Thanks for the new driver (hopefully not sarcastic 😱 ) proposals, but the drivers are set:
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.
yes they are really good.
the only downside is the Volume they need in reality.
you can't simulate or design a system without buying them.
W12CY001 factory TSP Vb: 3,75L real TSP Vb: 9,6L +256% increase
W22EX001 factory TSP Vb: 55L real TSP Vb:78L +41% increase
I really would liked the idea having the W26EX001 in BR but as the homepage states 88Liter in SBB4.... and when i need to add volume somewhere between 41% and 256%.... so i droped this idea.
the only downside is the Volume they need in reality.
you can't simulate or design a system without buying them.
W12CY001 factory TSP Vb: 3,75L real TSP Vb: 9,6L +256% increase
W22EX001 factory TSP Vb: 55L real TSP Vb:78L +41% increase
I really would liked the idea having the W26EX001 in BR but as the homepage states 88Liter in SBB4.... and when i need to add volume somewhere between 41% and 256%.... so i droped this idea.
Someone told me some of the SEAS drivers with phase plugs couldn't be used in a closed box because air could leak past the phase plug. I never bought any to try; has anyone had this "air leak" happen with SEAS? Ages ago; most of my designs were large bass reflex with low tuning. These days; I mostly do closed box or closed box with Aperiodic vent. I no longer have a very large listening space so larger boxes are not practical. I would still do it for others though. A very well designed bass reflex does not have all the negative problems many people report and so therefore avoid. Like everything else; if it's done properly; BR can be a very good sounding solution (NO boominess, vent noises, bloated, muddy or any other undesirable effects). It's a shame when the OEM TSPs are way off; that's why it's always good to have 3rd party testing and reviews.
i heard this story too that you can't use phase plug drivers for closed.
my W12CY001 has a simulated Fb=73,12hz. in the box i have a Fb=70,9hz.
i have a difference of 3%., its ok. i was able to reach my desired alignment for the closed box.
so in my opinnion its doable without problems.
my W12CY001 has a simulated Fb=73,12hz. in the box i have a Fb=70,9hz.
i have a difference of 3%., its ok. i was able to reach my desired alignment for the closed box.
so in my opinnion its doable without problems.
I’ve used W16NX in a 5L sealed box. There seems to be some air leakage past the phase plug detectable at large cone excursions (some audible chuffing). I found this when using large amplitude LF test tones, I haven’t detected anything obvious under normal music listening conditions.
Andrew.
Andrew.
Audible chuffing would be a concern. I'm not sure I see a clear difference between closed and reflex in regard to a small leak.
My guess is that the chuffing is a result of pressure differences between the front and back of the cone. Reflex cabinets may have smaller pressure differences due to the vent, a larger cabinet and lesser cone displacement.
Interesting observation. I was just thinking about whether those things are what oldspkrguy's acquaintance was talking about.
It may be true that the box makes a contribution and the driver stops moving (much) in one band of frequencies, but at that time the cone is holding back considerable out of phase energy.
It may be true that the box makes a contribution and the driver stops moving (much) in one band of frequencies, but at that time the cone is holding back considerable out of phase energy.
Yes, I agree frequency will be a factor. The leakage path may also have a resonant frequency above which it is effectively no longer a leak. Unfortunately I dont have the maths to estimate the likely value.
Looks great Richard, congratulations!
Sorry I havn't read the whole thread, but just wondering if you compared the Seas mids with The BMS 5 inch which are designed for small sealed box (5 to 11 litres)?
http://www.bmsspeakers.com/fileadmin/bms-data/product_data_2012/bms_5s117_t_data_2012-01.pdf
Even at 110dB SPL @ 1 meter 2nd and 3rd harmonic distortion is -40dB to -45dB over the 300Hz to 2,000 Hz band.
Thanks and happy New Year to all.
A.
At and near the tuning frequency, the BR is supposed to have less cone movement and the majority of the output is at the port...At least, in a classic BR design that is one of the advantages. Of course, below that; the cone can EASILY get out of control so it always best to have an electronic/active HP to prevent over excursion. My old amps and receivers usually had a "rumble" filter especially designed for warped LP records. This was typically a 2nd order or higher order HP active filter below 20 Hz. My new Yamaha integrated has a phono input but no "infra-sonic" filter. Luckily, my subwoofer plate amp DOES have one; it is at 12 Hz and is 4th order fixed (can not be defeated).
Anyway; I think the idea here is that the BR port relieves some back pressure on the driver cone even above the tuning freq. so any phase plug or other VC "front facing vent" is less obtrusive than that of a closed box. I never proved it or tried to measure it; just passing along info from a reliable source...
Anyway; I think the idea here is that the BR port relieves some back pressure on the driver cone even above the tuning freq. so any phase plug or other VC "front facing vent" is less obtrusive than that of a closed box. I never proved it or tried to measure it; just passing along info from a reliable source...
I don't think that's how it works. Remember, the port works because there is an air mass in the port with very real inertia. Think of it as solid thing with real mass, which of course is why you can use a passive radiator instead. So, we have this solid mass "moving" back and forth very quickly in the port such that it imparts pressure to the box every bit as much as we know the speaker cone itself does. When both the speaker diaphragm and air mass move inward (in phase) we have a pressure spike within the box. How much is exactly proportional to the SPL created. Higher SPL=higher internal box pressure, whether or not the box is sealed or ported. Given the ported box has higher SPL in the passband concerned, it must also have a higher box pressure. My .02 anyway.
That's the problem with 'reliable sources' 😉
The fact that the cone is being supplied with a signal but is hardly moving just goes to show that it is up against considerable pressure. Pressure that will take advantage of a leak like that.
The fact that the cone is being supplied with a signal but is hardly moving just goes to show that it is up against considerable pressure. Pressure that will take advantage of a leak like that.