had je geen dsp? dan zou ik geen basreflex doen - lijkt met dat je op lekker geluidsniveau wel wat speelruimte hebt om je woofer in gesloten kast onderin te boosten met dsp
I can postpone putting in the ports. Test everything and listen and then convert to ports and do it again. That's the benefit of prototyping.
I initiially went for high efficiency, but I kinda let that go when I opted for bi-amping. Now I will at least have a solid state amp driving the base that has enough power and can still use my tube amp (or not, who knows) for the efficient highs.
ps. It was quite a surprise to read some dutch
My initial thought was that google/chrome/android was autotranslating.
I initiially went for high efficiency, but I kinda let that go when I opted for bi-amping. Now I will at least have a solid state amp driving the base that has enough power and can still use my tube amp (or not, who knows) for the efficient highs.
ps. It was quite a surprise to read some dutch
My initial thought was that google/chrome/android was autotranslating.Tom Kamphuys is not my real name. It's a nickname my friends gave me because my glasses back in the day looked like the one of Kamphuys from De Lullo's by JIskefet. Don't know if that is something to be proud of haha.
Kamphuis is a very common name in Twente (and Hengelo). I actually work in Hengelo. It's a small world after all.
Kamphuis is a very common name in Twente (and Hengelo). I actually work in Hengelo. It's a small world after all.
10e luisterdag Oost Nederland zaterdag 4 februari 2023
https://zelfbouwaudio.nl/forum/viewtopic.php?t=31036this could be a nice day for you then
Hi,
I have not built two way box like this but same stuff applies as with any boxes so a quick comment to get you started on your own research
Member augerpro has published results of many experiments with box damping and ports, look for details.
In general you'd probably want to reduce resonaces as system looks like it could have enough lows without. Resonances on midrange would color the midrange, which I would think is better without. There would also be edge diffraction.
As it is a two way system woofer is required to reproduce both mids and lows which have conflicting interests. Weighty bass would benefit bigger box volune and mids would perhaps be better with smaller one to push resonances out of band, internal modes and resonances of panels. Big panels radiate louder and pass band no matter what. Outside dimensions of the box affects diffraction and bafflestep which go hand in hand.
So its a compromise in this sense, its too big and too small at the same time. To get top performance you probably should make it quite high tech to minimize any ill-effects by all means necessary.
I'd make it kind of small side, reduce lowest internal resonances by positioning the woofer middle of baffle and using at least constrained layer damping bracing and play with stuffing. I would roundover edges if baffle needs to be wider than the driver. I would leave it sealed and consider separate subwoofer(s) system if you find bass lacking or room ruining the response after you have listened to it for a while. Porting is fine but has potential midrange issues and benefit prototyping. Ports become unnecessary if you do add sub(s), so perhaps unnecessary work to go through at this point.
I would optimize the box rather for midrange performance than for bass performance because you can get more bass performance by adding more boxes into the room, but to improve midrange youd need to make better box and might as well do it from the get go. If there is no possibility to add more bass boxes to the system under any circumstances then I would make the box big enough to have nice bass, and port it.
Have fun!
I have not built two way box like this but same stuff applies as with any boxes so a quick comment to get you started on your own research
Member augerpro has published results of many experiments with box damping and ports, look for details.
In general you'd probably want to reduce resonaces as system looks like it could have enough lows without. Resonances on midrange would color the midrange, which I would think is better without. There would also be edge diffraction.
As it is a two way system woofer is required to reproduce both mids and lows which have conflicting interests. Weighty bass would benefit bigger box volune and mids would perhaps be better with smaller one to push resonances out of band, internal modes and resonances of panels. Big panels radiate louder and pass band no matter what. Outside dimensions of the box affects diffraction and bafflestep which go hand in hand.
So its a compromise in this sense, its too big and too small at the same time. To get top performance you probably should make it quite high tech to minimize any ill-effects by all means necessary.
I'd make it kind of small side, reduce lowest internal resonances by positioning the woofer middle of baffle and using at least constrained layer damping bracing and play with stuffing. I would roundover edges if baffle needs to be wider than the driver. I would leave it sealed and consider separate subwoofer(s) system if you find bass lacking or room ruining the response after you have listened to it for a while. Porting is fine but has potential midrange issues and benefit prototyping. Ports become unnecessary if you do add sub(s), so perhaps unnecessary work to go through at this point.
I would optimize the box rather for midrange performance than for bass performance because you can get more bass performance by adding more boxes into the room, but to improve midrange youd need to make better box and might as well do it from the get go. If there is no possibility to add more bass boxes to the system under any circumstances then I would make the box big enough to have nice bass, and port it.
Have fun!
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Make an impedance measurement of the raw driver in free air to compare against the one in the box then you can see which resonances are in the driver and which come from the box.
Sealed and bass reflex need different damping strategies. In a sealed box you can stuff it quite heavily but doing the same in a reflex box will turn it more aperiodic and reduce the port output.
Insulation material used in houses works well for box damping, fibreglass and the more recent polyester types. Polyester is tricky because it does not all behave the same. Pillow stuffing material is next to useless at damping resonances. Ordinary acoustic foam is OK and Basotect or melamine foam is better. Reconstituted felt in a purple or green colour like the type used in car sound absorption works really well. In a reflex, lining some of walls with that or some foam can be a good compromise.
Impedance comparisons of different materials in a closed box
https://www.diyaudio.com/forums/full-range/303417-range-tc9-line-array-cnc-cabinet-post5053920.html
I used three layers of this as felt surrogate for lining all but baffle wall to good effect https://www.ebay.de/itm/250791540095
just cut the lower sectionPretty sure it's not needed
View attachment 1008565
Hi tmuikku,
regarding your post, your paragraph deals with "optimiz[ing] the box" for midrange. Could you please advise, how to optimize it for bass? I do not need the box to reproduce frequency higher than about 400 Hz - 450 Hz.
Kindest regards,
M
regarding your post, your paragraph deals with "optimiz[ing] the box" for midrange. Could you please advise, how to optimize it for bass? I do not need the box to reproduce frequency higher than about 400 Hz - 450 Hz.
Kindest regards,
M
Hi, its bit of a philosphical advice to remind there is always some trade-offs one is dealing with. There is nothing special to it, its just that while calculating box size with box simulator one is mainly dealing with low knee of the system, its Q. This is important because good bass is mandatory, but the simulator doesn tell anything about midrange and how its performance changes as you change parameters. Its designers responsibility to know what he is dealing with and what matters and what not and what is the trade-off if I do this or that, in system level.
For good bass, in my opinion and yours might differ, we need as much cone area as possible, which usually means guite large boxes, which means all kinds of issues with the boxes and drivers get lower in frequency which limits "clean" bandwidth, so midrange performance is getting traded-off just by sound wavelength alone.
It all comes to sound wavelength. Bass is room sized wavelengths has room sized problems and need room sized solutions, so to optimize for bass is to make a big system that deals with the room. This is again just philosophical stuff how to get very good sound reasoning from wavelength, trying to push wavelength related issues out of band, take trade-offs that don't affect system performance (too much). Conversely, if you want really good system it means you haven't sacrificed anything, traded-off anythin important. It is not based on actual listening and experience what sounds good but to reasonable logic to make a problem free system from ground up based on physical property of sound, the wavelength. So just a philosophical guideline. hope it helps
For good bass, in my opinion and yours might differ, we need as much cone area as possible, which usually means guite large boxes, which means all kinds of issues with the boxes and drivers get lower in frequency which limits "clean" bandwidth, so midrange performance is getting traded-off just by sound wavelength alone.
It all comes to sound wavelength. Bass is room sized wavelengths has room sized problems and need room sized solutions, so to optimize for bass is to make a big system that deals with the room. This is again just philosophical stuff how to get very good sound reasoning from wavelength, trying to push wavelength related issues out of band, take trade-offs that don't affect system performance (too much). Conversely, if you want really good system it means you haven't sacrificed anything, traded-off anythin important. It is not based on actual listening and experience what sounds good but to reasonable logic to make a problem free system from ground up based on physical property of sound, the wavelength. So just a philosophical guideline. hope it helps
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I read the thread, watched the videos and am reading his webpage. I'm (again) a bit overloaded with information.
What is the conclusion you guys have drawn? What works? What is worth it?
in the choice between sealed en bassreflex, it is good to undestand the compromise of bassreflex - you can get more bass from the woofer but midrange quality might suffer from that choice - with dsp i would first try a sealed
basreflex is a compromise between bassboost at certain low frequency and midrange quality - the boost is based on delayed output from the backside of the cone
you can use logic with the data, use bracing so that aspect ratio of free panel increases. If you had one brace for panel like in your image, you'd want to put it horizontally on not vertical.See top middle image mode, it would happen if you had vertical brace on the middle that attaches middle of the panel firmly. The panel is now divided in two, whose aspect ratio is about same or bigger than the original and it shows 350Hz mode in this case. If you had horizontal brace instead, aspect ratio of the two panels is now bigger, the left column middle mode would happen, resonance is much higher at 560Hz. Even better, two horizontal braces, even greater aspect ratio, bottom left situation. Lowest mode is now out of band.
This is the difference between in and outside of the enclosure. I did match them globally by adding a constant resistance to one of the two measurements.
labels with first letter at the frequency.
I added labels for resonances that could be close. But there are a lot of peaks and a lot of possible resonances, so they all might just be random coincidences.