First Build - Qts, Sound Characters, and TQWT

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jwicaksana

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Joined 2015
moxsphotography.com
#1
Update on post #47 🙂

Hello everyone,

My first post here, my name is Jonathan, from Jakarta, Indonesia 🙂
A little background, I've always loved music, have a simple car audio system, and some ear/headphones. I've always thought that home audio is expensive and big and takes a lot of power (- electric bill 😱 ) That changed when a friend told me about high efficiency full range drivers. That was a turning point, really. I'm losing sleep over countless reading on the internet on this subject. 😀

For my first project, he suggested that I build a TQWT, saying that TL is good to boost the bass on smaller drivers, but TQWT is somewhat simpler to design. Now the calculator over at mh-audio.nl suggested a driver with Qts of 0.2-0.7 with the ideal being 0.4-0.5. I listen to jazz, pop, and rock music, and particularly enjoy female vocals. I want to have a clear and open sound, leaning towards clear than warm.

I've done some research on Parts Express, looking for 3" full range drivers within said Qts range, and have found some Tang Bands (926SD, 315E, 593SF, 881SJF) and Fountek FE85.

Kindly advise:
- Is TQWT a good first project for the sound I'm looking to get?
- What does Qts do in this application?
- Is there a particular forum darling within the choices I've mentioned, or you have other suggestions in that price range?

TIA for your kind response. I've read many threads, including suggested threads when I compose this, but maybe I've missed a thing or two.

Regards,

Jonathan
 
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#2
If you are new to quarter wave type TL and single full range drivers - try an easy to make proven design to get you going. You will learn a lot and it will sound good as a reward. Look at the Tabaq thread and try to find a locally available 3in to 4in driver with Qts in the 0.5 to 0.7 range.

http://www.diyaudio.com/forums/full-range/88787-tabaq-tl-tang-band.html

Another choice is the mini Karlsonator. If you can get a Vifa TC9FD, or Faital Pro 3FE25, or any of the above Tang Bands can work with some adjustments to box width and scale. This speaker has a lot of bass gain and is one of the few that needs no baffle step compensation. Meaning that overall sensitivity down to bass corner is same as rated sensitivity - not -4dB to -5dB less.

A 91dB 3FE25 in a 0.4x K'nator will have 91dB down to 80Hz and f3 of about 70Hz.

http://www.diyaudio.com/forums/full-range/239338-mini-karlsonator-0-53x-dual-tc9fds.html
Also, look in index of post 1 of Foam Core speaker thread for ideas.

http://www.diyaudio.com/forums/full-range/223313-foam-core-board-speaker-enclosures.html

Qts refers to one of the main electro mechanical parameters that describe a driver will behave in a particular enclosure. It is related to the power of the motor and stiffness of the suspension. Low Qts is powerful motor and high Qts is weaker motor. You want a moderate Qts for a MLTL or many TQWT speakers.
 
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#3
@xrk971 Thank you for the detailed response!
I will read the links you provided, and I happened to have stopped by the foam core board enclosure thread, will do more detailed reading.

For starters, the TQWT schematics and formula from mh-audio.nl calculator seems reasonable for me to attempt. Thanks for explaining the Qts, I hope the ones I pick in the 0.4-0.5 range would do fine for starters.

P.S. A few hours ago this friend who introduced me to this project, gave me a small PAM based kit, and I hooked everything up, and it works nicely. I guess I can now officially say I've started my journey as a DIY-er 🙂
 
#6
mikejennens said:
Good suggestions thus far. Another might be to try a MarkAudio CHP70 in a Pensil.

http://frugal-phile.com/boxlib/pensils/PensilP70s3-map.pdf

I've been very impressed with MarkAudio drivers, as have been most fans of full range drivers. Great value and a relatively simple build.
Mike
Click to expand...
Hi Mike, thanks for turning my head to MarkAudio and Pensil design. That looks simple and nice indeed. Thanks, really appreciate it.

planet10 said:
Jonathan,

Do note that that calculator is not worth the pixels is is made of.

dave
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Thanks Dave, I've checked your frugal-phile website and now in the process of downloading some drawings there.
 
#9
TL and TQWT are somewhat different in character.

All other things being equal - though they never are, a TL will sound more neutral, uncolored and hifi. A TQWT will have a tendency to sound fun and punchy and perhaps a bit more colored.

For little 3" drivers IME and IMO you are better off with higher Qts that .4 to .5. I'd say go at least .7 for either a TL or TQWT. With an ML-TL you can go lower.
 
#10
jwicaksana said:
Also, if I were to build a Pensil enclosure with one of the 3" Tang Band, how do I adjust the dimensions of the enclosure? Thanks.
Click to expand...

Pensils are designed for Mark Audio speakers. If you are planning on using a different driver, you'll have to take the basic design parameters and model a new line (Leonard software).

As has been mentioned, if you like the Pensil concept, and want to use a TB, TABAQ is a good start. For something less like a monkey coffin, and even better performance in our experience, check out Frugel-Horn Lite.

dave
 
#11
Greg B said:
TL and TQWT are somewhat different in character.
Click to expand...

Not always. Scott designed an ML-TL for the Peerless 830870 which we use with the uFonkenSET.

uFonkenSET-matched-woofT.jpg


With the next evolutionary development i needed a taller line as i wanted to use 4 woofers and have them sandwich the midTweeter so i had Scott turn the ML-TL into an ML-V. Except for quantity bass is very similar.

Here with no drivers and freshly clad in very thick yew veneer (which showed up some issues with bracing that we still need to fix). They have since had some rebates & the sharp edges softened.

Facets-noDrivers-simple.jpg


dave
 
#12
theaspin said:
For 3" TB you should build a TABAQ 🙂 It's much smaller but it should have decent amount of bass. Or you can try 5" TB with TABAQ large.
Click to expand...
Thanks, it is definitely most interesting for me, I've read that thread and will keep that for future projects.
Greg B said:
TL and TQWT are somewhat different in character.

All other things being equal - though they never are, a TL will sound more neutral, uncolored and hifi. A TQWT will have a tendency to sound fun and punchy and perhaps a bit more colored.

For little 3" drivers IME and IMO you are better off with higher Qts that .4 to .5. I'd say go at least .7 for either a TL or TQWT. With an ML-TL you can go lower.
Click to expand...
Hi Greg, thank you. From my reading, is it correct to understand that there are three TL designs, one with opening smaller than beginning of line (conventional taper), one with constant area (straight), and one with opening larger than beginning of line (TQWT)?
Bob Brines mentioned that straight and conventional taper would give smoother frequency response at the cost of slightly lower output volume?
Please kindly advise, or otherwise point me to the right direction. 🙂

planet10 said:
Pensils are designed for Mark Audio speakers. If you are planning on using a different driver, you'll have to take the basic design parameters and model a new line (Leonard software).

As has been mentioned, if you like the Pensil concept, and want to use a TB, TABAQ is a good start. For something less like a monkey coffin, and even better performance in our experience, check out Frugel-Horn Lite.

dave
Click to expand...
Dave, the regional distributor of MA has gotten in touch with me, I might buy a pair of CHR-70.3 for next project. Thanks so much.
 
#13
Now the reason why I said 'next project' is because I have found myself a locally available driver, the awesome thing about this is they provide the measurement for each driver they produce. Mind you, where I live, NO driver below USD30 equivalent that provides chart or anything like that, so I was pretty happy with this.

Diameter 5"
Impedance 8 Ohm
Sensitivity 1M/1W 85 dB
Voice coil diameter 0.56 inch / 1.42 cm
Fs 125 Hz
Qms 7.13
Qes 1.93
Qts 1.52
BL Factor 2.2N/A
Mms 2.1 gram
Vas 2 liter
Sd 43 cm2

Would somebody elaborate what you can conclude from the above specs? And what kind of enclosure is best for this driver? I'm breaking this driver in, by mounting it on a cardboard box, it sounds nice even that way. Last night I 'installed' it and this morning it's sounding better already.

Thanks fellas, really appreciate you being so kind to share.
 
#14
With this high a Qts, OB or its proper TL straight tapered equivalent is best overall, so tune to 125/1.52 = ~82 Hz using Hornresp or similar software, preferably offsetting the driver at some odd pipe harmonic from the closed end to keep stuffing density reasonable and as you've already learned from cardboard mounting, making it from a lossy material such as foam core will further reduce the stuffing density required.

GM
 
#15
GM said:
With this high a Qts, OB or its proper TL straight tapered equivalent is best overall, so tune to 125/1.52 = ~82 Hz using Hornresp or similar software, preferably offsetting the driver at some odd pipe harmonic from the closed end to keep stuffing density reasonable and as you've already learned from cardboard mounting, making it from a lossy material such as foam core will further reduce the stuffing density required.

GM
Click to expand...
Hi GM,
So use Fs/Qts to get tuning frequency? Is this the general rule for TL box tuning?
Is there any reliable calculating software online? I won't have access to Windows OS at nights and on weekends, whereas inspirations normally came at said times. 😀😀
 
#19
jwicaksana said:
Hi GM,
So use Fs/Qts to get tuning frequency? Is this the general rule for TL box tuning?
Is there any reliable calculating software online? I won't have access to Windows OS at nights and on weekends, whereas inspirations normally came at said times. 😀😀
Click to expand...

I'm not GM but: yes & no. It will give you (damped appropriately) a maximally-flat impedance transmission line, which will get the best from this high Q driver. Other drivers have different requirements -you ideally select the driver (and box load) based upon what you want. If you're stuck with xyz unit for whatever reason, you're basically restricted to doing whatever will get the most from it.
 
#20
Scottmoose said:
I'm not GM but: yes & no. It will give you (damped appropriately) a maximally-flat impedance transmission line, which will get the best from this high Q driver. Other drivers have different requirements -you ideally select the driver (and box load) based upon what you want. If you're stuck with xyz unit for whatever reason, you're basically restricted to doing whatever will get the most from it.
Click to expand...

Hi Scott, thanks for stopping by. You're right, I'm restricted to doing something to get the most from this driver. After much consideration, I'll build a proper enclosure with a proper driver, so far I like the Pluvia on a Pensil, or the Tang Band on a TABAQ. For this one, I might want to keep it simple and do an open baffle instead. Does that sound like a sound idea? (pun intended 😉 ) Also, any pointer on where to turn for baffle size calculator?

I know I sound like a clueless and I am, but I'm genuinely interested in getting a proper sounding system, and am keen to learn. Thanks everybody for your support in this forum! 🙂
 
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