Hi.
I have this project, where i got a have around 20 liters, in which the 18W/8531G00 fits perfectly. I got a great deal on one used - about 55 dollars, so I bought it - Scanspeak suggests 23 liters themselves for a sealed cabinet.. I cant however decide, if I should go for a sealed or ported enclosure. Its going to be crossovered at 1000 hz 2nd order.
I don't really have experience in using a much smaller cabinet than suggest ported, so I don't know if i should just skip it and use the sealed one. I also considered using a passive radiator in which i got approx. the same response as the ported here.
Thanks!
I have this project, where i got a have around 20 liters, in which the 18W/8531G00 fits perfectly. I got a great deal on one used - about 55 dollars, so I bought it - Scanspeak suggests 23 liters themselves for a sealed cabinet.. I cant however decide, if I should go for a sealed or ported enclosure. Its going to be crossovered at 1000 hz 2nd order.
I don't really have experience in using a much smaller cabinet than suggest ported, so I don't know if i should just skip it and use the sealed one. I also considered using a passive radiator in which i got approx. the same response as the ported here.
Thanks!
I realize you may not want a significantly larger cabinet, but I built a 2-way with the same woofer in a mass-loaded TL that came out really, really good. I've attached a 1-page "highlights" of it. It won the Over-$200 category in the 2017 Parts Express Speaker Design Competition.
Paul
Paul
Hi Paul.
Thank you for showing me! I wish i could make it like yours! Unfortunately im building this for a friend, who has a pretty tight space, and therefore wishes it to around the 22 liter mark.
Thank you for showing me! I wish i could make it like yours! Unfortunately im building this for a friend, who has a pretty tight space, and therefore wishes it to around the 22 liter mark.
I've designed and built plenty with this driver from 13 litres (mid), 18 to 37 litres midwoofer). I did try sealed on some designs but vented tended to get more out of the design.
The 18W8531G00 does have it's issues such as it can do great deep bass and mids but not at the same time. Removing deep low bass from this driver pays off in the mids. The usual vented modelled box size of 37 litres is just too large and found 20-22 litres with the F3 over 40Hz the best when used as a midwoofer. There are other upsides to the smaller box but one can see that in the modelling.
Troelsgravesen came to a similar conclusion and there was a post by the Revelator designer who stated the smaller vented box (22-24 litres IIRC) was a better solution. An example is Madisound has a list of box sizes and one is 21 litres, Ø51 x 165 port, F3=41Hz.
The 18W8531G00 does have it's issues such as it can do great deep bass and mids but not at the same time. Removing deep low bass from this driver pays off in the mids. The usual vented modelled box size of 37 litres is just too large and found 20-22 litres with the F3 over 40Hz the best when used as a midwoofer. There are other upsides to the smaller box but one can see that in the modelling.
Troelsgravesen came to a similar conclusion and there was a post by the Revelator designer who stated the smaller vented box (22-24 litres IIRC) was a better solution. An example is Madisound has a list of box sizes and one is 21 litres, Ø51 x 165 port, F3=41Hz.
Have a look at the write up for the Zaph ZRT he has a 38l ported and a 20l sealed option using the same driver.
http://www.zaphaudio.com/ZRT.html
http://www.zaphaudio.com/ZRT.html
Thanks a lot, that is very useful! 21l would be perfect for me, ill check troels' discoveries out aswell.
Ported for maximum output, sealed for sound quality. It really is that simple.
I know it can be that simple, but I just wanted to know how people thought it sounded when it was playing sealed vs ported.
My experience with this driver in my Brioso design has been great in its' 49-liter MLTL and the PE judges at the 2017 contest agreed as did many of the other attendees. I realize my ears are not other people's ears nor are our likes in music necessarily the same, but I just don't/can't buy that this SS midwoofer can't play below 40 Hz without sacrificing its midrange performance. I'm going to attach a copy of my article about this design that was published in the September, 2018 issue of AudioXpress magazine (I hope it isn't too large).
Paul
Paul
Apologies, I just noticed that you're using this up to 1kHz. Any small driver like this is incapable of reproducing deep bass at any meaningful level, and will compromise the midrange in trying to do so due to the extreme cone displacement.
Furthermore, the port in the article above is considerably undersized.
Furthermore, the port in the article above is considerably undersized.
I have a pair of the 4-ohm versions in ported cabinets. While there's only so much you can do with 6.5" drivers in terms of absolute output I have to say that these drivers have very credible bass output. Plenty for most Jazz recordings out there. The right room however is well treated and relatively modest.
I went with optimally flat, and kind of regret it though, a smaller ported cabinet would have probably been better. A sealed cabinet may also be good with the right reinforcement from the rear wall.
Also, that crossover point seems low. You can do higher really easily. The official ScanSpeak FR measurements are not wrong, per se, but close miced and make it sound harder to implement a higher crossover than you would otherwise. I have mine crossed over 2 kHz and they did really well with a minimum of fuss though tid take some hand tweaking of the LP filter. Also helps if you let your crossover design be more guided by 1m measurements instead of close.
I went with optimally flat, and kind of regret it though, a smaller ported cabinet would have probably been better. A sealed cabinet may also be good with the right reinforcement from the rear wall.
Also, that crossover point seems low. You can do higher really easily. The official ScanSpeak FR measurements are not wrong, per se, but close miced and make it sound harder to implement a higher crossover than you would otherwise. I have mine crossed over 2 kHz and they did really well with a minimum of fuss though tid take some hand tweaking of the LP filter. Also helps if you let your crossover design be more guided by 1m measurements instead of close.
I am not seeking deep bass either. For the use that its gonna get here, I think an f3 of 40-45 would be great for the music she listens to.
Is there anyone who has experience with the bass in a closed cabinet? Would be fun to see.
The crossover corner is ~2.1 kHz, not 1 kHz which you would have realized if you read the attachment I provided in Post #2. As to the port's size it is not undersized much less considerably so. When the system is generating 100 dB SPL at 1 meter, the peak port air velocity is not quite 21 m/s at ~22 Hz where there is usually little musical content, while at the same time the woofer's excursion doesn't exceed Xmax+15% from 22 Hz on up. Your statement about this driver not being able to reproduce deep bass at any meaningful level is incorrect.
Paul
I've done this woofer in a 32 liter cabinet ported and it's amazing. This woofer will do low frequencies and mid-range just fine. If you are able to model this driver in a smaller cabinet to determine the best port size then it will work out. There will be some compromises since it's a smaller cabinet but if you're making them for a friend and this is the size limitation then I don't see anything wrong with it. Every build doesn't have to be perfect. There will always be compromises and I think this driver will do just fine in a cabinet like that. I would still port it to extend the low end. Just make sure you get the port as correct in size as possible.
#ThatSoundsGood.
Yeah, that is what im thinking. My friend is coming from something like a cheap 4inch speaker, but appreciates good sound. I want to make it sound good, but i really dont think that they need very deep bass.. I guess i should go vented as it seem like everyone has done that with this driver.. At least in an application like ths.
Thanks
Yeah, that is what im thinking. My friend is coming from something like a cheap 4inch speaker, but appreciates good sound. I want to make it sound good, but i really dont think that they need very deep bass.. I guess i should go vented as it seem like everyone has done that with this driver.. At least in an application like ths.
Thanks
I was also wondering how much you guys worry about 1st port resonance when building stuff like this? If i say want a crossoverpoint around 1000 hz and pick a 2" / 5 cm vent, the 1st port resonance is around 1000 hz and has a port air velocity that can get pretty high.
I guess what im asking is how worried i should be about 1 port resonance when building ported midwoofers.
I guess what im asking is how worried i should be about 1 port resonance when building ported midwoofers.
With a midrange output of 100dB, the 40Hz output would need to be around 120dB to sound equally loud (Fletcher Munson curve), so my comment stands.
Further, the BL non-linearity even at, let alone exceeding Xmax is going to horrible things to the midrange. Expecting a tiny driver to reproduce good sound up to 2kHz whilst flapping about at Xmax or more trying to reproduce 22Hz remains somewhat optimistic... Correct port dimensions and design would increase output and reduce distortion considerably.
MrKlinky, if you didn't live in Europe I'd invite you to come take a listen to the Briosos while playing classical symphonic music with its typically wide dynamic range. I don't happen to listen to music where the average SPL is 100 dB at 1 meter, more like 80 dB at my ears in my sweet spot recliner which creates a reasonable replica of what I hear in a concert hall. I've been designing and building TL-based speakers for over 2 decades and what you're saying about the port's dimensions and overall design of the Brioso is not correct or factual.
Paul
Paul
My statement was: "Correct port dimensions and design would increase output and reduce distortion considerably."
The corollary to this is: Correct port dimensions and design would reduce output and increase distortion considerably.
Which will it be?