Seems like a lot of speaker for a small room. How small?
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End Game DIY Loudspeakers
- Thread starter MKR
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Seems like a lot of speaker for a small room. How small?
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- Jun 5, 2016
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I can't say for sure - basically the width after bookcases was sufficient for 3-seat sofa with space for a door to open inwards on either side. The designer and audition host, @perrymarshall, participates here.
The speakers did not overwhelm the room sonically, and look good so they didn't have a dominating visual presence either. The ratio of displacement to room volume may have been why they didn't suffer from the lack of "slam" I've heard in other OB speakers, including Linkwitz Orions, though.
It turns out this speaker was discussed before here, too with @Duke (another loudspeaker innovator) offering high praise:
2022 Parts Express [Speaker Design Competition] - Over $300 Category
Pasted from PE thread: Unlimited: 1 Charlie Laub 2 Julian 3 Jack Under 300: 1 PaulK 2 JohnH 3 MichaelH Addendum: Nick also placed 2nd in under $300 with Minions, and was later corrected due to an error. Michael was then 4th, etc... Dayton: 1 Tom Zarbo 2 JohnH 3 KeithE Over 300: 1 Dan...
www.audiosciencereview.com
It takes some courage to transport a finely-crafted speaker carefully tuned for results in its natural habitat and transport it for audition by a bunch of judges without benefit of time to tune the low end to a new space.
It’s nice to see some third party praise for the Bitches Brew dipoles. I was thinking about building a pair for a large living room, because they look nice and seem to have that “slam.” I also own a pair of Orion dipoles and they definitely do not have that “slam.”
I replaced the Orions in its small room with a surround setup with Neumann KH310 as LCR and KH120 as surrounds, + multiple subwoofers. It’s interesting—I like both the dipole sound and closed box sound. A lot of people seem to have a strong preference one way or the other.
I am interested to know more about your set up, because my room is a similar size and I like the idea of having LF woofers like that. I am currently looking in to the particulars of a single bass array, but I have questions about your config regardless.@MKR You ask for the best - here it is.
Tweeter - Bliesma T25B
Midrange - Bliesma M74B
LF - Purify. But I use mostly Scan Speak or SB Acoustics/Satori, Purify is REALLY expensive. For a 2 way they are the way to go, in my concept the benefit is small.
Sub - Whatever fits the need! SB34NRXL75-8 is nice.
Did you ever listened to big ATC or PMC speakers? These 3" domes have some magic with them and produce enorm SPL level. My goal is to achive something similar but with the best material available. This Beryllium tweeter is my goto for high frequencies at the moment - prefere it over ribbon or AMT.
But when you really need huge SPL levels you need to step up from the classic 1" tweeter - e.g. T34B.
The whole thing would be driven by a DSP based plate amplifier - I often use Hypex. With the digital input you save a lot of converting, sounds excellent.
Here is a detail picture of my actual setup. T25B, 2x 2,5" Satori Midrange with modified front plate, 2x ScanSpeak 20cm drivers. The midranges get updated to 1x M74B as soon as I have time. LF drivers are positioned close to the position needed for a single bass array - works well <80Hz. No sub needed in my small room but I will go to 10 or 12" in my next build just to get more headroom.
View attachment 281827
The room is for mixing and mastering and listening in near filed. It looks simpel but evey little piece of surface and absorption is optimised, even the table and slanted outboard are matched to the distance to the speakers etc.
View attachment 281829
What you get is sound as detailed as my K812 headphones. I never heard other speakers to be able to do that. But it's way more fun as headphones ;-)
For causual listening this room is way to dampened and you would need a different setup - but that's one way to go "End Game".
p.s.: You will never achieve the precision and details with a compression driver + horn what you get from these beryllium membranes. But you get directivity and insane dynamics - depending on the room and your listening this can be more important.
For me "End Game" means to hear EVERYTHING the source can offer - the system above can do so.
Firstly, is the dimension between the woofers critical, or is that spacing just as close as possible to suit the drivers+boxes? Are the woofer boxes sealed or ported? What is the dark brown at the bottom of the right speaker stack (maybe packers to set the hieght)? Does the top of the top speaker reach the ceiling?
Next I wonder about the actual layout. The front of the speakers looks toed in (judging by the floor lines), so like the green box below? Or is the angle part of the box, like the purple example? And is the angled wall the same angle as the angled speakers? Is there absorption material behind the angled walls?
Lastly, the monitor looks flush between the speakers, and the timber panel above it looks flush too. Is this flush to the ceiling? And is material behind it?
I did see other posts from you that showed how dead your room is, and that it doesn't suit everyone.
These walls left and right of the speakers weren't planed first - they where needed to get rid of a side wall reflection I could not dampen with absorption. Can be removed, e.g. for testing and comparing speakers like KH120ii now. Normally you should build a pretty solid front wall but for my use these wood boards do the job.
The speakers are angled towards the listening position cause I sit pretty close. It would not be a big issue with the T25A but I wanted to use the T25B.
Btw only one of the 2,5" mid domes is active for listening, I needed both cause this speaker was also a prototype/concept for a measurement speaker.
The LF drivers are as close to the mid drivers as possible - which is not the perfect position for the bass array! It still works with a little lower useable range. Sealed volumes cause I like the sound more, want to fill the volumes to have no resonances, want no port resonance and want to EQ down to 20/25Hz. The 4 20cm drivers are at their limit for loud listening with 20Hz content.
The speaker stacks are very solidly built with metal sheets internally against resonances - these 3 pieces are needed to carry them. The brown spacer is for getting the tweeter higher - I'm pretty big ;-), ear level is at 1m30 with my office chair. Speaker reach the ceiling.
When you use the "side walls" how the volume of the speaker is formed is not important. As I planed without them - the back of the speaker sits flat to the back wall. And the side wall next to the PC monitor goes straight back. The baffle of the speaker is angled and the outer side wall is too. I wanted to reach a good transition to the back wall, it would be beneficial to make that more flat, but harder to build.
There is some damping material behind - but in the next build step this will be made better with a more solid side wall, some 19" space below and an entrance for sound waves at the top.
Yes - that's one of the key components of the design! Avoid reflecting corners, get everything flush and neat.
You always need to put some material behind cavities to avoid resonances in that volume. Especially if you want to dampen sound transition. But be careful with moisture when these are cold outside walls! (Yes - you need a pretty wide knowledge of stuff for that kind of installations ;-))
A non environment room is not a living room - it's made special for maximum precision at listening. Some people are sensitive to strongly dampened rooms, some for e.g have big problems in anechoic chambers. (ear & equilibrium & sickness in extreme cases). Therefor you have 2 reflective surfaces, the floor and the wall facing to you to still have a "feeling" for a room. But I had visitors who didn't liked the feeling in the room in the first minutes.
You get used to that quickly - I don't recognise it any more, but I'm also used to work in an anechoic chamber. For me it has a very calming character - it's dead silent and no influence from the outside. A floating tank for every day ;-)
Interestingly my mixes/masterings translate in that room better as ever. Even when it's acoustically total different to a normal living room - you hear what your source gives you. And people are used to the colouration of their room, so you need a "neutral" recording - and that's something you can produce/check in such a room perfectly.
The only thing I give my speakers a bass boost cause that's how most people listen in their rooms. Without I tend to overdo the low frequency area.
You ALWAYS can bring reflections back in to a controlled room! A few wooden pannels/beams with spacings, angled whatever (picture on alubond?) or a nice diffusor and you can create a more lively zone. This is often done in bigger control rooms ("reflection free zone" design) but in a small room you need to be very careful to not get too early reflections!
People confuse "dead" rooms with "dull" rooms cause you never eperience a really good and linear dampened room outside of a good studio. My recording room has the ceiling and long wall totally dampened - and has a fresh character with lots of top end, just very short "reverb". Feels great and works great for recording.
In the handfull rooms I designed we always leave the option to put something on the walls to get reflections back - nobody ever used that option.
(I have a wooden beam around my recording room where I could hang wooden/metal panels to have variation during recordings. Never needed but it's also great to hang guitars there ;-))
Hope that was not too off topic and I got most of your points
Btw - when digging deeper 1-2 books about studio acoustics and building are the best investment you can do!
In my living room and home cinema corner I do a less strict concept. (But I already have a great listening room ;-), it's mainly for watching movies)
There I use a "soft soffit" concept for the front wall where speakers sit in 40cm absorption and everything is behind a screen. Speaker and tech get's hidden and you have a huge absorber for the room. Also an acoustic ceiling above the listening area (with height speaker put in for Atmos).
As I'm not free for positioning absorbing panels (windows) I designed speakers with good directivity to at least dampen side reflections to some degree and get a little less room sound at the listening position.
So every concept dependends on your use case and room and preference - that's the reason for acoustic consulting ;-) (and why it saves a lot of money in the long run when done right)
There I use a "soft soffit" concept for the front wall where speakers sit in 40cm absorption and everything is behind a screen. Speaker and tech get's hidden and you have a huge absorber for the room. Also an acoustic ceiling above the listening area (with height speaker put in for Atmos).
As I'm not free for positioning absorbing panels (windows) I designed speakers with good directivity to at least dampen side reflections to some degree and get a little less room sound at the listening position.
So every concept dependends on your use case and room and preference - that's the reason for acoustic consulting ;-) (and why it saves a lot of money in the long run when done right)
Thanks for all that info. Which books would they be?
"Recording Studio Design" from Newell gives some theory and knowledge + blueprints about non environment rooms. And a lot more.
It's probably the fundation of my adaptation for small rooms and the technology of 2023 ;-)
If you are interested about the building part I recommend "Home Recording Studio" from Rod Gervais. I read this after I did some rooms and pretty often thought "Jep - that's exactly what happens on a construction site"
Of course there is way more, esp about listening and physics and psychoacoustics and ... some even spend years at the university for that to just grab the basics ...
It's probably the fundation of my adaptation for small rooms and the technology of 2023 ;-)
If you are interested about the building part I recommend "Home Recording Studio" from Rod Gervais. I read this after I did some rooms and pretty often thought "Jep - that's exactly what happens on a construction site"
Of course there is way more, esp about listening and physics and psychoacoustics and ... some even spend years at the university for that to just grab the basics ...
This is a very nice speaker with an almost perfect radiation pattern. Since you're considering building the speaker, a quick note on that.
Unfortunately, the designer's statement that this speaker provides constant directivity over the entire listening spectrum is not completely correct. The coax woofer whose crossover frequency is about 80Hz causes a resonance (and its harmonics) with the U-frame (some kind of short transmission line). This leads to a collapse of the dipole radiation in the range of the fundamental resonance and in part around the harmonics.
More details can be found in the thread "Open baffle speaker pitfalls" or directly here.
Absolutely fascinating study! What do you think is the best solution to avoid the directivity blowout & ripples due to the 1/4 wave resonandes? Some brainstorms:
1. Stick with the simple flat front baffle and either deal with less powerful bass, or add traditional subwoofers. This may be the best option anyway, and you can keep an elegant slab look like Perry Marshall’s design. Dipole bass doesn’t magically solve room mode issues, so a multi-sub optimized subwoofer array (with MSO, DLBC, etc) could be the way to go to fix issues under Schroeder anyway. In Perry’s design with a 15” coaxial, he crosses over to the woofers at ~100hz iirc, so one could just implement the top section + rear horn and instead cross over to the conventional subwoofer array.
2. Use an H or W baffle for the bass and cross the woofer(s) over low enough to avoid the resonance issue. The top section of the dipole would be a simple flat baffle. This is basically similar to the Orion design. I ended up needing to add subwoofers to these.
Finally, I wonder if horn loading every driver would address the resonance issue. The horns would add a bit of extra distance from the front and rear of the baffle, while keeping the front narrower, much like folding the baffle into a U shape. For example, let’s say we have something like Scott Hanson’s 3 way design:
But put all the drivers in horns like these limmer horns:
But with the back open. So we have a folded front baffle but break up the vertical height with the top and bottom of each horn mouth. The direct sound from the front would be louder than the rear, which might be desirable. Or they could all be in a single multiple entry horn, but a dipole MEH might be a dumb idea
Everything you say makes sense to me (notice how I'm sucking up and you are not my wife
). Any measure that helps to suppress or weaken the TL resonance is beneficial.However, since the fundamental resonance is often in the 80-200Hz range, depending on the cabinet dimensions, there are limits to the improvement efforts due to the long wavelengths and omnidirectional behavior of the individual drivers (in this frequency range).
Regarding Perry Marshall's design, I would also go in the direction of your first point. Keep the baffle, only one 15'' or 18'' sealed subwoofer at the bottom instead of two OB drivers.
At the crossover frequency to the coaxial driver one can try different things (second order or fourth order crossover,...) to make the transition from omnidirectional to bidirectional radiation as smooth as possible.
The second point would make sense to me if one could do without additional subwoofers. Otherwise, the effort would be too excessive for me personally (huge speaker baffle with huge H-frame plus huge subwoofers - seems like overkill for rooms under 35m²).
I guess this directly applies to the thread, but how much kill is overkill anyways? I always seem to prefer a loudspeaker that is larger than the situation requires turned down to appropriate levels, and I’m not sure I fully understand that. My first theory is dynamic range and compression stop being issues once the displacement requirements disappear. Second is just that I enjoy lots of massive bass boost or bass drivers from playing/dj’ing next to them a lot and having that influence my preferences.
I concur. I would go a bit further and completely separate subwoofers into separate sealed boxes. Then you can optimize placement to avoid SBIR and get a head start on optimizing room modes. For example, dipoles are typically placed away from the front wall. The subwoofers can be placed at the wall or corner(s) to both get additional gain and also prevent the 1/4 WL cancellation in the sub bass region.
And for an DIY “endgame” system, I really think it should include a solution for even bass. The DIY solution is an MSO optimized bass array (Or a DBA or SBA). A 15” coaxial dipole top would get you controlled directivity down to Schroeder and the bass array would supply even, powerful bass in a wide sweet spot.
Off the top of my head, I think and “endgame” DIY speaker system would have:
- Smooth, controlled directivity down to the Schroeder frequency
- Smooth frequency response, on & off axis (due to above). This implies an optimized bass solution, such as an optimized sub array, DBA, etc
- Powerful dynamics
…that’s probably the bulk of it. A burly dipole or very large multiple entry horn could get you there, or a powerful cardioid design. Plus the optimized subs.
AND
- no resonances in the audible range!
- all resonances outside the range of the drivers dampened 30-40dB.
- piston movement of the drivers, keep away from suspension resonance area (the least important?)
Don't get lazy with the requirements!
A 15" with 3" compression driver can give great dynamics - but already has resonances in the audible range.
Can’t precisely tuned FIR filters reverse a driver’s resonance from the source by sending counter-resonant pulses? This seems like how most active designs from new age companies like Sonos and even Klipsch’s new series accomplish perfect FR
Depends on the cause of the resonance. And then, if the particular resonance stays linear with increased drive level.
For example, an internal standing wave has a better chance of correction, than say cabinet vibrations which often don't show up until a certain SPL level is hit.
Great additions! That was just a quick off the top of my head list. In my defense, resonances would be covered by the smooth frequency response requirement.AND
- no resonances in the audible range!
- all resonances outside the range of the drivers dampened 30-40dB.
- piston movement of the drivers, keep away from suspension resonance area (the least important?)
Don't get lazy with the requirements!
A 15" with 3" compression driver can give great dynamics - but already has resonances in the audible range.
Do you think it’s always the case that a 15” woofer crossing over to a CD will have resonances? It’s probably the base case, but can it be done properly?
For example, even the venerable JBL M2 has resonances. Erin believes they are from the cabinet and woofer cone edge/surround:
But this is apparently “fixed” in the JBL 4367 woofer.
I would personally feel better about a ~6” midrange with a flat surround crossed over to the CD and a large woofer for the bass, but then you lose the point source polars unless you fold things like in a MEH.
Speaking of, I believe @gnarly had built several excellent dynamic DIY speakers (properly EQd in the frequency and time domain). If I understand correctly, he ranks them as:
Large multi-way multiple entry horn > 3 way PM90/pm60 (which has better polars) > 15” coaxial in a reflex box.
I’m sure there are multiple reasons, but good directivity control down to, or nearly to Schroeder probability explains a lot of these subjective observations (assuming all are very dynamic, properly speaker eq’d to ~+- 1db, etc).
Hi, i"m impressed you can remember/recount some of my projects !
Yes, I do rank the synergy/unity/meh horns the best.
The PM 90/60's are awesome in their own right, especially given their live-sound intended purpose. I think their nicer polars (at least from CD range up), come from commercial horns with better mouth terminations ( than the terminations I can get from simple DIY wooden conical horns for the synergies).
I would not put the 15" coax reflex build in the same league as the previous two. Nice box, I have it running outdoors flanked by a couple of single 18" subs. But make no mistake, not that close to the others. Even OB, or sealed....
I could go on as to what I think makes for better speakers, but I think my ideas are a little too fundamental and all end up being large, to be of much interest..
Not to mention some of my thoughts/ideas might create a bit of controversy.
Very interesting. One reason I was considering dipole for the living room was for looks, and because they’d be in front of windows with a view. Perhaps I should suck it up and put as large a MEH there is I can stand
. I will be building 1 or 2 pairs of MEHs anyway for other rooms.So the coaxial dipole would have pattern control down to ~100hz. Clearly other variables must trump the nearly full range pattern control and point source polars!
Do you try the dipole coax with subwoofers? This would 1) reduce any modulation or IMD issues by relieving the 15” midrange from moving so much and 2) (the obvious) make the bass region much more dynamic, and allow for optimal placement.
I for one would love to hear your thoughts on what makes for better speakers. Especially the controversial or less conventional takes! Your experience building many different types is invaluable.I could go on as to what I think makes for better speakers, but I think my ideas are a little too fundamental and all end up being large, to be of much interest..
Not to mention some of my thoughts/ideas might create a bit of controversy.
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