Sheesh! Terrible typo !
New speaker design by NOOB
- Thread starter Adam Frandsen
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swpaskett
Well-known member
Since you are willing to dump serious money into this project, have you considered an active xover, maybe one of the nice DSP units available now. It has been a while since I have looked into them, but I was quite intrigued by the tweakability of some of these units. Even if that is not your final destination it would provide you with a way to test your system without building and tweaking many variants of a discrete xover. You should also plan on building and rebuilding those cabinets multiple times; the first is never satisfactory.
One of the best sounding speakers I have ever heard was a particle board box with an Altec 604 duplex speaker stuffed into it. The guy who built it said it was his 23rd iteration on the cabinet. It was put together with nails and caulk -- no glue so he could knock it apart and rebuild it quickly. The crossover was a single capacitor. That was back in the '60s -- when 50 Watts was a lot of power, hum and hiss was how you knew the final was on and T-S wasn't even a dream yet, but had it been around I doubt it would have led to this box. Good speakers are still more art form than mathematics.
But setting that aside, have you ever built a speaker before? Most people start out building 2-way bookshelf speakers and taking on the learning curve gradually, not trying to build a Rolls Royce on their first gambit. Putting a couple toes in the water first can save you time and frustration in the long run, especially if you don't know how to swim.
I realize I am throwing water on an oil fire...
And here I go being verbose again. Forgive me, I've been away a while.
One of the best sounding speakers I have ever heard was a particle board box with an Altec 604 duplex speaker stuffed into it. The guy who built it said it was his 23rd iteration on the cabinet. It was put together with nails and caulk -- no glue so he could knock it apart and rebuild it quickly. The crossover was a single capacitor. That was back in the '60s -- when 50 Watts was a lot of power, hum and hiss was how you knew the final was on and T-S wasn't even a dream yet, but had it been around I doubt it would have led to this box. Good speakers are still more art form than mathematics.
But setting that aside, have you ever built a speaker before? Most people start out building 2-way bookshelf speakers and taking on the learning curve gradually, not trying to build a Rolls Royce on their first gambit. Putting a couple toes in the water first can save you time and frustration in the long run, especially if you don't know how to swim.
I realize I am throwing water on an oil fire...
And here I go being verbose again. Forgive me, I've been away a while.
Disco Volante
Well-known member
This just looks downright weird/wrong. You can't just cascade two identical filter stages that way.
For starting out on speaker building, I suggest Troels Gravesens website. Not only does he do kits, but also explains some basics. Plenty resources (and nonsense) to be gather éd online...
I suggest getting a basic measuring mic and an impedance rig set up, plus relevant software, like REW. Maybe have a look at VituixCAD?
Good data is imperative to making good crossovers...
Happy Tinkering
I’d also be careful regarding stacking capacitors and inductors in series/parallel to get the values you want. Sometimes it’s better to wind your own inductors and use cap values that fall within preferred value ranges - ie shift your crossover points to sit within capacitor values available and then wind inductors to match. You can get weird responses when stacking capacitors.
Adam Frandsen
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All your suggestions I will take into account, maybe I can use it as you say to tweak and test, a DSP won’t be in my final design though. I have built a subwoofer before, not that it is really the same. I am now thinking about some cheaper drivers for this first build…
Adam Frandsen
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All in all I am back at the drawing board and reading up on more incl. VituixCAD
That is a surprizing assertion. In 60 years I have never seen it happening. Paralleling/serializing capacitors is pretty predictable.
Capacitors of differing values each have their own reactance to various frequencies - when you end up with a net value it will have a known effect but there are individual filtering effects that colour the sound when using caps of different values in parallel - also caps in series will increase the ESR of that section of a filter network. Phase relationships of different value caps in parallel may not match as their charge times will differ so they will tend to crossfeed.
These effects happen typically at frequencies above 50kHz for electrolytics and much higher for film or ceramic caps. We're talking about audio frequencies here.
Of course, but typically, connecting two 100uF caps in series will result in the same ESR as that of a 50uF of similar technology. ESR is roughly inversely proportional to capacitance. Again for similar technology.
Don't worry, Kichhoff is taking care.
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k brown
Well-known member
I will only add (FWIW) that after (too many) years of mucking about with DIY speakers, the only things that were remotely successful sound-wise, were single full-range drivers in simple enclosures, and two-way designs that were bi-amped with 4th-order Linkwitz-Riley crossovers.
Successful passive crossover design (especially three-way or more) can be a very fraught enterprise.
Successful passive crossover design (especially three-way or more) can be a very fraught enterprise.
Not to feed the veer but the best sounding general purpose universal 2-way crossover (designed for an amplifier plug-in accessory) that I experienced, used a staggered pole filter alignment that uses a simple one-pole response in the sensitive crossover region for minimal phase issues between drivers. Additional poles away from the crossover point add more protection without phase problems.
===
LR alignment is popular for high power sound reinforcement systems because both pass bands are down -6dB (1/4 power) at crossover point for extra driver protection. The phase rotation has gone all the way around to 360' that behaves like 0' with summed sine waves .
JR
Adam Frandsen
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I do not understand why I cannot find a single driver from a single manufacturer that has IMD numbers in their spec sheets, this seems to me the single most important value one would need to determine the quality of the driver, no?
I'm not the speaker guy here but there are a few specifications probably considered more important to speaker manufacturers/users.
1- frequency response
2- sensitivity
3- power handling
JR
jensenmann
Well-known member
Another important thing to look at is how many resonances are visible in the impedance curve besides the resonance frequency. Any other bump in the curve is created by mechanical resonances which will translate in a more uneven frequency response and eventually in ringing (visible in a waterfall plot).
IMD being dependant on the combination of several frequencies, the actual result depends very much on how the loudspeaker is used, particularly the range of frequencies.
Just a simple example: typical IMD measurement implies mixing a low frequency (50 or 60Hz) with a HF tone (typically 7kHz).
Applied to a woofer, the 7kHz signal is very low, so the modulated signal is bound to be difficult to measure, when applied to a tweeter, it will be (ab)used so much outide its nominal range that the results will be horrific. In these conditions, no manufacturer wants to publish these results.
DFD wouldbe a better assessment of performance though, but will also be of limited use, since measurements have to be adapted to the particular nominal range of the speaker, so no specs would be comparable.
Loudspeakers are actually kind of "3D" apparatus, so can't easily be described by single parameters.
IMD varies almost exponentially with level, so the designer has some leeway as to how he wants to use the loudspeaker. Using two speakers instead of one can result in seriously improved IMD.
MidnightArrakis
Well-known member
[As mentioned I tried easyEDA, but must be doing something wrong] -- If you can -- CLEARLY -- draw your schematic out on paper and take a -- GOOD -- photo of it, then send me a PM with your schematic photo and I will create one for you using one of my 3 schematic CAD-programs!!! Sound like a plan???
Be certain to use all of the proper symbols and notate all of the component values, voltages, wattages, etc.
/
S.Samuelsson
Active member
Hi.
VituixCAD
Just shows that it's been a sweet while since I last looked at the more up to date and more comprehensive speaker- and x-over design programs, and when I first saw that name, I thought that it HAS TO be a program written by a Finn.
Or there's a tongue-in-the-cheek Finn on the team.
And sure enough, a Finn is behind that code.
Not that I particularily need to revisit a hobby that's been on idle for a few decades for a several good reasons, but that piece of software looks so good with a quick glance that I have to try it out sometime in the near future.
Perhaps design something around the Seas P17 and P21 REX:es and Dynaudio D-28:s along with other drivers I have stashed away
.
And some marble, granite and soapstone as well....
Regards,
Sam
VituixCAD
Just shows that it's been a sweet while since I last looked at the more up to date and more comprehensive speaker- and x-over design programs, and when I first saw that name, I thought that it HAS TO be a program written by a Finn.
Or there's a tongue-in-the-cheek Finn on the team.
And sure enough, a Finn is behind that code
.Not that I particularily need to revisit a hobby that's been on idle for a few decades for a several good reasons, but that piece of software looks so good with a quick glance that I have to try it out sometime in the near future.
Perhaps design something around the Seas P17 and P21 REX:es and Dynaudio D-28:s along with other drivers I have stashed away
.And some marble, granite and soapstone as well...
.Regards,
Sam
Adam Frandsen
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Wow - thanks
I am doing some more research at this stage and recalculating everything, I am even considering using cheaper drivers for the build, but nothing is final yet. I just realized I need to put more time into this, so I am sure to get a good result. Once I am further in the process, I may well draw upon your resources, thank you so much for being so generous!!
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Adam Frandsen
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I understand these are of course essential, but what does a frequency response mean if the speaker cannot maintain its individual frequency linearity when more frequencies are played simultaneously - which in praxis would be all the time.
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I tried to search "praxis" and apparently I can't help you...
Good luck.
JR
Good luck.
JR
