I'm leaning towards the D-37 plans or the Fostex recommended plans.
My concern with the BIB is blocking my windows(see pic) and WAF. Unless there is a folded alternative around the same size as the D-37? (17" deep, 38" high x 9.5" wide)
So basically it's a toss up:
D-37 or Fostex Horn:
Pros: natural roll off from 100hz down to 40hz, quality of bass such as speed?
Cons: Complex to build, and costlier for more materials.
Bigger is Better (BIB)
Pros: Cheap and easy to build, solid bass extension.
Cons: Low WAF, dip in the 100hz region? (I read this somewhere)
My concern with the BIB is blocking my windows(see pic) and WAF. Unless there is a folded alternative around the same size as the D-37? (17" deep, 38" high x 9.5" wide)
So basically it's a toss up:
D-37 or Fostex Horn:
Pros: natural roll off from 100hz down to 40hz, quality of bass such as speed?
Cons: Complex to build, and costlier for more materials.
Bigger is Better (BIB)
Pros: Cheap and easy to build, solid bass extension.
Cons: Low WAF, dip in the 100hz region? (I read this somewhere)
An externally hosted image should be here but it was not working when we last tested it.
The FE163En-S in the Factory plan and the Nagaoka D37 sim look even closer than kissing cousins🙂 a slight wiggle here or there but nothing of consequence. Stick them in a room of course or more likely in corners and then the bass will come up but the low end response I would hazard a guess would also be about the same between them.
The Victor looks very good. As you said Scott, it is in its designed environment so cannot compare with the other two, nevertheless if it were me I would certainly give the Victor a try and compare with the former two.
For sure if the Victor had a response in the users particular room like the sim it would be difficult to improve upon, just look at the response from ~ 100 cycles down.
The fact that the Victor would be a much easier build is icing on the cake.
Andrew
The Victor looks very good. As you said Scott, it is in its designed environment so cannot compare with the other two, nevertheless if it were me I would certainly give the Victor a try and compare with the former two.
For sure if the Victor had a response in the users particular room like the sim it would be difficult to improve upon, just look at the response from ~ 100 cycles down.
The fact that the Victor would be a much easier build is icing on the cake.
Andrew
D-37 with FE168ez:
D-37 with FE163
Smaller Recommended FE163en-s plans:
D-37 with FE163
An externally hosted image should be here but it was not working when we last tested it.
Smaller Recommended FE163en-s plans:
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Are these measured specs? For sure, they aren't even remotely like the published ones at Madisound.
Note that you didn’t use the ‘combined response’ tool to sum the horn’s output to the driver’s.
GM
Good point -mass looks wrong on a quick eyeball, but I've not used Hornrsp for a bit (life keeps getting in the way). Hope things are as OK as possible your end Greg -got an email half-written in Hotmail that I've been adding to in bits as time permits. 
Sorry about that.
Re a couple of bits (sorry -mashed together a bit, I'm off to bed in a minute) above:
Bass 'speed' in a back horn is to an extent a bit of a misnomer. Bass in itself is slow. Group delay is another matter though. As far as back horns are concerned, the longer the horn is, the lower and / or steeper the acoustic XO will likely need to be to ensure it's held to reasonable levels. The Fostex / Nagaoka boxes aren't all that dissimilar in alignment -not surprising given that they're of broadly similar bulk and path length. The D37 is tuned a bit lower, sacrificing a little gain. Of the two I'd probably be slightly inclined to the that one.
Sorry about that.Re a couple of bits (sorry -mashed together a bit, I'm off to bed in a minute) above:
Bass 'speed' in a back horn is to an extent a bit of a misnomer. Bass in itself is slow. Group delay is another matter though. As far as back horns are concerned, the longer the horn is, the lower and / or steeper the acoustic XO will likely need to be to ensure it's held to reasonable levels. The Fostex / Nagaoka boxes aren't all that dissimilar in alignment -not surprising given that they're of broadly similar bulk and path length. The D37 is tuned a bit lower, sacrificing a little gain. Of the two I'd probably be slightly inclined to the that one.
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The room photo reveals a rather tight space for any enclosure adequate to squeeze all the cream that it's expected this driver can deliver - and having participated in the construction of two different pairs of Nagaoka style boxes for Fostex ESR drivers (166 and 206), I can certain attest to both their lack of gentile WAF, and the fact that they're freaking heavy, even in plywood.
There might well be a better alternative for this driver - watch this space?
There might well be a better alternative for this driver - watch this space?
Sorry, not even close.
The flare rate [m=0.008] is extremely hyperbolic to the point where HR rounds it up to 0.01.
Anyway, the horn’s basics are already spelled out [enclosure design value], though these specs calculate a much more realistic [and close to their measured response using the published specs] F12 = 38.07 Hz Fc as opposed to their claimed 21 Hz Fc, which is actually its calculated F24 pipe tuning [Fp], so no need to figure out anything except ‘Atc’ [width x depth area of Vtc].
The impedance plot is off some though, implying the specs were a bit different in the [probably] pre-production stage and HR doesn’t account for any acoustic damping, hence all the HF ‘ringing’.
Bottom line, a nice driver at a so-so price in a way too small horn.
GM
In which case a tidy little footprint MLTL or such, with 8" or so woofer(s) in small separate enclosure(s) might be a reasonable compromise for this space
Yeah, once one moves past the single driver concept a lot of alignment options become available.
GM
GM
My vote is for the D37 in that room if only for aesthetics. A pair should sound great in there. The taller speakers will sound better but darken the room.
At 70 inches you could invert the bib for floor loading and a little more placement flexibility!
Larry
Larry
The text file you provided, I changed the Ang to corner loading 0.5, changed the horn length to 215cm resulting in a F12 of 19.37hz
Here are the corrected values(for those interested in plotting your own horns):
An externally hosted image should be here but it was not working when we last tested it.
Combined front and rear response:
An externally hosted image should be here but it was not working when we last tested it.
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What is that software? Amazing that it calculated room positioning and speaker layout!
Now it just needs a 100hz front horn!
In all seriousness though, I have been contemplating the benefits of some sort of front horn, from very basic, to complicated.
Not to go off topic though. ScottMoose, do you think this dip at 130hz is a concern, or will it not be as noticeable in real life?
Also, in line with that thought, do the BIB enclosure or any TQWP have this same freq. dip that corresponds with the Impedance spikes? Or can this be mitigated?
In theory, could a mid range horn be used to correct these dips?
I do have a 99dB Ribbon Tweeter which could fill in above 4khz.
See attachments below, (despite being a little too deep in order to get it down to 100hz)
I do have a 99dB Ribbon Tweeter which could fill in above 4khz.
See attachments below, (despite being a little too deep in order to get it down to 100hz)
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I don't think the top end is where you're gonna have the most trouble with this driver in this room.
A couple of hints have already been given
A couple of hints have already been given
To an extent it varies in magnitude depending on room positioning, dimensions, construction, furniture etc. to say nothing of listening position. As does the rest.
Anyway, that's F3, the 3rd pipe harmonic resulting from the under-sized / heavily compromised horn. You could possibly create a very narrow BW front horn to help with forward radiation in that region, but compound horns are generally used differently -usually to fill in a gap between the practical upper-corner frequency of a back-loaded bass-horn and the driver's own mass-corner frequency. The bulk of an additional front horn for that region would probably be more usefully employed on a less compromised back horn in the first place. When you get to very big / long bass horns, then compound starts to come into its own.
Anyway, that's F3, the 3rd pipe harmonic resulting from the under-sized / heavily compromised horn. You could possibly create a very narrow BW front horn to help with forward radiation in that region, but compound horns are generally used differently -usually to fill in a gap between the practical upper-corner frequency of a back-loaded bass-horn and the driver's own mass-corner frequency. The bulk of an additional front horn for that region would probably be more usefully employed on a less compromised back horn in the first place. When you get to very big / long bass horns, then compound starts to come into its own.
HR’s corner loading calculates an infinite corner, not realistic for virtually all apps, so 1pi is normally used and in a stick built, ‘floating’ floor, house like mine even this is a bit optimistic.
??? No, you changed the length to a 242.92 cm tractrix according to the HR input you posted. Atc is wrong also, so according to published design data, your sim is still way off.
GM
One can also increase the BIB's path-length to get it closer to the ceiling to safely allow mid-wall placement as long as it doesn’t go below the driver’s ‘effective’ low corner frequency [Fs*effective Qes/2], which in this driver’s case wouldn’t be an issue except possibly in a cathedral where the bass delay would be too long to be a viable option.
GM
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