I've got my own theory for why some prefer ports and some don't, which simply relates room modal peaks which can easily ruin impression of speaker system. The modal peaks intensity could depend on speaker positioning, but of course the room itself, which is somewhat different for everyone of us. I've come to this conclusion after building big speakers, I'm on fourth prototype bass boxes currently and these are closed and half the volume of first "box calculator" ported boxes, and only now I do not have to cut room modal peaks with EQ. Bass was simply overwhelming with bigger boxes, while I could just EQ them I could just go smaller and closed to avoid some other issues like port noise, reduced cost and surface area overall, and aesthetics. I had feature of too much bass capability which came with trade-offs and I could just make those go away sacrificing the excess. These still have box volume and volume displacement of several average bookshelf speakers which enables plenty bass without unnecessary trade-offs and gets towards problem free speaker, at least more problem free than it was before.
So, I think there is no universal truth which is better. Given same room and person either closed or ported could work. Even then perhaps small speakers could benefit from ports to have some impact, even if it was from modal peaks, and so on, try out and choose the better more suitable one. One could experiement by blocking a port, or build another better suited set if there is luxury to make prototypes until "optimal to situation". If there is one conclusion from all this is I think EQ really helps, perhaps in all situations. I'll never depart my DSP.
So, I think there is no universal truth which is better. Given same room and person either closed or ported could work. Even then perhaps small speakers could benefit from ports to have some impact, even if it was from modal peaks, and so on, try out and choose the better more suitable one. One could experiement by blocking a port, or build another better suited set if there is luxury to make prototypes until "optimal to situation". If there is one conclusion from all this is I think EQ really helps, perhaps in all situations. I'll never depart my DSP.
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My one-penny-thought: make sure 5khz is not deficient else music won't sound dynamic. My favorite 5" fullrange in a 10L 1.3m tapered transmission line played Karajan's Dvorak bass drum concerto nee 9th so exhilaratingly I could not stay seated. The "drum paper" speakers had a very narrow 5khz sharp peak -- once notched, I could listen to music forever and enjoy every note and nuance -- seated. To me the challenge of classical music is "polyphony" where each musical part "sings" melodiously and with verve, and they all sing together in conversation. This is true for all music not only classical, but even chamber pieces with piano are extremely complex, and difficult for audio.
They Carreras are nice and sound great; They sound even better when crossed to a woofer/sub at 100-150hz.
@Alpigiano : what’s about your room? If you can place speaker outside from front wall then a competent dipole speaker like NaO Note II RS can be better for classical music than any three way box speaker, and they do not require much wood working
I did some homework after your feedback, and modelled a few options for woofers. I have also re-drawn the boxes to be deeper and allow for more volume, up to 55-60 lt. I still prefer the original design but I could live with it.
I attach a table with all the numbers, but this is probably information overload, so I'll try to summarise.
What I did:
Conclusions:
Details and questions:
Thanks a lot again!
I attach a table with all the numbers, but this is probably information overload, so I'll try to summarise.
What I did:
- I modelled a few drivers in my shortlist as either single or 2x, depending on their Vd and Re
- Calculated Closed, BR and also the max LW transform the driver could sustain before running out of linear excursion. The latter is mostly for reference in case I found myself with too much SPL and wanted to extend the range. I used VituixCAD
- Also added expected SPL based on Vd and Small's formulas (i.e. not sensitivity and watts). Cross-checked here.
- Limited the box size to a Vb of 58.3 (that's what approx came out of my drawing)
- Added a pro driver from Eminence that Tekton uses, mostly for reference
Conclusions:
- I don't think a 2x setup will work. Either too much Vb required, too much baffle space or too little Sd. And more expensive
- If I want a lot of SPL, I'll be better off with a sub or two.
- Front runners are SS Discovery 26W/4534G00 (used by Troels in his Discovery 3WC-10, which TBH that's a pretty good design for my use case, I can make the box a little shorter & deeper), Satori WO24 (P or TX), and another SS, Revelator 26W/4867T00, also a Troels pick as it was pointed out by @duvixan
Details and questions:
- I wasn't impressed by the WO24P midrange when I heard it. It didn't sound as musical as a Wavecor to me. But it models well, it's good value and I could cross it low. I've read that the TX version is cleaner, but it's more than twice the price. Worth it?
- 2x 8'' Wavecor WF223BD01 (4 Ohm) in series actually models the best of all 2x here. But it's difficult to justify the cost over the SS 26W/4534G00, unless the higher Qms and lower Rms actually make enough of a difference at low volume. Or if I want to cross it higher (to a dome midrange). Am I missing anything?
- The SS Revelator models really well, it's expensive but still cheaper than 2x configurations. I only wish Qms and Rms were comparatively better. This is where my lack of experience suggests to save my cash. Is this the right approach or am I putting to much weight into T/S parameters?
- The SS Discovery looks like really good value. Even half decent in a closed design, so I could experiment with the safety of using Troels' design if closed doesn't work. It can take a lot more in BR, feels like I'm wasting it a bit.
- The Eminence is a very interesting piece of kit. I will try to listen to it. I'm a bit nervous about using a guitar driver, I worry that it won't be as good on transients. Should I be though?
Thanks a lot again!
I wonder if this is why I liked the Morel dome 'filler' midrange? But yes, I will be careful in the 2-5k range.
While I was modelling all the drivers, I was thinking the same. I need to try them with a high pass. I will do some tests as soon as I get some time. I only have a crappy sub on hand but it may be enough.
I've just realised that in my calculation and tables I haven't adjusted Rms and Mms for the 2x options. If anything, that makes the 2x options even harder to justify. Sorry about that!
Hi all - I've been swamped at work and with other projects and haven't found the time to update on my progress. I am sure you coped just fine, but here is where I am at.
Also, I've done some baffle modelling to learn about how driver placement affects directivity. One of my constraints is that vertical directivity needs to be good, even at the expense of horizontal past say 45 degrees. The speakers are going to be placed lower than ideal (about 15 deg) for aesthetic reasons.
I haven't decided on mid and tweeter yet, but with my choice of woofer, the Morel EM-1308 is out unless this becomes a 4-way. I attach some pics:
This is going to be a slow burner I'm afraid but I am happy to keep updating it. Any thoughts welcome - I am sure I've overlooked many things.
- I'm going to start by ordering a calibrated microphone and a SS 26W/4534G00 and do some prototype modelling in a box. I am still aiming for a closed box and I reckon it should work (99db @40hz). If it doesn't, I will have to sell it as I can't make a box big enough to use it in BR I don't think. But I'm happy with the risk and keen to get some sawdust and real world data.
- I want to then experiment by hi-passing to the Carreras, using the 4534G00 for low frequencies. I did manage to do that with a subwoofer and A/B tested it, but I didn't see a huge improvement in instrument separation for orchestral music. There could be many reasons that I tried to control for but I was not convinced. It still feels that the transients are not as agile as I would like.
Also, I've done some baffle modelling to learn about how driver placement affects directivity. One of my constraints is that vertical directivity needs to be good, even at the expense of horizontal past say 45 degrees. The speakers are going to be placed lower than ideal (about 15 deg) for aesthetic reasons.
I haven't decided on mid and tweeter yet, but with my choice of woofer, the Morel EM-1308 is out unless this becomes a 4-way. I attach some pics:
- 3 way: using ideal drivers, haven't traced or measured anything. Using LR4 for now, until I start to measure. It's very interesting to see how moving the drivers around affects directivity. I'm only showing horizontal up to 45 deg but vertical is very similar in this config.
- 4 way: I've discovered the niche 'tweemid' TM 4055 from Morel that I modelled (labelled as 4-way in the pictures). This may be the only way for me to still use a midrange dome, so I was curious to model that. It's attractive because I could just turn it around and effectively control most of the directivity on the same baffle (there is another crossover at ~800Hz but I think that's less critical).
- Using a coaxial - of course best for directivity (not modelled here yet, with ideal drivers it will look perfect). Does anyone have any experience with the SBA Satori MT19CP-8? T/S parameters look good, but very little info online.
This is going to be a slow burner I'm afraid but I am happy to keep updating it. Any thoughts welcome - I am sure I've overlooked many things.
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hi, if vertical must be good you could lay the speaker on it's side 😉 or use coax. In general, less ways makes less vertical polar issues. I'd do three way, coax + woofer
The 20log function of course applies to Voltage or sound pressure. For power calculations use 10log. So you end up at 85dB with 1/16W.
Couldn’t resist that, re-reading the topic.
@op did you consider a 2-way? A coaxial driver 3-wat causes a lot more headache than a 10”-1” with appropriate waveguide. And since the coaxial unit works as a waveguide already, the 2-way alternative seems viable to me, the SS 26W does 1,2kHz easily.
Basically, that's what I am doing by inclining the tweeter vs mid to reach a good compromise. But I might model a horizontal setup to see if I get better results. Maybe I wasn't clear, but I would like to have good horizontal directivity up until 30-45 deg not to go crazy with positioning and toe-in. For vertical, I could incline the baffle back by say 15 deg and adjust the delays if needed. Bit more of a carpentry pain so I'd like to avoid it!
@markbakk Thanks for your suggestion - I considered it briefly. Especially the SS Revelator 10'' can be crossed quite high according to reviews (I cannot find the one I am thinking of, a French guy compared a few 10''). But my feeling (and it's just a feeling) is that separating deep percussions from the midrange fundamentals of most instruments will have better results. And will not be that much more expensive.
Why do you say coaxials can be a headache? My reservation with coaxials is that the engineering of the driver itself becomes so critical to voicing the speaker that I don't know if I would be able to make it work. There are a few designers who can do it well and we all know who they are - and I'm pretty sure they didn't use off the shelf components. But I'd like to hear your thoughts! Thank you
Why do you say coaxials can be a headache? My reservation with coaxials is that the engineering of the driver itself becomes so critical to voicing the speaker that I don't know if I would be able to make it work. There are a few designers who can do it well and we all know who they are - and I'm pretty sure they didn't use off the shelf components. But I'd like to hear your thoughts! Thank you
I use your post as an example why one should ideally start a speaker design from the requirements, which stem from your context and use case, what you want to perceive, and forget about all technical details until you have an idea what you want and why. It might take quite some while to think this stuff through and experiment and do calculations, so often it is necessary to just go ahead and make some speakers and then better them up if feel like it later in life. Anyway, deciding number of ways and buy drivers first and then feel pain to make a system with them to meet expectations is backwards. It's like making triangle shaped peg, because one feels like so, and then trying to fit it into a square hole.
To meet perceptual expectations one should design system first to the requirements from perception perspective, not from technological perspective, and only at the end of a design process you'll know which drivers to buy. One shouldn't even think any brands and models until one is sure the design fits what one expects from the system. For example here, if the speaker needs to sit low, then start figuring out how to achieve expectations with that limitation. First thing would be to be sure the expectations are known and realistic and then study what needs to happen to meet them.
Example: furnishing could be quite effective acoustic treatment for low sitting speakers, so room sound is affected quite much compared to ear height speakers. Also listening distance affects how early reflections play with perception. So, if you want to utilize your room early reflections to "enhance" the stereo sound then speakers below furnishing level kind of takes away from it assuming you have furnishing, and could also make the vertical lobes more audible so your concern is right in that sense but the vertical lobes aren't the only problem now if you don't have the early reflections you expect. Conversely, if you have the early reflection "enhanced" sound the vertical lobes likely don't hear through because what you hear by definition is mostly the room, not the direct sound. Listening distance matters in two ways, good main lobe is bigger further away, and so are the early reflections dominating more so the lobes are issue mostly on short listening distance, while further away DI is more important. How far is close and far in your place and speakers and positioning? This is something you could experiment with what ever speaker you have now.
So, depending on what you expect and what your room is like, vertical lobes might not be any issue at all. Perhaps you might be better of with some open baffle system to have great DI and enough room sound? Or, Is tilting back the speaker an option? All this stuff is context dependent, only figured out by you, the end user, the designer.
To meet perceptual expectations one should design system first to the requirements from perception perspective, not from technological perspective, and only at the end of a design process you'll know which drivers to buy. One shouldn't even think any brands and models until one is sure the design fits what one expects from the system. For example here, if the speaker needs to sit low, then start figuring out how to achieve expectations with that limitation. First thing would be to be sure the expectations are known and realistic and then study what needs to happen to meet them.
Example: furnishing could be quite effective acoustic treatment for low sitting speakers, so room sound is affected quite much compared to ear height speakers. Also listening distance affects how early reflections play with perception. So, if you want to utilize your room early reflections to "enhance" the stereo sound then speakers below furnishing level kind of takes away from it assuming you have furnishing, and could also make the vertical lobes more audible so your concern is right in that sense but the vertical lobes aren't the only problem now if you don't have the early reflections you expect. Conversely, if you have the early reflection "enhanced" sound the vertical lobes likely don't hear through because what you hear by definition is mostly the room, not the direct sound. Listening distance matters in two ways, good main lobe is bigger further away, and so are the early reflections dominating more so the lobes are issue mostly on short listening distance, while further away DI is more important. How far is close and far in your place and speakers and positioning? This is something you could experiment with what ever speaker you have now.
So, depending on what you expect and what your room is like, vertical lobes might not be any issue at all. Perhaps you might be better of with some open baffle system to have great DI and enough room sound? Or, Is tilting back the speaker an option? All this stuff is context dependent, only figured out by you, the end user, the designer.
Mainly because you have to figure out a crossover somewhere around 300-500Hz. That requires a lot more (mainly space) for reliable measurements. Adequate measurements around 1kHz are easier to accomplish.
@tmuikku What you say makes perfect sense. I am just discovering things as I get along. I think that for less experienced people, it is natural to listen to speakers and assume that the drivers are the most important part of the system. From my point of view, I want to analyse all the components so I learn their relative importance and how much effort to spend on each when it comes to building it. Or ideally so that I learn to identify the cause of problems and think of solutions...even if the order is not the most intelligent one, I guess that's experience.
I did in fact also model the room (and the baffle shape) a while back, and that has a big impact; but I also think that room simulation has the biggest margin for error. So I won't panic until I have real measurements. If I add the room to VituixCad, it dwarfs the fine tuning of crossover and driver position and I'd rather isolate each challenge.
Vertical lobes are OK. Still there, even with 3m high ceilings 🤷♂️ but the most problematic issue with deep cabinets will be mid-bass suckout. I plan to experiment with acoustic panels and see where I land.
I did in fact also model the room (and the baffle shape) a while back, and that has a big impact; but I also think that room simulation has the biggest margin for error. So I won't panic until I have real measurements. If I add the room to VituixCad, it dwarfs the fine tuning of crossover and driver position and I'd rather isolate each challenge.
Vertical lobes are OK. Still there, even with 3m high ceilings 🤷♂️ but the most problematic issue with deep cabinets will be mid-bass suckout. I plan to experiment with acoustic panels and see where I land.
Hi, yes there are million things 🙂 Point with drivers is that you can always choose the best ones, what ever that is to you, but before the system is designed you just don't know what the best ones are. For example, very very good drivers from Purifi or any other top shelf brand are tempting for best sound, but if you buy say 6" model or 8" model, but later find out best concept doesn't have those size drivers but a 12" and 3" for example, then it was for nothing, right. Design first, then buy suitable ones, now you know what they are. If the fashionable "best" ones are not suitable, don't agonize over, you have your own system designed for you and now you know what you need for it to work as designed, doesn't necessarily have to be top of the pops.
I'm not sure how deep cabinets result in midbass suck out, I think it's more how the system works with the room (positioning) and any depth box with same positioning would have pretty much similar issues. One could use gradient system, like dipole or cardioid, to reduce sound toward first reflections on some boundaries, but if you check in simulator (VCAD room tab for simplest) floor and ceiling reflection can alone make huge suck out, which height of things matter as well. Yeah it is a real issue to worry about, it's just multidimensional and if you start optimize for mid bass suck out prepare to juggle the concept quite a bit, and it might be impossible with low standing speaker. In general, most loudspeaker problems land on midrange so it's worth trying to address as many as possible in order to get better sound, especially the worst ones, what ever those are.
Any speakers get you some sound, and if it's fine to you then it's all good. The more you dig into it, spend time listening and studying, the more you'll discover things that might help with sound you want. But, one could be happy with what ever. What ever seems most fun, some like to tinker, some don't. So, my main advice is: have fun!🙂
I'm not sure how deep cabinets result in midbass suck out, I think it's more how the system works with the room (positioning) and any depth box with same positioning would have pretty much similar issues. One could use gradient system, like dipole or cardioid, to reduce sound toward first reflections on some boundaries, but if you check in simulator (VCAD room tab for simplest) floor and ceiling reflection can alone make huge suck out, which height of things matter as well. Yeah it is a real issue to worry about, it's just multidimensional and if you start optimize for mid bass suck out prepare to juggle the concept quite a bit, and it might be impossible with low standing speaker. In general, most loudspeaker problems land on midrange so it's worth trying to address as many as possible in order to get better sound, especially the worst ones, what ever those are.
Any speakers get you some sound, and if it's fine to you then it's all good. The more you dig into it, spend time listening and studying, the more you'll discover things that might help with sound you want. But, one could be happy with what ever. What ever seems most fun, some like to tinker, some don't. So, my main advice is: have fun!🙂
Completely agree with this suggestion! https://www.diyaudio.com/community/threads/open-source-monkey-box.327594/
Can't think of any other as well documented designs that may get closest to the ATC mids you said you liked the most out of what you've heard. And no faffing around with sh**y miniDSP / class D amps!