Hi FirstOff
As you know TABAQ works with many 3 and 4 inch drivers. And of course, it is possible to get the max out of a driver by making a design for the actual driver.
I have enclosed a sim I made for the Alpair 7, which has some very interesting specs. I have never heard this driver, but would like to.
TL / Quarter Wave in general:
There is no rule about cross section of the line and the surface area of the driver. However, i often start with cross section of 3 times driver area, Sd. Increasing the volume will increase the bass. TABAQ has a rather large volume for a 3" driver and is stuffed rather dense.
The tuning of the line and the driver Qts and Fs is another parameter along with the stuffing.
I prefer a gentle roll off in the bass, to avoid boomy bass. Stuffing controls the bass roll of, the unwanted higher frequencies from the opening and dampen the cone movement below the tuning frequency. Baffle Step Circuit attenuate the treble, which can be too dominating.
There is another parameter: Which size of the the enclosure to you prefer: Often the "max / optimal" design for a driver often turns out to be too large.
Give me a couple of days, and I will do some sims for the 70 driver.
Hi from
Bjørn
As you know TABAQ works with many 3 and 4 inch drivers. And of course, it is possible to get the max out of a driver by making a design for the actual driver.
I have enclosed a sim I made for the Alpair 7, which has some very interesting specs. I have never heard this driver, but would like to.
TL / Quarter Wave in general:
There is no rule about cross section of the line and the surface area of the driver. However, i often start with cross section of 3 times driver area, Sd. Increasing the volume will increase the bass. TABAQ has a rather large volume for a 3" driver and is stuffed rather dense.
The tuning of the line and the driver Qts and Fs is another parameter along with the stuffing.
I prefer a gentle roll off in the bass, to avoid boomy bass. Stuffing controls the bass roll of, the unwanted higher frequencies from the opening and dampen the cone movement below the tuning frequency. Baffle Step Circuit attenuate the treble, which can be too dominating.
There is another parameter: Which size of the the enclosure to you prefer: Often the "max / optimal" design for a driver often turns out to be too large.
Give me a couple of days, and I will do some sims for the 70 driver.
Hi from
Bjørn
The port is mass loading the line. The air in the port has a mass, making resistance to the air flow. This causes the tuning of the line to get lower. If you make a straight line, it will be longer for the same tuning frequency of the line. If you make the line gradually more narrow, the tuning will be lower.
By using a port, you will often see a better overall SPL. My experience is that the port should be 5 inch max.
Take a look at my article
Pearls from Martin J King Quarter Wave Design
On Martin J. King´s site you will find very useful information
Transmission Line Theory
HI
Bjørn
By using a port, you will often see a better overall SPL. My experience is that the port should be 5 inch max.
Take a look at my article
Pearls from Martin J King Quarter Wave Design
On Martin J. King´s site you will find very useful information
Transmission Line Theory
HI
Bjørn
Yeah, I think I got the picture now, after your explanation and a bit more reading.
Essentially the port acts as a bass reflex, complementing the TL, so it becomes closer to the desired tuning without having to have the "ideal" dimension.
So a TL without it would have to have larger internal volume or be tuned higher if one wish to build one of a manageable size.
I was confused about the term "mass loading" the line. A bit slow in making all the connections.
Essentially the port acts as a bass reflex, complementing the TL, so it becomes closer to the desired tuning without having to have the "ideal" dimension.
So a TL without it would have to have larger internal volume or be tuned higher if one wish to build one of a manageable size.
I was confused about the term "mass loading" the line. A bit slow in making all the connections.
Mass loading is an analogy from classical physics with a vibrating cantilever (e.g., tuning fork). If you add mass to the end of the vibrating cantilever it will have a lower natural resonance frequency as if you made it longer. So a MLTL has a lower fb without making it longer, and this is done by constricting the terminus. It really is not a very good term - very confusing. Should be called something like Constricted Terminus TL (CTTL) but whoever coined MLTL, got it to stick. A MLTL and BR really are extremes of the same box but at different length-to-area ratios where the length in the MLTL is long enough to support a 1/4-wave resonance. In fact, stretching a BR out long in aspect ratio and you will get MLTL behavior automatically. It can be done "accidentally" as in here:
http://www.diyaudio.com/forums/full-range/231951-accidental-mltl-technique.html
But to fully optimize requires a model like MJK or can be done in Akabak or other simulation programs.
http://www.diyaudio.com/forums/full-range/231951-accidental-mltl-technique.html
But to fully optimize requires a model like MJK or can be done in Akabak or other simulation programs.
Thanks, wery kind of you.
I listen to the original Tabaq with the vifa 3.5˝ (tg9) and recently rearranged the room. New forniture, etc. Now it is much more impressive. Close to he wall it has much more bass than before in front of a bookshelf. Anyway, I want to make a second pair, and almost ready to buy a Mark Audio speaker but would be happier with a dedicated design to either of the chr70 or the Alpair 7.3 I even consider to buy if I find an exeptional design for it under 90cm heigh.
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I was thinking of raising the whole speakers by extending the bottom. For a cleaner look I'm thinking of either making the bottom port into a hole, or move the port to the back. If I make the port rear-firing, how would that affect the overall sound (not just bass response)? I realize that wall mounting or putting it up against a wall will be unadvisable, but they will be about 30cm away from the wall.
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It´s maybe tradition, but trust me, the slot port isn´t that bad looking, design wise. I like the look when the only round thing in the box is the speaker.
Well that I agree that the slot port is actually very good looking. But when I design it with the speakers raised, the slot makes the speaker looks like it's split into two pieces, like the extended bottom is a piece put on at the last minute and can be taken off. I want the speakers to look "whole". A round port can do that, or making it rear firing.
I think I might go with the slot design but facing the port to the rear. Easier to build that way.
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I think I like it better with the sides painted black, and glossy. I have no experience painting wood, or plywood though. If I could veneer it and get just a tiny bit of the grain showing through the wood, it'll look awesome.
Oh yeah, this one's the design that is raised so that the driver is about 90 cm from the floor.
Out of curiosity, I swapped my living room amp (Pioneer A6-J) with my desktop amp (SMSL AMP-03 TA2020 based T-Amp) and the difference is quite shocking.
The combination of the Tabaq speakers and Pioneer amplifier was a bit bass-shy which I could easily forgive the 3" speakers but with the humble T-amp the W3-871's really come to life. I could not believe the balance between bass, detail and ease to the ears.
After a few days of listening I am quite sure I hit a sweet spot with speaker composition, amp and DAC (Moodlab Concept).
I know the consensus is that a TA2020 based amp is insufficient for low efficient 8 Ohm speakers. If I knew in advance that I would be using this amp, I might have opted for 4 ohm speakers but at the moderate volumes that I listen for 99% of the time, the combination really shines.
The combination of the Tabaq speakers and Pioneer amplifier was a bit bass-shy which I could easily forgive the 3" speakers but with the humble T-amp the W3-871's really come to life. I could not believe the balance between bass, detail and ease to the ears.
After a few days of listening I am quite sure I hit a sweet spot with speaker composition, amp and DAC (Moodlab Concept).
I know the consensus is that a TA2020 based amp is insufficient for low efficient 8 Ohm speakers. If I knew in advance that I would be using this amp, I might have opted for 4 ohm speakers but at the moderate volumes that I listen for 99% of the time, the combination really shines.
Apparently these speakers depend a lot on the receiver or amplifier being used to power them. They don't hide or color much the source limitations. My personal experience was that a CJ MV75 tube amp with KT90's was too much for the speakers, even at lower volume levels, with the TB W3-881SI driver overextending and distortioning, horrible bass. With a Dayton Audio DTA-1 T-Amp (approx. 10 WPC @ 8 Ohms), the sound was nice, very well balanced, clear, detailed, but there was a slight lack of bass. But, with a DIY Class D Amp (70 WPC @ 8 Ohms), these speakers came to life, great sound coming from them, more than adequate bass, still detailed and clear.
If you like the TA2020, try the TPA3116D2. I just wrote a recommendation for it in another thread:
http://www.diyaudio.com/forums/full-range/258283-new-single-drivers-im-blown-away.html#post3973045
http://www.diyaudio.com/forums/full-range/258283-new-single-drivers-im-blown-away.html#post3973045
I have kinda imagined that would happen since the speakers are almost basically "floating" with no boundary around it (in my case with rear firing ports). Maybe I will rethink about having the port at the rear. That way I can place it right up against the wall.
Or......an even funkier idea would be down firing ports.
Wouldn't be much of an extra challenge in terms of woodworking, but I wouldn't know how far off the floor it would have to be. It's an interesting idea, and experiment is easy.
EDIT: Just checked, and maybe for any benefit the speaker wouldn't be as tall as I would like.
Wouldn't be much of an extra challenge in terms of woodworking, but I wouldn't know how far off the floor it would have to be. It's an interesting idea, and experiment is easy.
EDIT: Just checked, and maybe for any benefit the speaker wouldn't be as tall as I would like.
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My current placement happened to be 4.5m from speakers, tabaq placed just against the wall, and the listening position at the opposite wall. The little box just got that bass heavy, I had to move them a little away from the wall. The most I learned with this project , placement matters very much.
Bass is less in the middle of the room of course, and the amound can be fine tuned movind the speakers a little.
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