GM, could you reduce the line length at all and still not have to change the port and everything else? I was thinking of making it 48" instead of the 50.75" it would make it easier to cut it out of a sheet of plywood. Otherwise you need 4 sheets of plywood just to get the 28.5" boards out of it.
Scottmoose said:
Greets!
Yes, Hornresp, I haven't 'tackled' Akabak yet, which is probably more accurate and far sure more flexible. AFAIK Hornresp is much too limited to design a tapped horn as I would like.
Thanks! Huh! Never heard of it and I'm a sci-fi fan.
Yeah, acoustically small boxes sound, well, 'small', but the bottom line is that I recommend alignments based on acoustic solutions for potential acoustic problems in that attenuating a speaker reduces distortion and boosting increases it, though how audible it may be depends on too many variables to put a number on it.
WRT the in-room sim comparison, they look /'trend' nothing like any I've ever measured for a 30" wide baffled T/S max flat alignment ~against a wall using a 1/3 octave RTA/pink noise at the listening position, so absent any more accurate measurements I have no faith in it for even comparison purposes. As always though, YMMV.
WRT SAF speaker size issues, forum rules preclude me from expressing most of my thoughts on the subject, but apparently the women outside the society 'bubble' I inhabit either have little interest in 'experiencing' music at any visceral level and/or their men make no attempt to contour a speaker system's response to their generally more acute (sensitive) hearing and how LF impacts their senses. I'm betting on the latter since live concerts typically have more women than men attendees and a little research will reveal B$%&'s popularity has as much or more to do with how they sound than how compact/'cute' they are.
GM
Yeah, it disappeared for some reason. Made in 1983 IIRC. I only know it myself because I'm a fan of Christopher Lee's work. (The Wicker Man for e.g. -greatest horror film ever made IMHO. I normally give the nod to Stanley Kubrick's work, but for once, in this genre, I think he was outdone, great though The Shining is).
I've an ominous feeling you're right on the SAF / B£$e front Greg. My ex has a pair of BIBs I built, and an opera-singer friend has a pair of Martin's ML TQWTs, which are pretty large by UK standards, and both love them. They could be exceptions though. Still, I have one rule about SO's: that they know this is my interest, and I'm not being dictated to about my speakers. I'll make sure their prettified, and of course I'll indulge them their interests, but the 'you can't bring a pair of cabinets that large into my living room' argument doesn't get a look in. It's my living room too.
Re the shortening, it'd probably need adjusting as the height of the cabinet (i.e. the line length) determines the tuning frequency, and you'll be loosing some volume from the cabinet.
I've an ominous feeling you're right on the SAF / B£$e front Greg. My ex has a pair of BIBs I built, and an opera-singer friend has a pair of Martin's ML TQWTs, which are pretty large by UK standards, and both love them. They could be exceptions though. Still, I have one rule about SO's: that they know this is my interest, and I'm not being dictated to about my speakers. I'll make sure their prettified, and of course I'll indulge them their interests, but the 'you can't bring a pair of cabinets that large into my living room' argument doesn't get a look in. It's my living room too.
Re the shortening, it'd probably need adjusting as the height of the cabinet (i.e. the line length) determines the tuning frequency, and you'll be loosing some volume from the cabinet.
davidallancole said:
Greets!
To maintain the same simmed response, yes, so for the record:
L = 48"
CSA = 134.685"^2 ( prefer 28.5" W x 4.47" D)
zdriver = 18.637"
zport = 4" dia. x 1.75" long near/at the bottom for T/S max flat
All dims i.d. and approximate, minimal stuffing and add more down at/in the vent if too 'boomy'. Driver mass loaded against the back panel.
GM
Attachments
B20 MLTL
I actually did build a MLTL with the B20 several years ago when I first started playing with full range speakers. The B20 works very well in a MLTL, giving good base response down into the low 30's/upper 20's. I used Martin Kings spreadsheets to do the design work and the responses looked a lot like the ones Scottmoose posted. I ended up using a tweeter since I found that the B20 didn't have good high end extension, and has a few sins in response that I was able to avoid. All in all a nice sounding speaker. I'll try to dig up and post my design details for you to look at them.
PJN
I actually did build a MLTL with the B20 several years ago when I first started playing with full range speakers. The B20 works very well in a MLTL, giving good base response down into the low 30's/upper 20's. I used Martin Kings spreadsheets to do the design work and the responses looked a lot like the ones Scottmoose posted. I ended up using a tweeter since I found that the B20 didn't have good high end extension, and has a few sins in response that I was able to avoid. All in all a nice sounding speaker. I'll try to dig up and post my design details for you to look at them.
PJN
Now i cant decide which to build next for the B20, the BVR (Half Chang) or one of these BRs?
But i do enjoy B20s in sealed boxes. Been a few years so they need an update. I do like how the BVR can accept a Fostex substitute for a future upgrade.
http://www.zillaspeak.com/pioneerb20-piezo.asp
Boy do they look ugly on screen. But they look nice with their grills on tucked away in the corners of my office. I must have these at least 5 years and the foam shows no sign of wearing out. Comparing these sealed speakers to the BIBs shows how small speakers can sound in comparison to high efficiency back horns of sorts.
Godzilla
But i do enjoy B20s in sealed boxes. Been a few years so they need an update. I do like how the BVR can accept a Fostex substitute for a future upgrade.
http://www.zillaspeak.com/pioneerb20-piezo.asp
Boy do they look ugly on screen. But they look nice with their grills on tucked away in the corners of my office. I must have these at least 5 years and the foam shows no sign of wearing out. Comparing these sealed speakers to the BIBs shows how small speakers can sound in comparison to high efficiency back horns of sorts.
Godzilla
renfrow said:
Just remember that Nelson modified the dimensions and posted it two pages later. You can find the new dimensions right here.
Thanks for the responses guys.
I wouldn't mind seeing what you did Nortp if you don't mind digging it up. Can you elaborate on the few sins in the response and how you avoided them?
Whats that piece of wood you have glued on the front of your box Godzilla? Is that to help dampen some of the resonance from the box? If so, would that work on this larger box that GM has proposed? Do you have the front bolted to the back? There looks like there is some screw heads or something a little further out from the speaker.
I wouldn't mind seeing what you did Nortp if you don't mind digging it up. Can you elaborate on the few sins in the response and how you avoided them?
Whats that piece of wood you have glued on the front of your box Godzilla? Is that to help dampen some of the resonance from the box? If so, would that work on this larger box that GM has proposed? Do you have the front bolted to the back? There looks like there is some screw heads or something a little further out from the speaker.
Some info on my B20 MLTL
David,
It's been a few years and I can't find any info on the crossover that I used, but here is what info I have been able to dig up.
Box dimensions (external) : H = 43", W = 10.5, D = 15.
The woofer centerline is at 36", the tweeter centerline is at 29 3/4", tweeter centerline is 3" from inside edge of enclosure. I mage the box out of 3/4" MDF. I also ended up removing the whizzer when I added the tweeter. I'll attach series of pictures showing some measurements, you'll notice that the B20 has some serious irregularities a little above 2K. I crossed 2nd order at ~ 2K to try and avoid them. The tweeter is the PE silk dome. The pic below show the finished project, they've been my garage speakers for about four years now. They sound good enough to be in the house it's just that I didn't sweat the details on the enclosures. The fuzzy stuff on the baffles is felt, I added there for diffraction control. All actual measurenents were done with the B20 mounted in the enclosures outside on the driveway, no smoothing applied. Ignore everything below ~ 200 Hz. The base is very nice, no boom, just tight and deep.
PJN
David,
It's been a few years and I can't find any info on the crossover that I used, but here is what info I have been able to dig up.
Box dimensions (external) : H = 43", W = 10.5, D = 15.
The woofer centerline is at 36", the tweeter centerline is at 29 3/4", tweeter centerline is 3" from inside edge of enclosure. I mage the box out of 3/4" MDF. I also ended up removing the whizzer when I added the tweeter. I'll attach series of pictures showing some measurements, you'll notice that the B20 has some serious irregularities a little above 2K. I crossed 2nd order at ~ 2K to try and avoid them. The tweeter is the PE silk dome. The pic below show the finished project, they've been my garage speakers for about four years now. They sound good enough to be in the house it's just that I didn't sweat the details on the enclosures. The fuzzy stuff on the baffles is felt, I added there for diffraction control. All actual measurenents were done with the B20 mounted in the enclosures outside on the driveway, no smoothing applied. Ignore everything below ~ 200 Hz. The base is very nice, no boom, just tight and deep.
PJN
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