MarkAudio CHP-90 Enclosure Options

[LeifB60]

You're welcome!

If you tune it below Fs it will and if you want the max power available for [mid] bass 'slam', then the pioneer's Vb = Vas/1.44, Fb = 1.56x Fs prosound alignment dating from at least 1937 with the introduction of the Lansing Iconic recording/playback studio monitor is the way to go.

13.9 litre and 75hz.
Thanks..

 

[GM]

I think that a folded TL would be the best for me for the CHP-90 but I also think I would need some help to do it!
Any practical suggestion on how to proceed?

Hmm, based on the following IME, an inverse tapered one is best overall since its 'system' specs (Qts + Rs) 'naturally' requires a large/long vent for max power handling in a BR alignment:

FYI/FWIW, IME and proved to my satisfaction when 'proofing' MJK's MathCad design programs against some of my own Tower/Column alignments from 'way back when', the vented TL (closed pipe) alignment (aka MLTL) range from ~0.312 - 0.624 Qts' seems technically good enough, i.e. from Keele's 6th order assisted bass reflex to his Extended Bass Shelf (EBS) alignment.

While the 'sweet spot' (mean) is a ~0.4412 Qts', a 'close enough' simple guideline is:

~0.403, Vb = Vas, Fb = Fs (constant tapered MLTL)

< ~0.403, Vb = < Vas, Fb = > Fs (inverse tapered MLTQWT)

> ~0.403, Vb = > Vas, Fb = < Fs (expanding taper MLTQWT/MLhorn)

Qts' = Qts + any added series resistance (Rs): http://www.mh-audio.nl/Calculators/newqts.html

 

[LeifB60]

Hmm, baserat på följande IME, är en omvänd avsmalnande en bäst överlag eftersom dess "system"-specifikationer (Qts + Rs) "naturligtvis" kräver en stor/lång ventil för maximal effekthantering i en BR-uppriktning:

FYI/FWIW, IME och bevisade till min tillfredsställelse när jag "proofed" MJK:s MathCad-designprogram mot några av mina egna Tower/Column-justeringar från "way back when", den ventilerade TL (closed pipe)-inriktningen (aka MLTL) sträcker sig från ~0,312 - 0,624 Qts verkar tekniskt bra nog, dvs från Keeles 6:e ordningens assisterade basreflex till hans Extended Bass Shelf (EBS) justering.

Medan "sweet spot" (medelvärde) är ~0,4412 Qts, är en "nära nog" enkel riktlinje:

~0,403, Vb = Vas, Fb = Fs (konstant avsmalnande MLTL)

< ~0,403, Vb = < Vas, Fb = > Fs (omvänd avsmalnande MLTQWT)



Qts' = Qts + eventuellt tillagt seriemotstånd (Rs): http://www.mh-audio.nl/Calculators/newqts.html

If you have time.
Can you make a hornresp txt file for me. Make me understand. Please.

 

[GM]

Some copy/pasted info I've posted over the years in one form or another:
Margolis-Small's HP 67/97 & 41C calculator program if wanting all the math for vented, sealed: http://www.aes.org/e-lib/browse.cfm?elib=3902

T/S max flat:

net volume (Vb) (L) = 20*Vas*Qts'^3.3

box tuning (Fb) (Hz) = 0.42*Fs*Qts'^-0.96

Find its net Vb, then its i.d. area (CSA); driver vertical location + offset + bottom plate thickness sets i.d. height

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':
Z = (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: Z = (L)x ~0.651, 0.714, 0.848, 0 (bottom)

I only use/recommend ~0.75"/1.8 cm no void plywood or similar, so no need to brace beyond basic vertical, horizontal + driver brace, so just the 'outline' of Dave P10's bracing schemes, but until we reach concrete weight, can't go wrong with his if the extra woodworking isn't a big deal like it always was for me and others with severely limited build timeframes.

Addendum:

https://www.diyaudio.com/community/threads/markaudio-chp-90-enclosure-options.391468/post-7178128

https://www.diyaudio.com/community/threads/markaudio-chp-90-enclosure-options.391468/post-7180005

https://www.diyaudio.com/community/threads/markaudio-chp-90-enclosure-options.391468/post-7180042

 

[GM]

If you have time.
Can you make a hornresp txt file for me. Make me understand. Please.

??? I've posted a number of them for 'FR' drivers already you can use for templates, not to mention a number of design tutorial postings to help quickly find a technically viable alignment.

 

[LeifB60]

??? I've posted a number of them for 'FR' drivers already you can use for templates, not to mention a number of design tutorial postings to help quickly find a technically viable alignment.

Thank you. I am sorry. But I will fix it.

 

[GM]

You're welcome! No need to be 'sorry', I realize we have a language barrier issue, hence the ??? to get some clarity/understanding, including what are you going to 'fix' ??

 

[GM]

Hmm, made me go back and look at this and found a potentially very confusing error (bold)!

FYI/FWIW, IME and proved to my satisfaction when 'proofing' MJK's MathCad design programs against some of my own Tower/Column alignments from 'way back when', the vented TL (closed pipe) alignment (aka MLTL) range from ~0.312 - 0.624 Qts' seems technically good enough, i.e. from Keele's 6th order assisted bass reflex to his Extended Bass Shelf (EBS) alignment.

While the 'sweet spot' (mean) is a ~0.4412 Qts', a 'close enough' simple guideline is:

~0.403, Vb = Vas, Fb = Fs (constant tapered MLTL)

< ~0.403, Vb = < Vas, Fb = > Fs (inverse tapered MLTQWT)

> ~0.403, Vb = > Vas, Fb = < Fs (expanding taper MLTQWT/MLhorn)

Qts' = Qts + any added series resistance (Rs): http://www.mh-audio.nl/Calculators/newqts.html

 

[LeifB60]

Yes, that is what I have to fix.
But i dont understand most of it.

 

[GM]

OK, I don't know how to make it easier other than go back to this box formula (20*Vas*Qts'^3.3) and make (3) sims in WinISD/whatever with all the same specs except one has a 0.403 Qts, one with 0.38 Qts and one with a 0.42 Qts and compare to what I posted concerning Vb, Fb where < = less than and > = more than

 

[LeifB60]

OK, I don't know how to make it easier other than go back to this box formula (20*Vas*Qts'^3.3) and make (3) sims in WinISD/whatever with all the same specs except one has a 0.403 Qts, one with 0.38 Qts and one with a 0.42 Qts and compare to what I posted concerning Vb, Fb where < = less than and > = more than

I start with formula 20*Vas*Qts'^3.3
Qts 0.364 original. Vb 14.24 l
Qts 0.380 give me Vb 16.41 l
Qts 0.403 give me Vb 19.93 l
Qts 0.420 give me Vb 22.80 l

 

[GM]

Hmm, from here I 'thought' I copied both formulas to calculate/compare, but in my haste, didn't , so need to do these for a complete comparison of what I wrote up: box tuning (Fb = 0.42*Fs*Qts'^-0.96)

 

[LeifB60]

0.364 Fb=53.78hz
0.380 Fb=51.60hz
0.403 Fb=48.70hz
0.420 Fb=46.87hz

 

[Elias Zacharopoulos]

Seeking around for ideas about CHP-90 cabinet I bumped into this
http://diyaudioprojects.com/Gallery/displayimage.php?album=2&pid=685#top_display_media
for

Seas FA22RCZ Fullrange in Open Speaker Cabinet

another driver that I like very much but ... too expensive for me.

Elias

 

[planet10]

A large straight transmission line (kinda short with no mass loading).

dave

 

[Elias Zacharopoulos]

Dave

If they sounds .... not the most important how we can call them. Maybe my way of looking at things is not too pedantic but "white cat, black cat, the point is to catch the mice"

Elias

 

[LeifB60]

Perhaps SB20FRPC30-8 is cheap enought for you. 8 inch. I have not heard it. But I heard good things about them.
I have a pair of SB Acoustics SB16PFC25-8 and the sound is very good. I paid only 32 euro.

 

[Elias Zacharopoulos]

But I have already buy very recently CHP-90. Nandappe use it very recently and had uploaded videos on Youtube

Elias

 

[LeifB60]

Go for A CHP-90. 😉

 

[Elias Zacharopoulos]

Go for A CHP-90. 😉

but I have it already . I don't have enclosure to install on it. Nandappe has started a new thread
https://www.diyaudio.com/community/...justable-duct-no-sound-absorber.392346/page-1
and if my experiment with a "sealed box" with Passive woofer fails, then I will build that. Sound very attractive to my taste as I was listening to that in Youtube.

Elias