6,5" to 7" midwoofer for sealed enclosure

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jerome69

jerome69

Member
Joined 2008
Why (2xSPH 176) or (2xP17) or (2xCA18RNX/RLY) etc. + DT300+WG ?
The crossover will be very simple !

Or why don't you test a transmission line ? The best load for a driver, i have heard because you have the least boxy sound.
See this kit : Kits Monacor - Kit d'enceintes DIY Monacor MINDSTORM

Choose your drivers and we can see how to do a TL. Drivers with a Qt higher than 0.4 are good for TL (SPH176, CA18RLY etc. )

Cheers.

martinbls said:
Hi everyone,
thanks a lot for all your replies!

To some of your thoghts:
Jeromes idea of a true 3-way is certainly a nice one, but I just remembered that my listening room is just a bit too small for such a speaker. Another thing is that I really like to hear a huge soundstage coming from a small speaker, in germany we used to call it the "Aha!"-effect :) I guess that's why I'm ditching the idea of two 8" drivers also. Simply too big, unfortunately.

Davids version of a FAST is intoxicating for sure, especially the one with the 6,5" CSS woofer in a sealed enclosure. Problem is, I never heard those small fullrangers before. That means it would be a complete new area to discover. I know serveral 1" dome tweeters and I also tried a few 6,5" midwoofers in the past (Monacor SPH-176, Monacor SPH-165KEP, Audax HM170CO, Vifa P17WJ0008, Vifa PL18WO-09-08, Peeless 830874, Eton 760/37 HEX, Mivoc WPP180), so I have an idea of what to expect from such a simple 2-way design.

Originally, after a long term test session including all the midwoofers mentioned above, I decided that I liked the........ drum roll...... Vifa P17WJ best!
Others of the above drivers had better bass, some had better (clearer or more transparent) mids, but the P17 was the most enjoyable driver with the greatest versatility and the best all-round character. Good mids, good lows, just musical. Not the very best of all worlds, but highly enjoyable and forgiving enogh for most styles of different music (bad recordings included). Also, it was a driver very easy to work with regarding the x-over design.

I ended up selling all these drivers because I bought a completely different speaker at a good price second hand.
Nowadays, the P17 is discontinued (I know, Madisound offers them, but it would be quite expensive to ship a bunch of these over to germany) but I'm starting to think about this kind of speaker again. That's why I'm intersted in other 6,5" drivers I haven't tested myself, like the Seas CA-series.
The idea with the sealed design came up mainly because I listened to the low frequency range of a 10" Vifa driver in a sealed enclosure (the bass of a Martin Logan SL3) and I wanted to combine the ability to produce the nice clean mids and the huge but precise image of a good 6,5" driver with the strong, tight and absolutely not overblown bass of a sealed enclosure. All together in a small, inexpensive package!

Oh my, tough customer again...

But you guys, I think I might go for the P17 from Madisound because I already know this driver quite well and I like it. 2,5-way design, 20l BR for each driver (with a tad more stuffing than usual), a nice tweeter (Seas 27TDFC or Vifa HT 270 VF/6) and a VERY simple crossover design.

Or perhaps a very similar project, the Zaph Waveguide TMM with the 27TDFC and two CA18RNX (Zaph|Audio).

I like simple crossovers. I was never satisfied with higher order crossovers when it comes to the ability of drawing me into the music emotionally. Higher orders may lead to a more "correct" behaviour of the drivers responses, but to me the music itself never sounded "right" that way. Please note: This is a highly personal opinion!
That's why I'm not looking for a driver that produces a good low frequency range only. The midrange is still the most important part of the spectrum. At least that's what I think...
Click to expand...
 
S

sreten

R.I.P.
Joined 2003
lduarte1973 said:
i dont like how vented boxes sound, if you want low extension get a sealed sub
Click to expand...

Hi,

That is an absurd statement, there are so many different vented alignments,
and for low extension with SPL capability, vented works. Personally I like quasi
1st order roll-off vented alignments optimised for F-6 and F-10. Making a 6.5"
driver effectively a 13" (sealed vs. vented) at vent frequencies is a big plus.

Extension without SPL capability is pointless, why good vented tuning works.

rgds, sreten.
 
4

454Casull

Member
Joined 2004
sreten said:
Hi,

That is an absurd statement, there are so many different vented alignments,
and for low extension with SPL capability, vented works. Personally I like quasi
1st order roll-off vented alignments optimised for F-6 and F-10. Making a 6.5"
driver effectively a 13" (sealed vs. vented) at vent frequencies is a big plus.

Extension without SPL capability is pointless, why good vented tuning works.

rgds, sreten.
Click to expand...
Did you mean a 9" driver?
 
T

Tytte71

Member
Joined 2010
Hi Martinbls. Unfortunately a 2-way sealed 20l design is simply not feasible if you want to play some music on them with bass at even modest levels. There are very good reasons for why small speaker almost always are made BR.

I would however like to suggest a couple of design that could make (in my opinion) a good design:

1. Use a couple (or better four) of Exodus Anarchy in a 20-30l sealed and power these with a dedicated subamp with eq (there are alternative drivers for this). A Seas T18RE/XFCTV2 could cover i.e. from the baffle step frequency up. You could have a system that can play with realistic level at very high quality. Threeway but very useful in small rooms and for nearfield use.
2. My fav for this small cabinet size would be to use two 6,5" Scan Speak Illuminator midwoofers in a 2,5way system with passive radiators (I know it is not closed cabs, but some of the drawbacks with BR, such as port resonances and space needed for BR tubing is avoided). Pair the SS with the Seas 27TBCD/GB-DXT for good dispersion control and you have got yourself a very very nice setup that would play quite loud and at high-end quality - not bad for a "bookshelf".

Hope that was useful
cheers,
 
A

alspe

Member
Joined 2007
Tytte71 said:
There are very good reasons for why small speaker almost always are made BR.
Click to expand...

And that is mainly commercial point I think. People are tend to prefer amount, not quality. Short audition increases that, in big hifi show where environment is not as quiet as in your home, rooms maybe big, background noise etc etc. It's easier to hook up in punchier bass.

That is true that from 5 litre speaker you get almost no bass without BR but 20 liter is another thing. Good 7"/8" in 20 l closed might be good in right speaker placement and in smallish room. It play tuneful bass. With small enclosures you cannot tune port so low that group delay etc goes to inaudible frequencies (20 Hz).
Passive radiators do even worse transient response than BR.
 
DDF

DDF

Member
Joined 2004
alspe said:
Are you sure? Quite low Qts, deep bass really.
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"Title: Measured Data"
"Area (Sd): 150.00 sq cm"
0.206 "RMSE-free Ohms"
31.904 "Fs Hz"
5.536 "Re Ohms[dc]"
38.919 "Res Ohms"
2.812 "Qms "
0.400 "Qes "
0.350 "Qts "
0.234 "L1 mH"
0.570 "L2 mH"
2.045 "R2 Ohms"
0.174 "RMSE-load Ohms"
33.198 "Vas liters"
23.689 "Mms(Sd) grams"
1050.539 "Cms(Sd) æM/Newton"
8.107 "Bl(Sd) Tesla-M"
86.136 "SPLref dB "

12L and 0.2 to 0.5 ohms pending choice of inductor resistance, and stuffing from heavy to lined walls, Qtc = 0.61 to 0.69 and Fb = ~57 to 65 Hz.

The woofer has good throw. If you need more/deeper, need a bigger driver and box. In a small sealed footprint, it has pretty good reach without dynamic or amp power sucking loss of sensitivity. Sounds good too.
 
A

alspe

Member
Joined 2007
I don't have sim program right now,

CA18RLY fits nicely into 22 litre sealed but how looks CA22RNY in same enclosure? It has worse Qts for sealed but 8 Hz lower Fs. Which would be better in real life, both do fine 2200-2700 Hz XO. (maybe 0,30 Qts is really too low for sealed).
 
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M

mhelin

Member
Joined 2003
alspe said:
Thanks for reply. If you can give more info of your designs, please send PM if not write in this.

Maybe I'm buying this and this and make around 20 litre standmounter.
Click to expand...

That second this seems to be a Seas version of DX25, interesting.

How about using the CA22RNX with a higher Qts (good for sealed but may require larger box, 30 - 35L might be enough if stuffed well enough).
 
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A

alspe

Member
Joined 2007
^ CA22RNX is a another beast if box volume could be around 32 liter. It gives 10 Hz lower F3 and 5 Hz lower F10 than CA18RLY in 22 liter (which is a lot in paper but who knows how important in room). I think big difference would come from bigger Sd. Though 22RNX has something peaky at 3000 Hz so I don't believe it would work in 2way as good as to others mentioned.

CA22RNY in 22 l reflex (38 Hz tuning) gives exactly same bass depth than 18RLY in closed so I don't go there, worse group delay, smaller cone excursion, so I pick sealed if have to choose. 22RNY in closed (22 l) is not good, Qts 0,30 cuts basses off. F3 over 80 Hz and F10 50 Hz.

So as compromise, CA18RLY seems find if we think F10, volume around 22 litre and mids reproduction up to 2300-3000 Hz. Fs could be couple of Hz's lower, but have to live with that.:)
 
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