Collaborative Tapped horn project

[freddi]

hey Don - just felt like I was cluttering up things over at AA. Sounds like TH cone movement is under good contro although I'm not familiar with that cut of much of Fleck - - have your run DAFO's drop? - that seemed to center around 23Hz with a bunch of overtones and some sense of room ambiance

do you think the shock wave effect is partly psychoacoustic? Karlsons, although not going deep by sub standards can exhibit a quick wave. I'm using Klipschorn and those sound horrible & tubby on harpsichord recordings -ugh (K12 did more exciting bowed bass with Gary Karr's Koussevitzsky cd) If I can't get drum, cello and bowed bass semi-acceptable then am doomed from getgo.

hope your threshold offset comes back fast

lets get a coupler and tiny HF pipe going - not sure if would cover your room - how large?

Freddy

[GM]

Originally posted by rick57


If you were responding to me, no I don’t think reflex alignments are fundamentally flawed, just wondered if their may be better way (“good> better > best”) to optimise for fast transients & fast decay, than the normal use of sims & tuning

Anything you could add on OBs?

Thanks Again

Greets!

You're welcome!

No, that whole response was to one of Freddy's. Your 70 L/40 Hz Fb alignment actually has a very low GD, just no mid-bass 'slam'.

WRT 'fast' reflex alignments, the roll off slope and Fb will determine its GD and can be tailored to have the same GD as a Qtc = 0.5 sealed over the BW above Fb and if tuned low enough to decay away to ~15 ms/35 Hz, then due to our lack of hearing acuity down low the reflex will sound as 'tight' as the critically damped sealed alignment. If tuned higher, then a HP filter is required to damp the increasing GD below Fb.

?? You have to use something to optimize a reflex alignment. I mean if there's a reflex alignment that zeros in on the optimum GD alignment, I'm either not aware of it or it plum evades me at the moment as all I can envision are TLs and horns.

Linkwitz ~literally 'wrote the book' on OBs, filling in whatever Olson missed or glossed over, so no point in me re-hashing it.

GM

[GM]

Originally posted by rick57

Wouldn't that also apply to passive XOs?

Do half horns have a similar drawback to Karlsons - they can't be ~accurately simmed; how close is it to a back loaded conical?

TI also have some JBL 2202's...........would they work ok in a half horn?

> and while their impulse response are more resonant than a typical alignment
You are saying for impulse response, that the 'pecking order' is sealed eg Q = 0.7, typical vented, then half horns; but that many people don't hear a (significant) difference?

With sealed & vented, I thought the steeper the rolloff, the less ideal (rapid) the impulse response. Amp aside, are you suggesting that mounting a driver in an OB somehow lowers Qts, and improves impulse response?

Greets!

You're welcome!

It applies to passives also, but you'll need very 'deep pockets' to afford a 80 Hz 4th order passive.

They can be ~accurately simmed by any program that can do BLHs or DBRs. Most BLHs are basically big vent reflexes (BVR), so a half or 'hit' horn is just a truncated variant, ergo can have whatever expansion you want.

Not really, you want Fh to be beginning of the 'bump' BW, otherwise you get a deep notch between Fh and the 'bump' BW.

Pecking order WRT technically 'perfect' to acceptable transient response AFAIK is 'perfect' BLH, 0.5 Qtc 1/2 WL pipe, 0.5 Qp TL, 0.5 Qtc sealed, EBS reflex, 0.7 Qtb reflex. What sounds acceptable OTOH is room, frequency, alignment, personal sound perception dependent and why technically horrible systems such as the BIB pipe horn, Karlson, etc., can be very 'live'/'musical'/whatever, sounding to certain folks. As a general rule, we like plenty of harmonic distortion if its the right kind in the right BW, just like preferring 'rich' foods over 'healthy' (bland) ones or TVs tuned 'hot' Vs color balanced for most natural reproduction.

You're missing the point. If I have a driver with a Qts = 1 it will have an under-damped 'hump' in its response with the associated 'ringing', but if I put it on the correct size baffle that rolls it off so there's no 'hump', the system's effective Qt is lower, ergo no longer under-damped, improving its impulse response.

GM

[GM]

Originally posted by freddi
hey guys - regarding mass.......

........I think - like central vent K15 style having a diferent sound than side-gapped.

a K going a couple notes lower than K15 might be fun as an experiment - which woofer type?

what does height of a K's front pipe have to do with its lumped front tuning?

CN is emphactic about raising coupler-height.

If this has some bearing, how should the front chamber be set aspect-wise vs Sd for most efficient use of bulk and least amount of interference dips on the plot? (I almost concur withi CN that transients can sneak past dips)

B&C 15PZB even if went "aperiodic" might not sound tight since it sounds "thick" running 2-way in reflex or with reflex port stuffed.

How does that kluge in Hornresp?

Greets!

Once again, mass per se isn't the problem, it's the higher Qts due to not having a strong enough motor to compete with a lower Qts one.

?? What do you mean by 'side gapped vent' in a K?

At a glance, you'll need a lower Fs driver with the same ~230 Hz Fh that you say works well (Altec 421), so ~28 Hz Fs/0.227 Qts.

The K doesn't have a front 'pipe', none of the chambers have a high enough aspect ratio for TL action to occur in its passband.

'Lumped' front tuning? See my earlier explanation of how a K works. What are you calling a 'coupler'?

Don't know for sure, but it seems to me that baffle angle Vs cutout shape would mostly be a front volume Vs vent tuning thing just like any BP.

Yeah, the B&C is fairly well damped, but has a high Le, so I can see why it might not blend with a horn very well unless XO'd low/steep and its specs indicate tiny front/rear chambers in a K due to its exceptionally low Vas. The stiff suspension is probably the major cause for its 'thick'/'sluggish' sound.

Can't comment WRT the TH, though I'm curious how you 'kluge' it in Hornresp.

GM

[rick57]

Hi GM

> the roll off slope and Fb will determine its GD and can be tailored to have the same GD as a Qtc = 0.5 sealed over the BW above Fb

the indicator of GD being the (inverse of) the steepness of the roll off slope?

> the optimum GD alignment . . all I can envision are TLs and horns.

So TLs and horns have *better GD reflex or even sealed? Can GD be modeled for either of these?

> Linkwitz ~literally 'wrote the book' on OBs, filling in whatever Olson missed . .
I've read his material a few times, but don’t recall any discussion on OB GD/ Qt . .

Cheers

[rick57]

Hi GM

> you'll need very 'deep pockets' to afford a 80 Hz 4th order passive.

mmm, yes

> They can be ~accurately simmed by any program that can do BLHs or DBRs.
What is a DBR?

> As a general rule, we like plenty of harmonic distortion if its the right kind in the right BW, just like preferring 'rich' foods over 'healthy' (bland) ones or TVs tuned 'hot' Vs color balanced for most natural reproduction.
Good analogies

> Pecking order WRT technically 'perfect' to acceptable transient response AFAIK is 'perfect' BLH . . .
I thought a large proportion of a BLHs' bass is out phase, compromising transient response.

> Your 70 L/ 40 Hz Fb alignment actually has a very low GD, just no mid-bass 'slam'.
If GD may not be easy to distinguish (room, frequency, alignment, perception dependent) and I certainly like slam, maybe my criteria would be better weighted towards slam . .

* What is your pecking order for midbass 70 – 350 Hz slam (including I hope an option for something able to be modeled and not as complex to build as a front horn, just yet)?

Cheers

[freddi]

hahaha GM - yeah - BIB, K's & whatnots = "technically horrible brigade" - even if stinks on ice can be a way to pass time (and money) - if that makes sense in a short and unsplendid life (?)

re:K - somehow CN puts significance upon taller aspect offering advantages but what can that really buy within a fixed bulk? - or worded differently, are there better layouts for K aspect-wise than what Mr. K used and if so what improvements might be possible?

what did KenL have back in the 1990's with a 20x20x70 or so tall K with transflex vent? Are tall K's moving away from coupled cavity and more towards t-line territory with less chance of coupled-cavity peaking? - - if so where might the transition occur? (might be difficult to define when the "pipe" leaks)

K-apertures are supposed to be set to leak energy in an even manner....

re:GD - how is that figured for TH? will ARTA calculate properly? how does one confidently kluge TH simulations with Hornresp? - looks like there may be some patterns

which of these two aspect is - uh "better"?

[djn]

Hey Freddi, what would happen if you build the Tapped sub just like Don B did and added the Karlson mouth? Would it be smoother? I really like the Tapped and have save all the plans so when I finally settle into a new place and have the $$, I can build a pair. Cheers.

[djn]

I don't have a whole gob of money right now, but I do have a 12" KLH sub with a plate amp. How can I figure out if the driver for that sub would work in a Tapped sub? I don't have the money for an experiment, but I could swing for a couple sheets of MDF if I know it would work. Is this wishful thinking? Cheers.

[freddi]

k-slot might ruin the tapped horn--? - for experiment that would require a removable front panel

Danley's TH graphs look great!

If you build a 12" TH - as long as driver is accessible then can get right driver later.

on another note, I'm not familiar with Hornresp in BLH mode so not sure how to kluge-simulate TH nor do it with AJ-horn. AJ will go wild & way outta whack in some cases but may be good in certain constraints

here's Don's horn roughly simed as BLH in AJ

how does one kluge sim TH in AH?

BLH
http://img95.imageshack.us/img95/8360/quicksim1uo5.jpg

Power dip ~32Hz Lab 12 in BLH - would power handling dip to ~210 watts @ 32Hz with TH? Don's comments indicated very low cone excursion
http://img95.imageshack.us/img95/145...p32sim1ff5.jpg


56 lliter reflex vs 243 liter BLH
http://img408.imageshack.us/img408/7507/brblhxz1.jpg