My aperiodic design can be extended to an enclosure of volume 30 litres (approximately 1 cu ft) simply by doubling the number of holes drilled in the rear of the enclosure.
Indeed, by proportion, it can be extended to any larger volume. However, 30 litres is already a pretty large enclosure for desk top use!
In the TS-D65F/TS-D65C operating manual ( https://pioneer.b-cdn.net/wp-content/uploads/2017/12/TS-D65F-User-Manual.pdf ) on page 2 there is a picture for correct mounting:
TS-D65F should be mounted on the horizontal panel behind the back seats.
TS-D65C should be mounted in the door.
It is not just the different mounting: Volume in the door is much smaller than the volume behind the back seats - that is why it needs two different Thiele-Small parameters for proper operation.
If the woofer voice coil diameter is 1" (25 mm), than it can handle 45-50 W.
If the woofer voice diameter is 1.5" (38 mm), than it can handle 90 W.
In the Operating manual there is no information about the size of the woofer voice coil diameter.
It is impossible to squeeze the correct TL in only 12 litres volume. Build closed or leaky/aperiodic box.
The high Qts one probably hopeless. The low Qts one might work as highly-tapered ML-TL/TLonken; tapering can reduce line length by >30% and volume by >60% for the same quarterwave frequency alignment. Keep CSA at closed end no less than driver Sd*1.25 (from experience), preferably double that. Then 6.5" 12L volume 1.2m line ~50hz.
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On Page two, the only pic with the D65F mounting is this one A1. Looks like a door trim to me, what do you guys think? Also, how does the super low efficiency affect things when it comes to box size? Is there a relationship? I have observed that the drivers made for smaller boxes usually have stiffer suspensions and low efficiency rating. This one is in line with most good tiny sub drivers. Is there any chance that this could have been made differently? It sounds more articulate and easier to pick bass guitar notes when compared to JL Audio C6
If these drivers turn out to be keepers, I have the space to do a wide, flat box as a splash back on the desk and mount the big screen on the flat box with the speakers either side of the screen, I can make a stepped recess for the TV and I would appear as two columns either side of the screen. I don't know if this would sound any good. The Meet Bros. studio in India has a wall mounted screen with in wall 3 ways either side. For me these speakers are for listening to music, TV, as well as live jamming with the DAW and less about close scrutinising of recording material. In this case I might have space for two drivers per side. I am using a FFA02 amp from one of the vendors here and it can do 150wrms per channel into 8 or 4 ohms due to its built in supply design
I would consider another pair of these speakers for rear channel if they turn out to be keepers
Sorry, I meant 12L as a sealed box. I can fold 3m down to 1 or so. I have good height above the desk available or I can make floor standers for either side of the desk
I like the sound of that!, I do not know much about TL but from what I have been able to gather, length affects tuning? Can this be done to 34hz instead of 50?
1.8m line, posts #6 and #16. What I don't know, is the mathematical relationship between cab volume (or average CSA) and deep bass SPL. If you built the biggest desktop cabs you can comfortably live with -- drivers near ear-level, vents at bottom for a boost, and backed up against the wall -- you might get too much bass... or just enough 😉
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Correct, the door/panel creates a ~leaky sealed box and if there's any sound/whatever insulation, then it's somewhat aperiodic, so for desk/near wall apps using my preferred mobile audio drivers I've added floor to as high as allowed back plates/baffle as wide as allowed with fiberglass insulation in my time (open cell foam preferred nowadays) attached to the backside and pushed close enough to the wall to just barely leave a driver/wall gap.
Yes, please educate yourself and feel free to ask questions if you get stuck on anything.
If you have enough space, floorstander TL is the best enclosure for your woofer. Rule of thumb (very vague, because Thiele-Small parameters are not known): total TL length should be about 1.6 m (total volume about 50-60 liters), with tapper 7:1 to the end opening.
Unfortunately, 34 Hz is out of question.
If MJK's (tapered line effective length) Area Ratio "Table 1" is to be believed, the above 1.6m 1:7 taper will yield ~36hz alignment. 60L would be ~5*Sd CSA at closed end, "classic" TL, but quite large and possibly too far apart for stereo listening while seated at the desk (hearing most sensitive front L/R not direct L/R).
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To all, thank you for helping explain
So far, what I have come to understand is that these drivers appear to be decent modern replacements for those classic record player with tube amp sideboard furniture. The speaker enclosure that you guys sounds much like the big space and perforated Masonite board rear panels
With detailed specs unavailable on these, am I understanding these drivers properly now, just from your thoughts on them?
In these pioneers, the tweeter is on a stem that comes out in the same manner as a phase plug. The edge of the former is exposed. I can't find my calipers, but placing a small ruler behind shows just shy of 1.5". Has rubber roll surround and weighs 850g each. I would like to understand what makes them high Qts
That, for a small desktop ported speaker and deep bass, I should look for a driver with:
1.5" or larger voice coil, high thermal power handling
High BL, high Mms and high Cms
Low Vas
This also sounds like a low efficiency driver, maybe more like a sub driver
That, a TL is an acoustic device where SD = ID and length fixes a tuning frequency It has a Qtc created by the duct effect affecting the air mass in the tube. It has been mentioned that for the TL would need taper to work with these drivers. Would cylindrical not work? I don't understand the why's here
That, going with a TL would mean incompatible with small speaker box size unless some sort of TL and reflex hybrid
So far, what I have come to understand is that these drivers appear to be decent modern replacements for those classic record player with tube amp sideboard furniture. The speaker enclosure that you guys sounds much like the big space and perforated Masonite board rear panels
With detailed specs unavailable on these, am I understanding these drivers properly now, just from your thoughts on them?
In these pioneers, the tweeter is on a stem that comes out in the same manner as a phase plug. The edge of the former is exposed. I can't find my calipers, but placing a small ruler behind shows just shy of 1.5". Has rubber roll surround and weighs 850g each. I would like to understand what makes them high Qts
That, for a small desktop ported speaker and deep bass, I should look for a driver with:
1.5" or larger voice coil, high thermal power handling
High BL, high Mms and high Cms
Low Vas
This also sounds like a low efficiency driver, maybe more like a sub driver
That, a TL is an acoustic device where SD = ID and length fixes a tuning frequency It has a Qtc created by the duct effect affecting the air mass in the tube. It has been mentioned that for the TL would need taper to work with these drivers. Would cylindrical not work? I don't understand the why's here
That, going with a TL would mean incompatible with small speaker box size unless some sort of TL and reflex hybrid
Its is a big box, but can be done 🙂
Thank you for the link, it's brilliant. I am stuck on trying to understand what makes these high Qts drivers. Is there a reason why you prefer mobile audio drivers. I like them as I think a lot of money is really spent on developing the higher end items in an extremely active and competitive scene
Floor standers would have to be an extreme option, as that would mean a desk redesign though but just under a metre folded will look big but acceptable on the desk
I roll back about 2 m from the desk for scrutinising
Since the pandemic I've built or "remodelled" a fair number of them, compact tapered TL or ML-TL with slot vent (search "TLonken"). Just 1-1.5m lines with surprisingly good bass, much better than simple "quarterwave" math might suggest (speed of sound divided by four times line length). Then I came upon planet10 Dave's posting of MJK "Area Ratio Table 1" and wow, 1:5 taper has a ~1.4X multiplier effect on line length -- hence requires just 70% line length, 60% average CSA, 42% volume to reach same quarterwave frequency alignment as 1:1 untapered. (An expanding line, back-loaded-horn, has the opposite effect.) After staring at "Table 1" and using Windows calculator with sqrt function, I reduced the numbers to approximately
1:R tapered TL effective multiplier R^1/4.75
R:1 expanding BLH effective divisor 2-1/R^1/4.75
I don't have a rigorous-enough mathematical explanation for it.
I listen to acoustic instruments so the TL/TLonkens have been tested by ear using tone-sweep and organ/piano/bass-drum/orchestral recordings, NOT AS DEEP AS YOU ARE AIMING FOR. So you should build a longer line and bigger cab, as much as your environment allows.
I think this is an excellent reason, and the fact that overstock can be had for a song. They are also designed to work in harsh, non-optimal environment of relatively small enclosure. I have several: resin-coated-carbon-fiber poorman's Magico; Al2O3 Alumina poorman's Accuton; fiberglass-honeycomb poorman's Eton (made for Eve Audio, spun-off from Adam) that I've also seen as an automotive driver.
More like this Dave 🙂
wchang
I am looking at 6.5" DS18 subs to use in a high power, a small bass reflex desktop as a two-way. Some of the series have very nice sound, up to even 4khz. I am thoroughly impressed with their 10" gen-x which I use for home sub and bass amp
A problem that I have encountered is the tweeter. The PA types seem to be way too sensitive to run with this as woofer
To all, thank you for helping explain........ Thank you for the link, it's brilliant.
You're welcome!
So far, what I have come to understand is that these drivers appear to be decent modern replacements for those classic record player with tube amp sideboard furniture. The speaker enclosure that you guys sounds much like the big space and perforated Masonite board rear panels......With detailed specs unavailable on these, am I understanding these drivers properly now, just from your thoughts on them? Is there a reason why you prefer mobile audio drivers.
Correct, no need to 'fix what ain't broke' and why I prefer them for certain apps such as yours.
I would like to understand what makes them high Qts
That, for a small desktop ported speaker and deep bass, I should look for a driver with:
1.5" or larger voice coil, high thermal power handling
High BL, high Mms and high Cms
Low Vas
This also sounds like a low efficiency driver, maybe more like a sub driver
Easiest to look for low Fs, Vas, high Qts (> ~ 0.4), high Xmax (> ~ 10 mm = high power potential)
That, a TL is an acoustic device where SD = ID and length fixes a tuning frequency It has a Qtc created by the duct effect affecting the air mass in the tube. It has been mentioned that for the TL would need taper to work with these drivers. Would cylindrical not work? I don't understand the why's here.........That, going with a TL would mean incompatible with small speaker box size unless some sort of TL and reflex hybrid
Resonant air column tutorial (lots of links to follow); Sd = pipe i.d. rarely performs properly, so best to ignore such simplications: http://hyperphysics.phy-astr.gsu.edu/hbase/Waves/opecol.html#c1
Line length, taper, sets pipe fundamental; pipe area sets net volume (Vb), acoustic efficiency; adding a vent shortens the line length for a given tuning (Fb/Fp) via air mass loading
Yes, some folks use Sonotube or similar tubes or tubes within tubes to create tapered TLs
Its is a big box, but can be done
Yes, though ideally the pipe would expand since it's a high Qt driver, i.e. be a mass loaded horn = tapered quarter wave tube (TQWT), which can be tapered in either direction, so added ML TQWT for inverse tapered and ML horn for positive taper
Anyway, lots to learn if wanting to properly design these types of speaker alignments.
You're welcome!
So far, what I have come to understand is that these drivers appear to be decent modern replacements for those classic record player with tube amp sideboard furniture. The speaker enclosure that you guys sounds much like the big space and perforated Masonite board rear panels......With detailed specs unavailable on these, am I understanding these drivers properly now, just from your thoughts on them? Is there a reason why you prefer mobile audio drivers.
Correct, no need to 'fix what ain't broke' and why I prefer them for certain apps such as yours.
I would like to understand what makes them high Qts
That, for a small desktop ported speaker and deep bass, I should look for a driver with:
1.5" or larger voice coil, high thermal power handling
High BL, high Mms and high Cms
Low Vas
This also sounds like a low efficiency driver, maybe more like a sub driver
Easiest to look for low Fs, Vas, high Qts (> ~ 0.4), high Xmax (> ~ 10 mm = high power potential)
That, a TL is an acoustic device where SD = ID and length fixes a tuning frequency It has a Qtc created by the duct effect affecting the air mass in the tube. It has been mentioned that for the TL would need taper to work with these drivers. Would cylindrical not work? I don't understand the why's here.........That, going with a TL would mean incompatible with small speaker box size unless some sort of TL and reflex hybrid
Resonant air column tutorial (lots of links to follow); Sd = pipe i.d. rarely performs properly, so best to ignore such simplications: http://hyperphysics.phy-astr.gsu.edu/hbase/Waves/opecol.html#c1
Line length, taper, sets pipe fundamental; pipe area sets net volume (Vb), acoustic efficiency; adding a vent shortens the line length for a given tuning (Fb/Fp) via air mass loading
Yes, some folks use Sonotube or similar tubes or tubes within tubes to create tapered TLs
Its is a big box, but can be done
Yes, though ideally the pipe would expand since it's a high Qt driver, i.e. be a mass loaded horn = tapered quarter wave tube (TQWT), which can be tapered in either direction, so added ML TQWT for inverse tapered and ML horn for positive taper
Anyway, lots to learn if wanting to properly design these types of speaker alignments.
I have no argument with Randy's basic understanding, however I would regard a classic 'radiogram' enclosure such as he describes as an 'open-backed box'.
The perforated Masonite board is incorporated simply to keep inquisitive fingers at bay while providing adequate heat ventilation (important for tubes).
Properly designed aperiodic loading will offer greater resistance to the flow of air than is provided by the large openings in a radiogram back.
EDIT: The quote is attributable to Randy and not GM - I am addressing Randy and not you GM!
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We'll have to 'agree to disagree' 😉 in that there's an audible difference with/without the pegboard.
Acts sort of like an OB in that the back provides little resistance. The U-frame wil have a resonance related to the depth of the cabinet.
dave