Hello All,
It's been literally years since I posted here, but I thought I'd share my latest effort.
Disclaimer: still finishing the build - have not listened to them yet.
I call these the "AluMinis" after the driver diaphragm materials and the compact nature of the cabinet dimensions.
The basic goal was a simple yet modern-looking, small footprint, full-range 2-way speaker with high-value drivers. The cabinets are only about 5.5" wide, 32" tall and 10" deep; straight on they take up very little visual space. I used 1/2" mdf - in the future it will be 5/8"-3/4" - the 1/2" material is just too thin and flimsy, and prone to flaking.
This was my very first build using a (entry level) table saw and cutting a cabinet from scratch, and believe me, the flaws are there, but I'm still happy with the outcome - the overall look was exactly what I had in mind.
I actually cut the driver and port holes with hole cutters, and then used craft plywood for the driver "recesses," cutting them with a rotary tool and a Dremel adaptor that turns it into a tiny but still screaming plunge router. Yes - next time a real router.
Everything us just painted - three coats of hand-applied satin interior light grey latex (paint + primer), and the 3mm plywood pieces just rattle canned with a bit darker grey. Rather than trying to miter the seams I used iron-on white melamine edge banding, which though a bit tricky did a good job of adding some nice clean cosmetic touches.
The drivers are the Dayton Audio (6") RS150T-8 truncated woofers, and the SEAS H1212 tweeters, which I've had for years and carried from build to build. My first more-or-less serious build used these tweeters and the 5" RS woofers, with very good results, and I wanted to get back to this driver combination.
They are ported, 2" x 8" ports in a volume of very approximately 0.35 cu. ft., accounting for interior dimensions, damping material, driver and port volume; expected tuning at around 54 Hz. All recommended from discussions on P.E. They will be working in conjunction with a powered sub, in a modest sized room for which the entire system will be quite adequate for any SPLs I like, and I don't do anything crazy with that.
The XO was done on XSim with help from some experts on a Facebook group I belong to - not perfectly smooth and I will be working on that, but a decent starting point. I have no measuring mic etc. and that + software will be my next investment; though I have a room EQ engine on my A/V receiver, I suspect I can do better.
Ultimately I want to go full active XOs with DSP, but for now passive is what I will be working with.
I welcome any/all comments/input/recommendations.
Thank you for taking the time to read.
It's been literally years since I posted here, but I thought I'd share my latest effort.
Disclaimer: still finishing the build - have not listened to them yet.
I call these the "AluMinis" after the driver diaphragm materials and the compact nature of the cabinet dimensions.
The basic goal was a simple yet modern-looking, small footprint, full-range 2-way speaker with high-value drivers. The cabinets are only about 5.5" wide, 32" tall and 10" deep; straight on they take up very little visual space. I used 1/2" mdf - in the future it will be 5/8"-3/4" - the 1/2" material is just too thin and flimsy, and prone to flaking.
This was my very first build using a (entry level) table saw and cutting a cabinet from scratch, and believe me, the flaws are there, but I'm still happy with the outcome - the overall look was exactly what I had in mind.
I actually cut the driver and port holes with hole cutters, and then used craft plywood for the driver "recesses," cutting them with a rotary tool and a Dremel adaptor that turns it into a tiny but still screaming plunge router. Yes - next time a real router.
Everything us just painted - three coats of hand-applied satin interior light grey latex (paint + primer), and the 3mm plywood pieces just rattle canned with a bit darker grey. Rather than trying to miter the seams I used iron-on white melamine edge banding, which though a bit tricky did a good job of adding some nice clean cosmetic touches.
The drivers are the Dayton Audio (6") RS150T-8 truncated woofers, and the SEAS H1212 tweeters, which I've had for years and carried from build to build. My first more-or-less serious build used these tweeters and the 5" RS woofers, with very good results, and I wanted to get back to this driver combination.
They are ported, 2" x 8" ports in a volume of very approximately 0.35 cu. ft., accounting for interior dimensions, damping material, driver and port volume; expected tuning at around 54 Hz. All recommended from discussions on P.E. They will be working in conjunction with a powered sub, in a modest sized room for which the entire system will be quite adequate for any SPLs I like, and I don't do anything crazy with that.
The XO was done on XSim with help from some experts on a Facebook group I belong to - not perfectly smooth and I will be working on that, but a decent starting point. I have no measuring mic etc. and that + software will be my next investment; though I have a room EQ engine on my A/V receiver, I suspect I can do better.
Ultimately I want to go full active XOs with DSP, but for now passive is what I will be working with.
I welcome any/all comments/input/recommendations.
Thank you for taking the time to read.
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Try plywood it is better than MDF. 12mm is a bit skinny to work with but will outdo 15mm MDF. We built out microTowers with 15mm BB.
If you modeled the tuning with a BR modeler it will be off as the geometric configuation of thes eassuredly makes them ML-TLs.
I’d be very temped to trim the tweeter bezel to be closer to the woofer.
dave
If you modeled the tuning with a BR modeler it will be off as the geometric configuation of thes eassuredly makes them ML-TLs.
I’d be very temped to trim the tweeter bezel to be closer to the woofer.
dave
p10 I'll try plywood on my next project - LOL these are built.
I didn't model the tuning, I just used a recommendation from P.E. The XO is based solely on the drivers - I am a novice doing anything else and welcome some guidance on, as I said, BSC, phase, diffraction, etc. I've been getting to know Vituix but the enclosure section, um, baffles me.
Trimming the tweeter flanges is not an option for now - I'm going to stick with the flanges nearly touching each other.
I didn't model the tuning, I just used a recommendation from P.E. The XO is based solely on the drivers - I am a novice doing anything else and welcome some guidance on, as I said, BSC, phase, diffraction, etc. I've been getting to know Vituix but the enclosure section, um, baffles me.
Trimming the tweeter flanges is not an option for now - I'm going to stick with the flanges nearly touching each other.
I’m no longer familiar with the level of expertise on PE. If ML-TL was not mentioned it was probably treated as a BR which it will not be, The vent typically needs to be longer (or smaller diameter) to tune them lower.
dave
dave
Another thought is to decrease the midpoint of the graph in Xsim vertical scale. This will help you see the breakups and things if they are attenuated enough.
What I see is the spike at 6.1kHz in the rolloff of the woofer. Magnitude is 63dB, and the tweeter is at 85dB. This means the woofer breakup is not attenuated beyond the minimum of -25dB from nominal level as it's only at -22dB. I'm pretty sure this is audible, and will fatigue the listener quite readily. Most builders/designers adhere to the -40dB attenuation spot to get it further suppressed and not such an issue.
To remedy the situation, I would step up the lowpass coil a bit to reduce the magnitude and bring it in line with the tweeter output; say 1.2-1.5mH should do the trick. This will also provide a bit more BSC. Once that is done, the breakup might be -25dB down and not as noticeable. If it's still piercing, then you can:
A- add another smaller series coil after the 22uF cap and make it a 3rd order electrical rolloff.
B- add a series LC placed across the woofer terminals to suppress the breakup completely. I'd estimate a 0.1mH and 8.2uF cap should suffice.
Later,
Wolf
What I see is the spike at 6.1kHz in the rolloff of the woofer. Magnitude is 63dB, and the tweeter is at 85dB. This means the woofer breakup is not attenuated beyond the minimum of -25dB from nominal level as it's only at -22dB. I'm pretty sure this is audible, and will fatigue the listener quite readily. Most builders/designers adhere to the -40dB attenuation spot to get it further suppressed and not such an issue.
To remedy the situation, I would step up the lowpass coil a bit to reduce the magnitude and bring it in line with the tweeter output; say 1.2-1.5mH should do the trick. This will also provide a bit more BSC. Once that is done, the breakup might be -25dB down and not as noticeable. If it's still piercing, then you can:
A- add another smaller series coil after the 22uF cap and make it a 3rd order electrical rolloff.
B- add a series LC placed across the woofer terminals to suppress the breakup completely. I'd estimate a 0.1mH and 8.2uF cap should suffice.
Later,
Wolf
Optimum Cabinet Size (determined using BassBox 6 Pro High Fidelity suggestion)
Sealed Volume 0.13ft³
Sealed F3 101Hz
Vented Volume 0.31ft³
Vented F3 58Hz
Sealed Volume 0.13ft³
Sealed F3 101Hz
Vented Volume 0.31ft³
Vented F3 58Hz
WT thanks so much - again, I'm a novice at this - I assumed the summed FR was the only one to worry about, and that the spike with the woofer was essentially moot.
But now everything you said makes perfect sense. So I have some more modeling to do.
Glad I came here for advice.
But now everything you said makes perfect sense. So I have some more modeling to do.
Glad I came here for advice.
Honestly, you've already failed there, the feet at the base take up the footprint dimensions of a speaker that can feature a 20 or even 25cm (8-10") bass driver. 😉 😛 😀
The drivers got high potential but just from the looks or the drivers it does not make a good speaker. You need to measure and design a crossover or a dsp setup.
Every simulation saves a ton of measurements and effort - but is only as good as its foundation of initial measurements of the drivers. If the measurements were taken in a different enclosure, they will likely not apply to your project. There are ways to simulate the speaker without measurements in your box but every simulation is only as good as its source measurements or in other words, how good and relatable their underlaying data is.
I'm quite confused. You want to do the easy work after you've done the hard work?! 😕 Your speaker will not sound the same active as the passive version, alone from the fact that your serial resistance of the coil(s) in the bass increase the Qt of the midbass driver in that enclosure. A passive version will need a larger enclosure than active if you want to replicate the speaker in a different version but it will go deeper and 'boomier' and a lot less precise.
With a DSP you'll have tons of more options to get to a working setting which you can't reasonably recreate with a passive xo.
To be constructive in critics: In your simulation you've not entered the serial resistance of the choke L2. Since there are none R0 chokes, your simulation is wrong and can't be realized like it's shown on it. You should use a different value anyway, the hunch at 1,7k and drop above it will sound quite dominant and unpleasant. Try 1 or 2 values higher than that for L2.
I don't know the simulation program but it looks like it only simulates the electrical phase and not the acoustical one. If that proves to be correct, you'll have to change the xo fundamentally. I don't think you'll have to change things anyway because you've only simulated the 0° response and ignored the off-axis response, which is more important because the room reflections add up to the tonality even when listening at 0° and you'll likely not always listen at 0° anyway.
I'd strongly suggest you'd decide first if you want to go active or passive, before starting.
The dispersion and linearity will improve with beveled or rounded baffle edges. But well, you've already finished the speakers - which you should not do until the XO is finished and actually works with the enclosure and driver placement. That's why prototypes are a thing and painting, varnish etc should definitely not be done before you are sure it sounds the way you actually want. Dispersion is one of the few things you can not solve with any DSP.
Plywood got a much lower density and therefore resonates much easier than MDF. Plywood is therefore only better than MDF if the enclosure is enforced with ring and/or cross braces. That eats up the weight advantage (if you want to pack them up and use the speakers in a lot different locations) and
the edges are difficult because the layers will show even with paint on them. On the other side the layers of the board can be a nice design element and the wood could be be attractive when visible. Plywood is a lot more expensive though.
It's a ton more enjoyable to work with plywood and it doesn't wear the tools as MDF (by far).
Anyway, he already got the enclosures ready and done so it's not like he can change the material afterwards anyways.
You know you can (and should) vary the enclosure volume in a fairly broad range for most drivers and not fixed to a certain value? In 15l with a 0,6 Ohm choke resistance you can reach 44Hz f3 absolutely clean? And 40Hz with a tad drop which can be compensated by a placement a bit closer to the wall (~20cm)?
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No - the small footprint is also the visual footprint of the cabinet from the front.
As I mentioned, those things are all pending.
I will be measuring properly once I have the equipment - I mentioned that in my post. These speakers were physically designed to look pleasant in a small and highly "decored" room - they are intended to be a part of/blend in to it. This was a known design compromise from the start and I will tweak them as much as possible to compensate for that.
I'm sorry you're confused. I have limited resources. You're a bit condescending.
Yes - but I can't afford all that yet. I have a ton of passive components.
Thank you, that is constructive. I'll see if I can enter those values in the program, but I'd always assumed there was some built-in approximation. What software do you use?
As I said, passive for now - active will require amplifiers I cannot currently afford.
I'm sure that's true, but again there are necessary compromises. I don't know enough about the software to accommodate for off-axis responses. It doesn't tell you much. Vituix is more sophisticated but I am technically illiterate and always have trouble following the instructions. This is a basic reason i have a lot of challenges in speaker design.
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It is a really bad choice to let them run that low with a subwoofer below it because you'll get a huge group delay increase with a that low xo to the sub. In fact, you'll already get a much more precise sound reproduction in a sealed and not a ported speaker.
E: Even sealed you can go lower than the suggested enclosure.
I would honestly prefer ppl not to post in a public forum if they can't stand their proud constructions being commented/criticised. That's the charakter of a forum and since the critics were most constructive ones, I'd expect them to be the most helpful. Again, if you don't want such replies, maybe it's better not to post them on a public forum. So if you don't want such replies and just want amazed in awe reactions, maybe move over to maybe facebook or IG instead and not post on forums made for information and ideas excange and not post here anymore, thank you.
Oh, how so? What's wrong with what I said? Just that you don't like what's physics? Well, yes, then I indeed did it the wrong way. But you did too because physics does not reward things you think are right. And physics doesn't care if you don't like where your approach to speakers (or acoustics in general) might have holes or be wrong completely. Good luck with your speakers, I think you might need that since feeding sims with inaccurate data will not help at all. Physics doesn't care if you think it has to be correct another way.
Have a nice day, gl with your speakers.
I don't believe these small issues will be a problem.. but if you have the need, an equaliser (old, new, computer based) can help you make adjustments.