I just ran across a design type I wouldn't mind seeing as a detailed build guide. An Ikea-bowl waveguide MTM. (spotted over on the "DIY Loudspeaker Project Pad" fb group).
An externally hosted image should be here but it was not working when we last tested it.
I don't really know the particulars, a guy just posted his build there. Looks like Ikea large bowls used as both woofer cabs and walls for the waveguide. Looks like something a new diyer could get together with a minimum of woodworking tools (maybe 3D print the waveguide walls, or use a jigsaw?), and get a pretty advanced design type.
No plots supplied in the fb posts, nor crossover details. But those could be worked out by the generous help of people here if it suited them to do that.
No plots supplied in the fb posts, nor crossover details. But those could be worked out by the generous help of people here if it suited them to do that.
That's a beautiful looking project.
A few different Ikea parts are involved.
Thanks! Bill for mentioning it here.
I see that it sits on what looks like a sub-woofer.
The above pic ( upon a close look ) illustrates nicely that the ikea cutting boards are inserted ( slotted ) into the sides of the round bowls.
- This will also help break up some pretty severe standing-wave modes.
PS; And to think I was recently thinking of tossing one of those same Ikea chairs.
A few different Ikea parts are involved.
Thanks! Bill for mentioning it here.
I see that it sits on what looks like a sub-woofer.
An externally hosted image should be here but it was not working when we last tested it.
The above pic ( upon a close look ) illustrates nicely that the ikea cutting boards are inserted ( slotted ) into the sides of the round bowls.
- This will also help break up some pretty severe standing-wave modes.
PS; And to think I was recently thinking of tossing one of those same Ikea chairs.
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What I would like to see is an allround simple very cost effective cross reference speaker.
Available anywhere in the world.
One that we can all cross reference to for reasons to obtain accurate measurements when designing and checking our diy builds and where advice can be given on complex builds once the reference measurements have been satisfied a bit like a universal reference that in its own right would put normal tv speakers to shame so a pair would be a significant upgrade
That would eliminate dodgy microphones and pc based measuring equipment and newbies thinking that a 50db measurement scale flat is great
Something simple like a £5 or£10 driver and boxed accordingly with minimal components and complexity
Available anywhere in the world.
One that we can all cross reference to for reasons to obtain accurate measurements when designing and checking our diy builds and where advice can be given on complex builds once the reference measurements have been satisfied a bit like a universal reference that in its own right would put normal tv speakers to shame so a pair would be a significant upgrade
That would eliminate dodgy microphones and pc based measuring equipment and newbies thinking that a 50db measurement scale flat is great
Something simple like a £5 or£10 driver and boxed accordingly with minimal components and complexity
Here is the text from his original post:
"Almost done...
2x Ikea APTITLIG 45x28
4x Ikea APTITLIG 24x15
8x Ikea BLANDA MATT 28cm Φ
4x Ikea BLANDA MATT 12cm Φ
1x Ikea NOLMYRA"
So, yeah, Blanda bowls plus other stuff
A pic of the HF driver mounting from the back
An externally hosted image should be here but it was not working when we last tested it.
Even more clever than I thought - he sawed slices out of the bowls to put flat boards in for the side walls, rather than trying to get the side walls to lie flat across the bowls. I don't see what he used the 12cm Blanda bowls for, though.
--
Edit: Ah, I see it now. The smaller bowls are used to widen the mounting surfaces for the midwoofers.
EarlK, yeah, I think subs would be needed -- those bowls are only 11" diameter.
(OK, I'll stop hijacking the thread about this. I asked the guy on fb if he'd consider doing a build thread here.)
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This is heading in the right direction.
The things available at the diyAudio store are fairly unique, and hard to get elsewhere.
I speculate that the ACA could well become Nelson’s most popular amplifier. Don’t let the low power rating fool you, this amplifier has very well behaved performance when clipping so sounds much bigger.
I had been using an ACA with 85 dB speakers (Jordan Eikona2) and even in my big room was happy. Now running a pair as monoBloks and the extra power (and lower damping) is appreciated.
A FR speaker can provide the benign speaker impedance, can be fairly easy to put together (no XO!!) and can have modest cost even with some very good FR drivers.
dave
But how do you know what your measuring is real
What can you cross reference them with to know your measurements are right or in the ballpark
Your pc could be faulty your amplifier could be duff or wiring could be wrong
This would eliminate the unforeseen
Can anyone say in general what might be the expected performance of the horn formed by two straight side walls and two spheres? Perhaps the designer has done some extensive measurements on and off axis that could show this?
I like the poll idea suggested by the OP. It might be useful to start a new poll thread?
Another idea that came to me as I was mulling this over is some kind of yearly loudspeaker design competition. The winning design becomes that year's DIYaudio loudspeaker project. There could be one or two design contests per year. The theme could be changed up each time to suit the many different types of loudspeakers and crossovers (passive vs active vs IIR only DSP vs full out IIR+FIR DSP). Full details of the design and some background info and designer input RE motivation, design goals, etc. could be included. This way people might learn the craft from each winning loudspeaker design instead of just using it as a way to generate some loudspeakers that people can build. A design contest can be done by specifying design criteria that the designer must meet (type of loudspeaker, budget, size of loudspeaker, number of drivers used, etc.) or by stating that a certain set of drivers must be used in the project. For example, the project must use mid-woofer model X and tweeter model Y, then designers are free to choose an MT, MTM, MMMT mini tower, etc. There are many creative ways this can be done. The designer should lay bare all the project info from start to finish so that people can learn something from the project, or at least I think that is worth shooting for here at DIYaudio.
Looking cool/interesting is a plus, however, I think that any "endorsed" loudspeaker design should be vetted through measurements. Just like when someone posts about a new amp - everyone wants to see the detailed schematic. For loudspeakers this means (to me) a set of on and off axis measurements of the final project plus the crossover design. Of course all this info makes the project easy to copy, but that is out of our control and is actually more or less what we want to provide: open source loudspeaker designs.
Anyway, I hope my input above is construed in a positive way and not the rantings of an old man or whatever.
"The Big Easy" o.k. we now have a name. need at least 10 buyers to succeed
Goal: Once-in-a-lifetime bargain price on "The stuff that dreams are made of."
The BIG EASY ... Use the power of this audio community for a group purchase of hard to get SEOS-24 waveguide with the new BMS 4594HE_ND coaxial compression driver(goal $700) to cover 500-20,000Hz with excellent pattern control. A slot loaded push-pull woofer improves directivity with efficiency approaching ~100db. One 18" woofer, or two in WTW configuration, also offer high efficiency with a large... but easy to build big cabinet.
Goal: Once-in-a-lifetime bargain price on "The stuff that dreams are made of."
The BIG EASY ... Use the power of this audio community for a group purchase of hard to get SEOS-24 waveguide with the new BMS 4594HE_ND coaxial compression driver(goal $700) to cover 500-20,000Hz with excellent pattern control. A slot loaded push-pull woofer improves directivity with efficiency approaching ~100db. One 18" woofer, or two in WTW configuration, also offer high efficiency with a large... but easy to build big cabinet.
Attachments
Hey, if people will buy a 6.5" full ranger for more than $1000/pr on this forum, I do not think that is an unreasonable expectation at all!
I'm not sure I would go with MTM. You have to be able to move the dang thing, ya know? And two 18s plus a big horm in a large cabinet would be very, um, weighty. One way that could accommodate both would be to make the design modular:
>> SEOS chamber to hold horn and crossover or electronics
>> 18 woofer chamber
Then people could build it up as an MT with woofer chamber and SEOS on top, or do an MTM by adding another "woofer chamber" stacked on top of the SEOS chamber.
Also, your push-pull slot loaded concept is not good since you need those driver to operate up to >500Hz. The slot creates a resonance which causes significant dips and peaks in the response, and these will occur below 500Hz if you use 18s in the slot (e.g. the slot is circa 20" deep).
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Very good point Charlie2. having the tool is one thing, actually being able to use it properly is a very different thing. Having a reference to check your results against makes a lot of sense!
I've been taking measurements for a long time now and it still surprises me every now and then when some variability creeps in. See Attached. This is the exact same speaker measured in the same place in my backyard. Black curve on 30th June, Blue curve yesterday.
There were probably three differences between these measurements. The one on 30th June I had the saw horses that were holding my speaker turntable oriented differently and had a large F clamp protuding out to the side.
The second difference is the 30th june measurement was done with Mic on tripod which is not tall enough with the mic wand angled up at about 45deg (it's an omni mic so theoretcially shouldn't make a difference, but reality says otherwise.
Third difference is that yesterdays measurememt had the tripod mounted on a step ladder. So that the mic boom could be straight on.
The 30th June measurements were cleaner and allowed a longer gate time, but I think that yesterdays measurements are probably more accurate. However without a reference how would you know.
There is a hell of a lot more to getting good measurements than having a calibrated microphone. Note that these measurements are with an uncalibrated mic, but I have measurements of this speaker from 5 or more years ago that match very closely to what I measured yesterday. The setup is equally important, and without a reference, how do you know you have set up properly!
1st picture is the setup 30th june (black curve) 2nd pic is setup yesterday (blue curve).
Attachments
There is no need for a "universal reference" speaker. That's not possible anyway, because any one driver out of the thousands that are created at the manufacturing company can all vary from each other somewhat. Even if there is just the driver in a box, this cannot serve as an accurate reference because of the variability in the drivers themselves.
What might be better for you is an "internal" reference, that is some speaker that you put in your measuring location and then measure before measuring the unknown speaker. That would allow you to check the measurements setup to make sure it is the same as the last time by comparing the last measurement of the internal reference speaker to the current one.
Anyway, the proper use of a calibrated mic is BY FAR THE BEST REFERENCE! That's what a calibration corrected microphone is supposed to be for. A mic is after all a small transducer, just like a speaker. Everyone should be "correcting" the measured response by the calibration curve of their mic after each measurement (typically via the measurement software). When a microphone has been "calibrated" this does not mean the mic alone is a reference standard, only that the mic response PLUS THE CORRECTION CURVE are close to the response of a REFERENCE MIC. And any microphone's response can drift over time, meaning after several years that calibration curve may actually be "expired" and the mics' response has changed. You can get it re-calibrated periodically if you really want something accurate.
Anyway, I use caps to emphasize points above. Wintermute and others, you may already understand these concepts well, it is mostly for those who might not.
What might be better for you is an "internal" reference, that is some speaker that you put in your measuring location and then measure before measuring the unknown speaker. That would allow you to check the measurements setup to make sure it is the same as the last time by comparing the last measurement of the internal reference speaker to the current one.
Anyway, the proper use of a calibrated mic is BY FAR THE BEST REFERENCE! That's what a calibration corrected microphone is supposed to be for. A mic is after all a small transducer, just like a speaker. Everyone should be "correcting" the measured response by the calibration curve of their mic after each measurement (typically via the measurement software). When a microphone has been "calibrated" this does not mean the mic alone is a reference standard, only that the mic response PLUS THE CORRECTION CURVE are close to the response of a REFERENCE MIC. And any microphone's response can drift over time, meaning after several years that calibration curve may actually be "expired" and the mics' response has changed. You can get it re-calibrated periodically if you really want something accurate.
Anyway, I use caps to emphasize points above. Wintermute and others, you may already understand these concepts well, it is mostly for those who might not.
In fact I just got back from purchasing an IMM6 which I will use to compare to my WM-60AY based mic (not the be all and end all of calibration, but better than nothing). I know there are likely some wiggles in the higher freq which are due to the mic, but I've never been sure how much.
edit: and yes Charlie no two speakers will ever be the same unless carefully matched, but I guess the point charlie2 was making was that a "reference" could at least give you some confidence that you are in the ball park with your measurements
Tony.
edit: and yes Charlie no two speakers will ever be the same unless carefully matched, but I guess the point charlie2 was making was that a "reference" could at least give you some confidence that you are in the ball park with your measurements
Tony.
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That's an excellent idea as builders can have a hard time navigating and finding what's hot and what's not in the various types of designs. If a good example is given for the various categories, would be helpful for builders.
I might kick off a thread and if moderators don't think it's appropriate then they can delete it. If they like the idea it can become a sticky.
"High end" and "limited" needs defining, they will mean something different to everyone you poll.
Hi everybody,
If I'm not wrong, the DIY Audio 3-way reference project has ended with the choice of Seas CA26RFX, ER18RNX, 27TDFC.
I would like to build a 3 way like this one in an active version or an variant with U18RNX/P and 27TBCD/GB-DXT.
I like the idea of a modular approach with 10"+7"+1" speakers, builder could start with a two way and tadd in a second time a 10" to get a three way.
Filter could be proposed in active and passive or hybrid passive MT / active WM.
Sure theres are lots of good designs here on Diyaudio, but I've not seem much active designs fully described. DSP and amps are not really expensive now, so it may be the way to go.
I think the combo 10"+7"+1" is the type of speaker that you can qualify of Hi-Fi and could suits most living rooms.
Anyway a poll is a good idea.
BR,
Pascal
If I'm not wrong, the DIY Audio 3-way reference project has ended with the choice of Seas CA26RFX, ER18RNX, 27TDFC.
I would like to build a 3 way like this one in an active version or an variant with U18RNX/P and 27TBCD/GB-DXT.
I like the idea of a modular approach with 10"+7"+1" speakers, builder could start with a two way and tadd in a second time a 10" to get a three way.
Filter could be proposed in active and passive or hybrid passive MT / active WM.
Sure theres are lots of good designs here on Diyaudio, but I've not seem much active designs fully described. DSP and amps are not really expensive now, so it may be the way to go.
I think the combo 10"+7"+1" is the type of speaker that you can qualify of Hi-Fi and could suits most living rooms.
Anyway a poll is a good idea.
BR,
Pascal
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I think this project will be difficult to get off the ground, and the rest of the thread is a good indication as to why.
HiFi amps are fairly standard in a lot of ways - I think we can all agree that a 100w/ch@8ohm solid-state amplifier will be useful in a lot of HiFi systems. There's also the low-power stuff like valves and class A solid-state amps - popular enough that people are willing to find high-efficiency speakers to use with them.
Speakers, on the other hand, are much more subjective and personal.
I'm using some 6.5" 2-way speakers and they go more than loud enough for my room. In fact, they're designed as PA speakers. Bass extension is limited, so I add a subwoofer.
Other people might have space for a classic 15"/5"/1" 3-way design, but I certainly don't. It'd use up too much space, and the additional SPL levels that such a system could attain, I'd never use. If a PA-driver-based 6.5" 2-way can get loud enough with low distortion, what's the point in going bigger?
Some people like the OB sound, where half of it goes backwards. I'm not too keen myself - the time-smearing messes up the imaging IME. Plus, I don't have space to keep them 3'+ away from all walls.
Some people like full-range drivers. I like them for some sorts of music, but I haven't found one that can play Bon Jovi at the levels it ought to be played at, apart from the big Fane units which demand very large cabinets, and still don't go particularly deep into the bass.
The multi-entrance horns are a good idea, and I'd love to see something happen with those - perhaps it'd be possible to sell the CNC'd horn walls with the matching midrange drivers and a 1" bolt-on HF horn entrance.
However, a horn with pattern control down to a useful frequency will be very large again, so that takes out a chunk of the market.
So, now what?
There's a lot of tried-and-tested speaker designs out there. It's unlikely we're going to come up with anything revolutionary, so I think, if there is to be a diyAudio speaker, something small-ish, solid, and cheap like a 5" 2-way based on something like the Peerless standard range would be the thing to do. Aim for less than 10 parts in the crossover, and add tweaks as follows:
- BSC adjustment for near-wall/corner placement
- HF tilt for bright rooms
I think the option to go from a stand-mount ported box to a floor-standing ML-TL would be worth having, too.
Another option could be to add a 12" driver and make it a 3-way, but the 2-way section would need to be unchanged apart from the BSC section.
Chris
HiFi amps are fairly standard in a lot of ways - I think we can all agree that a 100w/ch@8ohm solid-state amplifier will be useful in a lot of HiFi systems. There's also the low-power stuff like valves and class A solid-state amps - popular enough that people are willing to find high-efficiency speakers to use with them.
Speakers, on the other hand, are much more subjective and personal.
I'm using some 6.5" 2-way speakers and they go more than loud enough for my room. In fact, they're designed as PA speakers. Bass extension is limited, so I add a subwoofer.
Other people might have space for a classic 15"/5"/1" 3-way design, but I certainly don't. It'd use up too much space, and the additional SPL levels that such a system could attain, I'd never use. If a PA-driver-based 6.5" 2-way can get loud enough with low distortion, what's the point in going bigger?
Some people like the OB sound, where half of it goes backwards. I'm not too keen myself - the time-smearing messes up the imaging IME. Plus, I don't have space to keep them 3'+ away from all walls.
Some people like full-range drivers. I like them for some sorts of music, but I haven't found one that can play Bon Jovi at the levels it ought to be played at, apart from the big Fane units which demand very large cabinets, and still don't go particularly deep into the bass.
The multi-entrance horns are a good idea, and I'd love to see something happen with those - perhaps it'd be possible to sell the CNC'd horn walls with the matching midrange drivers and a 1" bolt-on HF horn entrance.
However, a horn with pattern control down to a useful frequency will be very large again, so that takes out a chunk of the market.
So, now what?
There's a lot of tried-and-tested speaker designs out there. It's unlikely we're going to come up with anything revolutionary, so I think, if there is to be a diyAudio speaker, something small-ish, solid, and cheap like a 5" 2-way based on something like the Peerless standard range would be the thing to do. Aim for less than 10 parts in the crossover, and add tweaks as follows:
- BSC adjustment for near-wall/corner placement
- HF tilt for bright rooms
I think the option to go from a stand-mount ported box to a floor-standing ML-TL would be worth having, too.
Another option could be to add a 12" driver and make it a 3-way, but the 2-way section would need to be unchanged apart from the BSC section.
Chris
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