchasing a cab (or cabs). In between, consider building a high quality readily available design like one of the fEARfuls. Most players have never experienced this level of performance. If you have not heard one, you owe it to yourself to audition one before attempting something more ambitious.

 

Works just fine producing a low B loudly.

 

The 3015LF is ververy different than the 3015 or the kappapro.

 

If you learn nothing else here, learn that swapping drivers is almost never a good idea with a well thought out design. The design is based around the driver.

If you can learn two things, learn that the fundamental is not nearly as important as you think it is. If you want to move on up to a Bi-Amped rig with basshorns, feel free, but they are inconvenient and really not needed to get the job done.Save it for when you have roadies and a tractor trailer to carry them in, if that happens. Not having them won't be what limits your career.