Hi all,
I've been lurking for a while but now I have a project to get my teeth into!
I'm looking at building one enclosure with single driver to sit on the kitchen mantelpiece to be driven by a single channel amp (or 1 channel of a stereo amp, or bridged stereo). This location brings with it some parameters for size:
The shelf is about chest height when standing and is in the middle of the wall.
It will be used for fairly low volume background music, though I'm partial to quality bass 😀
I've been looking at single full range drivers and have been interested in trying some sort of transmission line, unless that's totally crazy and a sealed/ported enclosure would be more suitable. TL's have appealed since reading V. Capel's enclosure design book from the 90's but I understand that some of the theory and maths used in his TL design has since been disproven/superceded.
I've been playing around with the enclosure calculators on DB Dynamix, specifically the single-fold off-axis (non-tapered) TL one. I'm not sure what maths and theory these sheets are based off, however, so not sure if I should trust them. There is no info on positioning the driver in the front baffle. I'll post a screen cap of my current calculations below later.
Driver selection so far is the Dayton ND91-8 based solely on size (due to internal height of cab) and resonant frequency (as low as possible? 70.7Hz on the 3 1/2" ND91-8!)
My questions at this stage are:
I've been lurking for a while but now I have a project to get my teeth into!
I'm looking at building one enclosure with single driver to sit on the kitchen mantelpiece to be driven by a single channel amp (or 1 channel of a stereo amp, or bridged stereo). This location brings with it some parameters for size:
- Depth (front-to-back) - Maximum 16cm (6.2")
- Height - as low as possible to minimise visual impact, but probably 5" to 6"
- Width - Maximum 20" to 24" give or take
The shelf is about chest height when standing and is in the middle of the wall.
It will be used for fairly low volume background music, though I'm partial to quality bass 😀
I've been looking at single full range drivers and have been interested in trying some sort of transmission line, unless that's totally crazy and a sealed/ported enclosure would be more suitable. TL's have appealed since reading V. Capel's enclosure design book from the 90's but I understand that some of the theory and maths used in his TL design has since been disproven/superceded.
I've been playing around with the enclosure calculators on DB Dynamix, specifically the single-fold off-axis (non-tapered) TL one. I'm not sure what maths and theory these sheets are based off, however, so not sure if I should trust them. There is no info on positioning the driver in the front baffle. I'll post a screen cap of my current calculations below later.
Driver selection so far is the Dayton ND91-8 based solely on size (due to internal height of cab) and resonant frequency (as low as possible? 70.7Hz on the 3 1/2" ND91-8!)
My questions at this stage are:
- What will be the resultant heard differences between a side-exit and front-exit TL?
- Is 1/2" wood thick enough for this enclosure considering SPL?
- Any suggestions for alternate drivers? Must be currently available.
- If using a T-amp or other chip amp, is a 4-ohm or 8-ohm driver best?
- Am I barking up the wrong tree pursuing TL design for this size enclosure?
For 70Hz TL length must be around 48". It can be folded, but it might get too shallow. I would suggest building a ported box instead.
You can try modelling both with this software:
Download | Leonard Audio
You can try modelling both with this software:
Download | Leonard Audio
1) Very little to none.
2) yes
3) It depends on your taste and lots of things. Search through some driver shootouts at this sight maybe.
4) ask someone else, I don't know.
5) No, little TL cabinets are great fun and IMO often have more realistic sounding bass than BR.
Some general comments:
A shallow cabinet 20-24" wide typically brings the baffle step down to where room gain starts to kick in, and as a result you won't need any sort of baffle loss compensation. I've always thought shallow and wide is was a great approach for a FR driver and i'm surprised more people don't use it.
Yes, all of those older TL design approaches have been superceded. Take a look at MJK's quarter-wave.com. Leonard's TL software as well as hornresp are good modeling tools to check out.
I prefer higher Qts drivers when using a small FR for a true TL. The .7 to 1.0 range works well for me. That dayton would be more suited to a ML-TL IMO.
Search for the Woden Baby Labs thread. There is a desktop transmission line in that plan set for the Aura NS3, which could also be used for the Dayton ND91. Bass response was reported to be excellent. While too deep for your purposes, perhaps the design can be modified to suit your restrictions.
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Second the Baby Labs… these are likely as small as you are going to get… a TL in general is much larger than an optimal BR or sealed box. And since not many drivers in the size range are designed for sealed boxes so the smallest box you are likely to get is a BR.
The width gives you the volume needed to mutate a reflex into your space.
uFonken is one of our most successful designs.
http://p10hifi.net/tlinespeakers/FAL/box-plans/microFonken-0v9-map.pdf
There is also a slightly larger and a slighly smaller (the last not built yet).
dave
The width gives you the volume needed to mutate a reflex into your space.
uFonken is one of our most successful designs.
http://p10hifi.net/tlinespeakers/FAL/box-plans/microFonken-0v9-map.pdf
There is also a slightly larger and a slighly smaller (the last not built yet).
dave
According to WinISD, the ND91-8 can play to 60hz or so in a 2.5L box. You could have 2 of them and more in your space. 🙂
1. Hard to say, it's your room. Typically, side/rear ports would need something to bounce off. And front ports splurge more of the unwanted harmonics and rear of the cone soundwaves straight at you.
2. Yup, should be.
3. Mark Audio Alpair 6M? If you need bass, consider a 2 way with ND105 plus tweeter.
4. Depends on amp and speaker specs. Typically 8 ohm is more benign.
5. Nope - but hard to find one ready to build. An MLTL would offer more in terms managing harmonics. Essentially, with the dimensions quoted, it'll be a TL or MLTL anyway, unless you build two speakers and sit them on either end.
It may need to be 48 inches for a conventional TL, but an MLTL can be much shorter, for the same tuning frequency and will have a much flatter frequency response than a conventional TL anyway. I would consider an MLTL something like the TABAQ for 3 inch drivers:
TABAQ Tang Band Quarter Wave
That design (turned on its side) meets your cross sectional restrictions but is longer than you wanted (it's about 32 in long). However, it could be shortened if the port is made longer or the port opening made smaller.
I second the recommendation by theaspin to download the Leonard Audio TL software. It's is virtually the same as the MLK program but easier to get access to, and it is very easy to learn to use. With it you will be able to see if you can get away with shortening the cabinet by tweaking the port size.
Eric
+1 for this app, though for free standing I prefer > 1.0 and tune to Fs/[effective] Qts to get some built-in BSC.
GM
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