Ah! you got me there! All I need is a glance at it plus bjorno usually defines the type of cab alignment a bit more than he did this time, which I didn’t notice.
Correct x 3.
Unfortunately, HR can't do two ‘driver’ offsets except as a ‘tapped’ one, so the vent must be modeled as down-firing, but the WLs are so long it doesn't matter if it's down or front, etc., firing if mounted somewhere within a few inches of the bottom, though if it's located right at the bottom front, etc., i.e. a type of shelf vent, then it physically shortens the vent's end correction for a given tuning due to local boundary loading, same as when floor, wall or corner loading a speaker, which in turn means it will be tuned lower than predicted. Most folks never notice though, due to long WLs unless it’s a pretty high tuning and/or measurements are done [see attached].
Also, with MLTLs, there can be a bit of a benefit in its HF response by moving the vent to the pipe's 4/5th harmonic around ~80% down or 6/7th, ~86%, so you've got some flexibility. In essence, it allows one to use less internal damping, yielding a bit more 'lively' sound [not to be confused with 'boxy'] due to less comb filtering of the vent's pipe harmonics with the driver up into the hundreds of Hz.
If max gain is 'everything' performance wise, then put the driver and vent at the pipe’s two extremes.
Best overall TL/horn design database: Quarter Wavelength Loudspeaker Design
Unfortunately, MJK’s most excellent software is no longer available to accurately model these, but Leonard Audio’s software is easier overall to use since it’s more like HR’s Loudspeaker Wizard and gets ‘close enough’ results in comparison to MJK’s [undamped]: Leonard Audio | Audio Engineering Resources
A MLTL becomes a badly tuned BR when the vent is traditionally located near the driver as this creates a secondary main reflection that causes an audible null in the response in the mid-bass and since a typical room’s floor/ceiling null is in the critical mid-bass centered at 80 Hz, it can wind up being very broadband, making for a very weak sounding ‘bass’ even if there’s a strong true bass [<~80 Hz].
You’re welcome! Glad you’re willing to do a bit of ‘due diligence’ rather than just the ‘palm out’ attitude that’s becoming all too prevalent in today’s society.
GM
Greets!
Well, in his sims, his comparison overlay shows the MLTL has an audible amount of bass extension over the BR due primarily to being larger, though its HF roll off isn't as smooth due to its pipe harmonics, which with careful damping can be reduced to inaudibility, though many folks like them since they make it sound 'livelier'; and not shown is the MLTL's better transient response, the main reason for using them IMO, experience.
GM
It’s usually a personal preference ‘thing’, i.e. the best overall is still acoustic fiberglass [FG] insulation AFAIK, but many folks have a health issue with it, so polyfil is/was the main preference, though in recent years shredded cotton [jeans] or similar has become popular.
Bottom line, there’s all manner of materials to choose from: open cell foam, jute, carpet, polyfil, FG, bubble wrap, sponge, etc., with each requiring different stuffing densities, so your call. Personally, I’m ‘old school’, so lining the top, one side and back with 1” acoustic FG [O-C 703 ductboard] is my default damping, then adding it to the other wall and/or doubling up the top if more is needed.
GM
Mmmmhhh having some doubts about my cabinet right now (BR versus MLTL). But I have to stick with it for now because the wooden panels are already cut. I am thinking of building a similar cabinet with a pair of Philips AD12200W. I have them playing in a 85L BR right now....that is quite nice. But before I start another project I will stick to the first plan...
R.
R.
Nothing wrong with a well damped BR, just that if you have the room and need a stand, why not just make a tall cab to 'kill two birds with one stone' and get a bit more bass, good-excellent transient response with less stuffing?
GM
Hi, you describe my doubt exactly. But looking at the wooden panels lying here on the floor it would be a waste of money not to use them.. So I will go ahead with the build. That way I can also cross building a big monitor from my list.
(In the meanwhile I will design a bigger cab....).
R.
Hi,
I have put together the cabinets. They turned out not as square as I hoped.I think its because I was a bit rushed, but It can be fixed (I think). I am still the finish because the budget does not allow veneer so I have to come with something different. I will post some pics soon.
beto1 I can't help you with the M15's sorry.
R.
I have put together the cabinets. They turned out not as square as I hoped.I think its because I was a bit rushed, but It can be fixed (I think). I am still the finish because the budget does not allow veneer so I have to come with something different. I will post some pics soon.
beto1 I can't help you with the M15's sorry.
R.
Hi GM,
As I said the cabinet turned out not quite square and flat, this is very frustrating and is difficult to get right.
Because of this issue I am looking at thin sheets of wood (3 to 5mm), this can also help to make i more square and flat. But these sheets are not cheap and need finishing.
Si I am currently looking at high quality foil in wood design, drawback is that the finish needs to be spot on. Maybe a combination will be the solution..
Next time I will use lamello's or dowels... for now it is sanding, glueing and some more sanding... the good thing is it keeps me busy...and don't need to go to the gym.
R.
As I said the cabinet turned out not quite square and flat, this is very frustrating and is difficult to get right.
Because of this issue I am looking at thin sheets of wood (3 to 5mm), this can also help to make i more square and flat. But these sheets are not cheap and need finishing.
Si I am currently looking at high quality foil in wood design, drawback is that the finish needs to be spot on. Maybe a combination will be the solution..
Next time I will use lamello's or dowels... for now it is sanding, glueing and some more sanding... the good thing is it keeps me busy...and don't need to go to the gym.
R.
Greets!
Understood and have either built or been 'party' to all manner of non square 'squares', so my point was that we found wallpaper in general and [marble] free form patterns combined with its somewhat matte finish 'tricked' the eye well enough for all but the builder and even then, once in service they just become part of the room's 'landscape' and pretty quickly too if they blend to it.
Kind of an interesting phenomena, how our mind chooses to see what we think we want/expect. In the bad old days of manual ink screening of t-shirts, etc., multi-colors in particular were problematic in getting full coverage with each without overlap even on a flat, rigid surface, so with a 'stretch' material all we could do was average out each overlay.
This resulted in color overlaps as well as blank spots around/in the 'picture' that to the screener looked pretty sloppy, yet wasn't noticed by anyone else except someone looking for them.
In short, adjusting the bottom to average out any glaring leaning/top out of parallel with the floor, etc., but not actually plumb and square normally suffices.
GM
Understood and have either built or been 'party' to all manner of non square 'squares', so my point was that we found wallpaper in general and [marble] free form patterns combined with its somewhat matte finish 'tricked' the eye well enough for all but the builder and even then, once in service they just become part of the room's 'landscape' and pretty quickly too if they blend to it.
Kind of an interesting phenomena, how our mind chooses to see what we think we want/expect. In the bad old days of manual ink screening of t-shirts, etc., multi-colors in particular were problematic in getting full coverage with each without overlap even on a flat, rigid surface, so with a 'stretch' material all we could do was average out each overlay.
This resulted in color overlaps as well as blank spots around/in the 'picture' that to the screener looked pretty sloppy, yet wasn't noticed by anyone else except someone looking for them.
In short, adjusting the bottom to average out any glaring leaning/top out of parallel with the floor, etc., but not actually plumb and square normally suffices.
GM
First, sorry for the very bad photo..
But Today I finally could press "Play" on my No knowledge an No budget build and listen....
So we have a very simple box, a 15.5 cm long +/-11 cm diameter port and a minimum of damping material (felt) No filter.
OH! My etc.... First I used an AD12200W Subwoofer to assist the AD12202 in the open baffle... well I don't need that anymore... It sound wonderfully! Yes there is another "Live" feelling compared to the open baffle and yes there is just a small "sweetspot" and there is some efficiency lost...but who cares!! it sounds great!!
I think (am sure) it could be tweaked to get even better, but for now the Bach Cello suites and the Live recording of Trentemoller etc... sound great...
R
But Today I finally could press "Play" on my No knowledge an No budget build and listen....
So we have a very simple box, a 15.5 cm long +/-11 cm diameter port and a minimum of damping material (felt) No filter.
OH! My etc.... First I used an AD12200W Subwoofer to assist the AD12202 in the open baffle... well I don't need that anymore... It sound wonderfully! Yes there is another "Live" feelling compared to the open baffle and yes there is just a small "sweetspot" and there is some efficiency lost...but who cares!! it sounds great!!
I think (am sure) it could be tweaked to get even better, but for now the Bach Cello suites and the Live recording of Trentemoller etc... sound great...
R
Attachments
Problems.....
It has been a while but I thought to let you all know where the project is right now...
To be honest there are problems...and I need help..
I wrote (a bit over enthusiastic) about the good listening results. And yes there where some things missing but I could only get better...well it didn't.
One off my precious AD12202M died...please don't ask why. Also don't ask why my pair off Philips AD12200W died in the same week... In the meanwhile I tidied up the cabinets and place them on beautiful Oak feet. After hours of sanding I am very much in love with the looks.
I quickly found a new pair once they sat in the cabinet it was very clear that they didn't sound the same as my old drivers. The cabinets now sit much lower on there stands as in the first listening test.
Conclusion it sounds bad....very bad to bright, missing bits and peaces etc.
Now I remember my now doubts mentioned in this thread but I also recall that the cabinets are big enough to try other drivers and other pieces of advice.
I am hoping on your advice again. So what to do? I myself have come up with a few options:
1. go for another 12" full range speaker (with or without helping tweeter)
Eminence Beta 12LTA+tweeter?
2. go for a 12" woofer and add a big tweeter
Eminence Beta 12A +Selenium D220Ti?
3. go for a 12" woofer and add midrange and tweeter
Philips AD12200W + PhilipsAD5060SQ8 + Philips AD0160
The last option is near to my weakness for Philips drivers but I am open for options...
R.
It has been a while but I thought to let you all know where the project is right now...
To be honest there are problems...and I need help..
I wrote (a bit over enthusiastic) about the good listening results. And yes there where some things missing but I could only get better...well it didn't.
One off my precious AD12202M died...please don't ask why. Also don't ask why my pair off Philips AD12200W died in the same week... In the meanwhile I tidied up the cabinets and place them on beautiful Oak feet. After hours of sanding I am very much in love with the looks.
I quickly found a new pair once they sat in the cabinet it was very clear that they didn't sound the same as my old drivers. The cabinets now sit much lower on there stands as in the first listening test.
Conclusion it sounds bad....very bad to bright, missing bits and peaces etc.
Now I remember my now doubts mentioned in this thread but I also recall that the cabinets are big enough to try other drivers and other pieces of advice.
I am hoping on your advice again. So what to do? I myself have come up with a few options:
1. go for another 12" full range speaker (with or without helping tweeter)
Eminence Beta 12LTA+tweeter?
2. go for a 12" woofer and add a big tweeter
Eminence Beta 12A +Selenium D220Ti?
3. go for a 12" woofer and add midrange and tweeter
Philips AD12200W + PhilipsAD5060SQ8 + Philips AD0160
The last option is near to my weakness for Philips drivers but I am open for options...
R.