I bought a pair of these a while ago and want to make a bedroom MLTL mini-towers for them. Intended use case is 2 channel music at bedroom levels.
This is the driver
Dynavox LY302F 3-1/2" Full-Range Driver
This is my first time using hornresp, so I appreciate any feedback
Thanks!
This is the driver
Dynavox LY302F 3-1/2" Full-Range Driver
This is my first time using hornresp, so I appreciate any feedback
Thanks!
Please use HR's Export feature to attach it, so we can download/install. As for what we can see, I'd just move the driver down a bit to close up the phase mismatch at ~190 Hz.
A second attempt
Cross-sections seemed tiny and I'm skeptical that this can get that low, so I made some changes.
Smoothing out the response resulted in an oddball shape for the last segment.
Cross-sections seemed tiny and I'm skeptical that this can get that low, so I made some changes.
Smoothing out the response resulted in an oddball shape for the last segment.
I love this driver. Bought 8 of them a year ago and keep using it in builds. I've never managed to get it to reproduce below 100hz at volume successfully without quickly running into excursion problems. Its has a low fs but relatively small xmax.
Your plan reminds me of this, so it can be done;6moons audio reviews: John Blue Audio Art JB3F
Your plan reminds me of this, so it can be done;6moons audio reviews: John Blue Audio Art JB3F
Check "Displacement" in Hornresp Horn wizard against xmax. My guess is it will go wild below 60hz. A similar plan I had used a bipole arrangement using a TC9FD (or similar) at the rear, which brings the displacement down to usable levels whilst keeping the small cross-section. This could be slightly lowpassed and used as a mini helper woofer.
Do you have your builds online anywhere?
Interesting that the commercial offering linked has an F3 of 85hz. Perhaps a more reasonable goal? The driver he's using is definitely the Dynavox.
No, mine have both been crossed over to a larger woofer around 300hz 1st order where it sings. I had one in a small 2ltr ported box on its own and although it sounded nice and full, breakup started too soon for me. It only has 1.5mm xmax. But I have been thinking about john blue clone, similar to the OP. "When coupled to the TQWT cabinet, bass response extends to 42Hz"!
I would think the low-end peaking suggests Vb is too large and Fb too low. The Vas of this driver is quite small after all.
It's not like I never committed flawed and oddball designs to wood myself, but I'm assuming you're going for a more orthodox design paradigm.
It's not like I never committed flawed and oddball designs to wood myself, but I'm assuming you're going for a more orthodox design paradigm.
You're welcome!
Thanks! Though I meant attaching them to your post using the Toolbar's little 'paperclip' symbol button.
More tweaking yields the following. I'm really just button smashing here.
Displacement looks reasonable now as I'll only be playing at bedroom levels.
Any suggestions as to how to get the ripple at 300hz out? Is this something that would be audible if I build the thing?
Displacement looks reasonable now as I'll only be playing at bedroom levels.
Any suggestions as to how to get the ripple at 300hz out? Is this something that would be audible if I build the thing?
OK, time for a bit of a [BR], [ML]TL basic design tutorial to at least get you pointed in the right direction, if not a 'close enough' finished box alignment in the hope that you'll be able to critique yours and improve on them:
As for how far below Fs is practical depends on a number of things, though with a basic BR out away from walls/corners, a 1/2 octave [~0.707] below Fs is the rule-of-thumb [ROT] based on excursion increasing at 4x/octave.
In short, > ~0.403 Qts' is where Fb < Fs and its effective upper mass corner is where basic T/S theory peters out, so, any change in a basic sealed/vented box alignment's sim above this point will be due to the driver's inductance [Le].
upper mass corner: Fhm = 2*Fs/Qts'
[Qts']: [Qts] + any added series resistance [Rs]: Calculate new Qts with Series Resistor
[Rs] = 0.5 ohm minimum for wiring, so may be higher if a super small gauge is used as a series resistor plus any added resistance from an XO/whatever.
There are many T/S theory box alignment routines, though this one for max flat reflex alignments is my preference:
Margolis-Small's HP 67/97 & 41C calculator program: AES E-Library » Personal Calculator Programs for Approximate Vented-Box and Closed-Box Loudspeaker System Design
net volume [Vb] [L] = 20*Vas*Qts'^3.3
box tuning [Fb] [Hz] = 0.42*Fs*Qts'^-0.96
To the 1st approximation then is to calculate the box net volume [Vb], tuning [Fb] for ANY reflex BR = vented] alignment with these basic understandings:
While the 'sweet spot' [mean] is a ~0.4412 Qts', a 'close enough' simple guideline for [BR], mass loaded [ML = vented] TLs is:
~0.403, Vb = Vas, Fb = Fs [MLTL]
< ~0.403, Vb = < Vas, Fb = > Fs [inverse tapered MLTQWT]
> ~0.403, Vb = > Vas, Fb = < Fs [expanding taper MLTQWT/MLhorn]
Where Qts' breakpoints are IME since I've never seen any professional docs on the subject per se other than the Efficiency BW Product [EBP]: Red Spade Audio: Efficiency Bandwidth Product (EBP)
< ~ 0.312 = low
~ 0.312 ~ 0.62 = medium
> ~ 0.62 = high
Heavy damping limitations:
While the three different tapered TLs and their vented alignment variants [mass loaded/MLTL, MLTQWT, MLhorn] can be used with any driver, there's a 'best overall' range for each IME, so FWIW:
Inverse tapered TQWT for when the vent's dimensions are long/large for the box size [Qts' < ~0.312] same as for passive radiators [PR]
Expanding tapered TQWT [horn] for when specs dictate a tuning below Fs for flattest response [Qts' > ~0.403]
Constant [straight] tapered TL for when specs dictate an alignment in between the above extremes [~ 0.312 - 0.403 Qts']
The vent/horn terminus opening causes a downward shift, hence the distances are further down than a closed box's 1/5, 1/3rd, etc., but both the driver and vent should be at a vented pipe's odd harmonics. You can figure it out using Hornresp's
'path' slider in 'chamber' or just use these as proven audibly 'close enough':
Driver offset [Zd] = [L]x ~ 0 [top], 0.217, 0.349, 0.424, 0.561
Of course the first one doesn't apply to any ~zero area [CSA] terminated pipe/horns and if your desired ear seated/whatever driver height doesn't line up close enough to your design, suggest you change the alignment tuning [pipe's length] by adjusting Fs to get it to line up with one of these offsets.
Vent offset only, depending on box HxWxD ratio: vent offset [Zv] = [L]x ~0.651, 0.714, 0.848, 0 [bottom]
Seems like there's more tidbits I've posted over the decades, but ran out of time to search, though should be enough to see the 'error of your ways' 😉, do another sim for us to critique before I post mine............
"Any suggestions as to how to get the ripple at 300hz out?" adding some light filling might help.
Does displacement below f3 matter in Hornresp models? I've oft wondered this.
According to the John Blue review, there's nothing in the box. Its just a straight TL to the floor, which acts as a vent/mouth I assume. I'd like to hear this and it looks a simple build.
Does displacement below f3 matter in Hornresp models? I've oft wondered this.
According to the John Blue review, there's nothing in the box. Its just a straight TL to the floor, which acts as a vent/mouth I assume. I'd like to hear this and it looks a simple build.
Yeah, the TL I did is only ~87.6 dB/~1 W/~54 Hz/2pi assuming a bit of overdrive to a 2 mm excursion limit, so OK for computer, Muzak apps.
I appreciate that you took the time and care to put this post together. Let me take a few days to digest and get back to you.
I work with startup founders on a daily basis. Single biggest factor I've seen in terms of predicting positive outcomes is coachability.
Kinda nice to be on the receiving end.