Midranges are always smaller than woofers - it helps to spread the midrange frequencies around more - it's called dispersion.
Bass frequencies need no help to spread around because of their long wavelengths - they diffract round the cabinet - how good is your Physics I wonder?
If the woofers are stacked vertically then the cabinet need not be wider than 16".
Lets not get into acoustic treatment of the room - that's a question too far at this stage.
Anyway, it's past my bedtime!
Bass frequencies need no help to spread around because of their long wavelengths - they diffract round the cabinet - how good is your Physics I wonder?
If the woofers are stacked vertically then the cabinet need not be wider than 16".
Lets not get into acoustic treatment of the room - that's a question too far at this stage.
Anyway, it's past my bedtime!
I have a VERY simple suggestion. It's basically the same as the kit I recommended earlier, but bigger, and 1/3 the cost...
Buy this pair of half-empty cabinets. They are only $100 each, and have many parts built in - horn & tweeter, crossover, handles, corners, carpet - that would probably cost $100 if you bought them all separately. This means the box itself is essentially free, and it ships for free (I assume you're in the continental USA).
Buy a reasonably good pair of 15" woofers - such as these ...and you'll be done.
It might not be perfect, but it will be big, loud, clear and robust.
It will be less error prone and might cost less than building from scratch with $20 drivers - especially once you add up the incidental costs (other than the drivers) of a big DIY box:
-plywood
-crossover
-paint
-wire
-glue
-screws
-handles
-sandpaper
-tools / tool blades
-delivery costs for all of the above
Each part of a DIY project might be cheap, but together they can easily go past $100.
If you wanted to personalise / "own" the project somewhat, you could download some (free) software, take measurements, and perform low cost modifications (e.g. stuff or modify the ports, add bracing to strengthen the cabinet) that can improve the sound. You can learn a lot by upgrading an existing box.
Then, as your funds & skills permit, DIY build additional bass boxes. If you build them to match the Seismic cabinets, you could have a system that resembles post 2 in this thread, which I think looks pretty good, in an industrial / utilitarian way.
The JBL 4691B in that picture is built similarly to the seismic cabinets - they are a basic box, with a crossover only for the horn. The woofer is hooked directly to the amplifier. They sound quite OK. As the owner (Zilch) commented in that thread:
"They are what they are, and damn good at it. JBL's still making equivalents according to the same formula."
Buy this pair of half-empty cabinets. They are only $100 each, and have many parts built in - horn & tweeter, crossover, handles, corners, carpet - that would probably cost $100 if you bought them all separately. This means the box itself is essentially free, and it ships for free (I assume you're in the continental USA).
Buy a reasonably good pair of 15" woofers - such as these ...and you'll be done.
It might not be perfect, but it will be big, loud, clear and robust.
It will be less error prone and might cost less than building from scratch with $20 drivers - especially once you add up the incidental costs (other than the drivers) of a big DIY box:
-plywood
-crossover
-paint
-wire
-glue
-screws
-handles
-sandpaper
-tools / tool blades
-delivery costs for all of the above
Each part of a DIY project might be cheap, but together they can easily go past $100.
If you wanted to personalise / "own" the project somewhat, you could download some (free) software, take measurements, and perform low cost modifications (e.g. stuff or modify the ports, add bracing to strengthen the cabinet) that can improve the sound. You can learn a lot by upgrading an existing box.
Then, as your funds & skills permit, DIY build additional bass boxes. If you build them to match the Seismic cabinets, you could have a system that resembles post 2 in this thread, which I think looks pretty good, in an industrial / utilitarian way.
The JBL 4691B in that picture is built similarly to the seismic cabinets - they are a basic box, with a crossover only for the horn. The woofer is hooked directly to the amplifier. They sound quite OK. As the owner (Zilch) commented in that thread:
"They are what they are, and damn good at it. JBL's still making equivalents according to the same formula."
Attachments
I really appreciate the time put into recommendation but If you have read some recent posts I am doing this for the extensive learning process and want to start from scratch
I am also going with more expensive drivers as you can see in recent posts (Eminence Delta series) having 2 12" woofers at 16 ohms each, 1 8" mid at 8 ohms, and Eminence APT-150 tweeter with the horn at 8 ohms. In October is my bday so I can get those and the $80 crossover then.
My current main concerns are with designing the enclosures but I do plan on building them myself. I still am yet to thoroughly look into the links already given to me but it will be hard to find articles that can be helpful to my application.
I am also going with more expensive drivers as you can see in recent posts (Eminence Delta series) having 2 12" woofers at 16 ohms each, 1 8" mid at 8 ohms, and Eminence APT-150 tweeter with the horn at 8 ohms. In October is my bday so I can get those and the $80 crossover then.
My current main concerns are with designing the enclosures but I do plan on building them myself. I still am yet to thoroughly look into the links already given to me but it will be hard to find articles that can be helpful to my application.
I would not recommend using more than one midrange driver per speaker. Midrange drivers produce frequencies with shorter wavelengths (than a bass driver) and when you place two midrange drivers producing these frequencies next to each other, they tend to cancel unless you are right in front of the speaker. This is not a good thing at all.
Moreover, you are designing a three-way speaker which means that the bass driver(s) will do most of the work, so there will be no need for additional midranges.
To give you an illustration of this, I build PA speakers that play over 130dB and there is certainly no need for 2 midranges in a 3-way system.
I also don't think you'll end up needing two 12" bass drivers - one should be plenty. However, having an unnecessary extra bass driver won't create any problems per se, it will just add cost and some complexity.
Regarding your point that 12" drivers will offer deeper bass, this is not necessarily true, particularly given you are looking at PA drivers which tend to be optimised for sensitivity and maximum SPL (volume), not for low-end extension.
How low do you want your bass to extend (in Hz), and what decibel level do you want the system to be capable of? These are the questions you need to answer before deciding what size and type of bass drivers you want to use.
Cheers,
Andreas
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I tried downloading some apps that measure Hz and have them listen to the lowest 808s and I got results ranging for 1 to 150 and it wasn't steady. I'm not sure what the lowest Hz is in rap/hip hop music but I would expect these DIY speakers to fill the room with more bass than my current studio monitors...
Also I am mainly looking for these to be able to play in my 13ft by 17ft room louder than my ears would want which I would expect with these larger drivers.
I know a lot of these choices for my application are unnecessary but as I stated in this thread the project isn't all about the most logical choices for my room and budget but building speakers that I want to have and want to have the experience building. I do care if something is going to cause a problem like having too big mids which I will get smaller 8" ones
Say when I stand in the doorway with all the bouncing sound waves I hear a lot of low sub. Is this from the drivers themselves or the port?
Also I am mainly looking for these to be able to play in my 13ft by 17ft room louder than my ears would want which I would expect with these larger drivers.
I know a lot of these choices for my application are unnecessary but as I stated in this thread the project isn't all about the most logical choices for my room and budget but building speakers that I want to have and want to have the experience building. I do care if something is going to cause a problem like having too big mids which I will get smaller 8" ones
Say when I stand in the doorway with all the bouncing sound waves I hear a lot of low sub. Is this from the drivers themselves or the port?
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The most important bass range in hip-hop is 40-120Hz imo. So I’d aim for 40Hz (or lower) extension.
Some of the PA 12 inch woofers mentioned will make it down that low if you put them in a ported box. You need to model different woofers in a box calculator to see what will work.
The optimal size of the midrange driver will depend largely on the crossover point between midrange and tweeter. For a 12” driver, it should be below about 1500Hz, for an 8” driver you might look at closer to 2000Hz. This depends on the specific midrange and tweeter drivers used though ofc.
The low sub you hear in the doorway likely originated from the port, since the port generally produces the lowest frequencies in a ported system. However, at the frequencies we’re talking about, the room itself ultimately determines the bass response - the speakers are only a minor part of the equation.
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OK.
What I suggested could be playing music within a few days of making the order, which I thought might be important.
Having instant results, and a staged upgrade pathway would, IMO be a good learning curve for a beginner.
The pathway could be:
-modifying the ports on the top box
-then building the bass box
-then adding bracing to the top box
-then improving the crossover
-and so on...
I saw those posts, but I didn't realise you'd locked it in as your plan. It could be a very good plan - that configuration looks like it has potential.
Steep learning curve / delayed gratification, though.
There are bazillions of good articles!
But don't overthink it. Lots of good pro audio speakers are just simple rectangular boxes.
What exactly do you mean?
The best (free or cheap) option depends on what gear you have. What's available to you?
e.g. REW (free software) and a laptop microphone are OK (better than nothing).
For a phone or tablet, the only app I've tried is AudioTool, which is cheap and handy, but not as good as REW.
A proper mic + REW = great.
---
Regarding an earlier question:
Magnet size doesn't directly relate to bass.
Try throwing numbers from spec sheets into this calculator: closed box response plots - it is for sealed boxes, so it is the simplest calculator, and only needs 3 numbers (other than the size of the box). You'll begin to get an idea of how Fs, Qts and VAS relate to each other, and to the box size.
Qts is the parameter that changes (goes down) when magnet strength goes up. Usually cheap drivers have a high Qts.
A moderate to high Qts (around 0.5 or higher) usually works well in a sealed box. The higher the Qts, the bigger the box needed (that's why I was suggesting sealed boxes for the very cheap drivers you were originally looking at).
e.g. the Tymphany FSL-1520R02-08 is a decent looking 15" for only $60, but the Qts of 0.6 means it "wants" about 120 litres.
The $80 Dayton Audio PA380-8 would get similar performance from a 60 litre ported box, (using this calculator).
I'd rather carry a 60 litre box up a staircase than a 120 litre box. That's why most pro speakers are ported
Good morning from the UK!
I'm glad you've decided to go for a smaller midrange. An additional benefit of this is that it will require a smaller midrange enclosure within the main woofer enclosure. (If the midrange enclosure still turns out to be too large then you can go for a 6" midrange.)
I have quoted your post above in the hope that the experts will now focus on helping you design the enclosures for your particular chosen drivers.
But first, please post exactly which 8" midrange you have chosen - we do not have the details of that yet.
If it is the Eminence Alpha-8MRA then it does not even require to be boxed in as it has a sealed back!
This choice, or that of a similar sealed back mid, would be marvellous as it would make the design and construction of the main cabinets so much simpler!
We would simply need to determine which reflex cabinet internal volume would suit a pair of the two 12" woofers, as well as the dimensions of the required reflex vent.
This choice, or that of a similar sealed back mid, would be marvellous as it would make the design and construction of the main cabinets so much simpler!
We would simply need to determine which reflex cabinet internal volume would suit a pair of the two 12" woofers, as well as the dimensions of the required reflex vent.
Thin acoustic foam all around the room is bad idea IMO, as it absorbs only high frequencies (very effectively) and does nothing for other frequencies. The result will be that all the inherent problems of the room will remain, but on top of that, it will sound utterly lifeless.
If you need to put in absorption, I'd start with bass traps. Only if, after that, the room sounds too live in the high frequencies would I put in any thin foam.
FWIW though, your room treatment shouldn't impact too much on the design of your speaker (although this depends on the room, the treatment, and the speaker).
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Also Willhoog, I know you are now planning to buy an off-the-shelf crossover and the 4 Eminence drivers and horn you've mentioned and to design the box yourself.
Can I advise to step back at this point and reconsider using an off-the-shelf crossover that is not specifically designed for the speaker you're building? Honestly, the chance of this crossover working close to correctly with your speaker is almost nonexistent, for a few reasons:
1. Sure, the crossover is designed to work with nominally 8 Ohm drivers. However, driver impedance ratings (Ohm) are nominal, as in reality the impedance is dependent on frequency. A nominal 8 Ohm driver may have different impedances at different frequencies ranging from 5 Ohm to 150 Ohm. The chance of it being 8 Ohm at the crossover frequency is very low. If it is not 8 Ohm at the frequency, the crossover will not function correctly.
2. A textbook crossover (like the one proposed) assumes that all drivers are at the same point in space. Of course, this can never be the case, and distances between drivers - especially differences in the distance from the driver's acoustic centres to the listener - impact massively on the function of the crossover, especially at higher frequencies (i.e. midrange to tweeter). So again, the chances of an off-the-shelf crossover functioning anything like correctly for you are extremely low.
This is why I now repeat my previous advice: learn the art of crossover design in at least some depth, measure the impedance and frequency responses of your drivers in your box, and design your own crossover using modelling software, then refine it by trial and error
OR
Buy parts for a completed DIY design, i.e. one in which the crossover is specifically designed for the speaker being built (e.g. the Tarkus).
The approach you currently seem to be leaning towards is the worst of all worlds IMO
Cheers,
Andreas
Can I advise to step back at this point and reconsider using an off-the-shelf crossover that is not specifically designed for the speaker you're building? Honestly, the chance of this crossover working close to correctly with your speaker is almost nonexistent, for a few reasons:
1. Sure, the crossover is designed to work with nominally 8 Ohm drivers. However, driver impedance ratings (Ohm) are nominal, as in reality the impedance is dependent on frequency. A nominal 8 Ohm driver may have different impedances at different frequencies ranging from 5 Ohm to 150 Ohm. The chance of it being 8 Ohm at the crossover frequency is very low. If it is not 8 Ohm at the frequency, the crossover will not function correctly.
2. A textbook crossover (like the one proposed) assumes that all drivers are at the same point in space. Of course, this can never be the case, and distances between drivers - especially differences in the distance from the driver's acoustic centres to the listener - impact massively on the function of the crossover, especially at higher frequencies (i.e. midrange to tweeter). So again, the chances of an off-the-shelf crossover functioning anything like correctly for you are extremely low.
This is why I now repeat my previous advice: learn the art of crossover design in at least some depth, measure the impedance and frequency responses of your drivers in your box, and design your own crossover using modelling software, then refine it by trial and error
OR
Buy parts for a completed DIY design, i.e. one in which the crossover is specifically designed for the speaker being built (e.g. the Tarkus).
The approach you currently seem to be leaning towards is the worst of all worlds IMO
Cheers,
Andreas
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I need to go for a little bit right now and I will re-read this entire page but this is the mid I had originally saw and it was the only delta 8 ohm one I saw
Eminence Delta Pro-8A 8" Midrange 8 Ohm
But if that one requires too much extra box calculations I might move to the cheaper one that you suggested. I might skip the acoustic foams and just get an Equalizer for my monitors because for producing; the higher frequency sounds like snares sound too alive and are unrealistic.
Eminence Delta Pro-8A 8" Midrange 8 Ohm
But if that one requires too much extra box calculations I might move to the cheaper one that you suggested. I might skip the acoustic foams and just get an Equalizer for my monitors because for producing; the higher frequency sounds like snares sound too alive and are unrealistic.
From a Fane loudspeakers book, I have extracted the following information relating to a twin 12" bass reflex cabinet tuned to the same resonant frequency (Fs = 58Hz) as the Delta-12Bs.
Cabinet internal volume = 4,400 cubic inches (72 litres)
Material thickness = 0.75 inch = 18mm
Diameter of circular vent = 4.5 inches (114.3mm)
N.B. These figures are not based on the T/S parameters of your particular woofers, but can serve as a useful starting point for imagining what your loudspeaker cabinet might look like.
You could practise your mathematical skills right now by converting the internal volume into external height, width and depth measurements. The dimensions of the front baffle (speaker mounting board) are critical as it must accommodate all four of your drivers.
Cabinet internal volume = 4,400 cubic inches (72 litres)
Material thickness = 0.75 inch = 18mm
Diameter of circular vent = 4.5 inches (114.3mm)
N.B. These figures are not based on the T/S parameters of your particular woofers, but can serve as a useful starting point for imagining what your loudspeaker cabinet might look like.
You could practise your mathematical skills right now by converting the internal volume into external height, width and depth measurements. The dimensions of the front baffle (speaker mounting board) are critical as it must accommodate all four of your drivers.
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