| OTMOPO3OK |
I'm building B200 OBs so i need to augment it with 15" OB woofer (doing 40-200Hz duty). It will either be just a plain small baffle or a stuffed U baffle.
My room is 16'x11'x9' with speakers along a longer wall (1-2' off the back wall) so I'm wondering if i should buy 1 or 2 woofers per side? I'm a bit of a "fast+clean bass" head but i don't listen too loud, i just want doublebass to sound like it should. I'm SO tired of boomy bass with my room modes and TL sub. I have active XO + EQ so matching SPL is not a problem.
Music preferences are mostly Jazz, Prog. Rock.
Here are my options:
Eminence Alpha-15A $59
*Frequency range: 46-3,500 Hz
*Magnet weight: 25 oz.
*Fs: 41 Hz
*SPL: 97 dB 1W/1m
*Vas: 9.2 cu. ft.
*Qts: 1.26
*Xmax: 3.8 mm
http://www.partsexpress.com/pe/psho...407&ctab=2#Tabs
Eminence Delta-15LFA $96
*Frequency range: 42-3,200 Hz
*Magnet weight: 56 oz.
*Fs: 41 Hz
*SPL: 96 dB 1W/1m
*Vas: 6.6 cu. ft.
*Qts: 0.58
*Xmax: 4.8 mm
http://www.partsexpress.com/pe/psho...417&ctab=2#Tabs
Knight-15 $50
Frequency Response: 35 to 4500hz
FS 35 hz
VAS 4.48
Qts 1.006
Xmax 4.5mm
Magnet weight: 50 oz.
http://www.musicsupplycenter.com/Pr...tCode=813%2D013
Warrior-15 $35
Frequency Response: 35 to 4600hz
FS 36 hz
VAS 8.29
SD 143.13
Qts 0.826
Xmax 4.5mm
Magnet weight: 50 oz.
http://www.musicsupplycenter.com/Pr...tCode=813%2D021
Mach MAW-15 $79
Fs = 26 Hz
Qts = 0.32 (Using only 1 VC increases Q)
VAS = 129 litres
Xmax = 13 mm
http://www.mach5audio.com/index-2.html
And of course:
Silver Iris Augie $150
Fs: 27.0 Hz
SPL: 88.7 dB 1w/1m
Qt: 0.92
Vas: 250.3 liters
Xmax: 7.15 mm
Magnet weight: 67ounces
http://www.hawthorneaudio.com/drivers.htm
Can Qts be too high?
Visaton BGS 40 has Qts 0.4
http://www.visaton.de/en/chassis_zu...er/bgs40_8.html
and people reported it sounding very good in OB while at the same time MJK really liked Alpha15A for their high Qts=1.26.
http://www.quarter-wave.com/Project07/Project07.html
I chose drivers with accordion surrounds since I believe low excursion sounds more accurate but will 3.8mm Xmas be enough? (Alpha15)
And finally the $300 question should i bother with all these cheap drivers of just get 2 Augies and a peace of mind? But then maybe at such price i should be looking at better drivers than Augie?
I wanted to save money with Alpha15 but if I need 2 of them to match the capability of 1 Augie then i'd rather get Augie ?!?
Suggestions?
Thank you. |
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| OTMOPO3OK |
Here is another driver that i read very good review about :
GOLDWOOD GW-1558 15" PRO WOOFER $45
* Frequency response: 31-2,500 Hz
* Magnet weight: 50 oz.
* Fs: 31 Hz
* SPL: 95.6 dB
* Vas: 14.19 cu. ft.
* Xmax: 3.9mm
* Qts: .63
http://www.partsexpress.com/pe/psho...tnumber=290-384 |
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| tinitus |
This MAXprofessional PR20120 is not exactly cheap, but on the other hand its a 20" and looks interesting fore dipole
Its a canadian, so you should be able to find it somewhere
http://www.pa-direct.co.uk/driverpd..._6.5neo_mid.pdf
That WARRIOT-15 do look nice and a could be a bargain at 35 USD, and might work fine if it dont distort too much |
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| ttan98 |
| Martin King uses Eminence Alpha 15" with good result, visit his website and read his explanation. |
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| OTMOPO3OK |
Thanks everyone for your input,
Ciares seem fishy and even more expensive than Augie. Augies to me right now seem like perfect OB drivers so if I were to splurge $300 i'd get them, anything more expensive is not necessary.
However the main point of this post is to get my feet wet with OB bass so i highly desire to get some *excellent* drivers in $50 range.
I'm sure if i really like what i hear i'll buy Augies in couple of months and use the less expensive drivers to make a ripole sub, so they won't go to waste.
However Knights and Warriors seem to 'scream' BAD QUALITY (glue on 50% of drivers' surrounds) and most specs lie.
Right now it seems i have 3 major contenders based on different recommendations i read:
GOLDWOOD GW-1558 $45 Qts:0.67
Pyle PPA15 $47 Qts:0.67
Eminence Alpha-15A $59 Qts:1.26
I always felt that Alphas had a weak motor and weak surround and Dick Olsher confirmed my suspision when he said that Q factor was just too high -> less control, all in a race for lower extension. I don't want that. So I think i'm ruling out Alphas due to their 'too high' Qts and weak damping. He also mentioned that Q factor should be closer to 0.6 (he even damped Augies with 25Oohm resistor Surprised).
http://www.enjoythemusic.com/magazi...ker_project.htm
I've seen PPA15 being used for U,H dipole, ripole sub (<80Hz) duty by several people over the years on different boards but i just have a 'gut feeling' they ain't good in midbass region. (from someone's comment of their rising, bumpy response higher).Plus i just feel a driver with cheesy picture on the front can't sound good up higher.Smile
Brad convinced me from his 'extreme' testing that Goldwoods can take a beating and sound great (and he is hard to please he says) :
http://www.hawthorneaudio.com/forum...poor+mans+augie
So at least I'm not worried about Xmax there. I don't know anything else about these drivers (manufacturer doesn't even provide freq. plot) but for some reason i'm still drawn to them. I've heard about the other 2 drivers but i learned about Goldwoods just today and yet after Brad's review i feel they deserve a chance. I' falling for them right now the most. Embarassed
PS: Both PPA15 and 1558 have Qts:0.67 just like Dick Olsher recommended.
BTW i've read that Eminence posts it's Xmas peak values so Alphas 3.8mm is in fact 7.2mm total.
I suspect that PPA15's 6mm is total while i'm not sure about Goldwood's 3.9mm.(i hope it's only one way) But from the review it seems that's more than enough for them.
What do you think? |
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| panomaniac |
I use the Selenium 15PW3 on my "Lounge Lizard" OBees. Very nice driver. QTS of .6 which gives a nice combo of bass and control in OB. The driver does well up into the midrange, tho I don't use it here.
http://www.partsexpress.com/pe/psho...r=264-338&DID=7
Needs about 6~8dB bass boost on my baffles. |
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| OTMOPO3OK |
panomaniac,
How is the extension on that Selenium? I've been looking at it too.
It says Xmax of 3mm. Is it one way or both? Is it enough? How loud can you listen till distortion kicks in?
Bass Boost is fine everything is active. |
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| DeonC |
Zalytron has a 12" woofer called the 1200CP. Specs are an Fs of 18.75Hz, a Qts of 0.678 and an efficiency of 89dB/w. It sounds like it could be really nice. And at US$45-00 it is right in your price bracket. Have a look (it is second from the bottom):
Zalytron Woofers page
Enjoy,
Deon |
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| tinitus |
If I should choose one of the two Emminence, my pick would be DELTA-15LF(A)
KAPPA-18 looks better with low Fs=28hz, allthough a bit expencive it would be my choice rather than double 15" with higher Fs
"Augie" has lost a lot of sensitivity, and they must calculate with plenty of room gain |
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| OTMOPO3OK |
Very interesting suggestions guys
Thank you,
Looking into them...:D |
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| tinitus |
About "Augie" - it might be worth to mention that its intended to be used only below 100hz with a plateamp and another 15"(IRIS), and a quite different setup
My guess is that you will use the woofer passive and a bit higher with your B200 (or Hemp ?) - so it would be nice to have some exstra SPL to take care of BSC :) |
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| OTMOPO3OK |
Tinitus, my setup is fully active computer controlled XO + EQ so cranking up low SPL driver is not a big deal.
As a matter of fact i've seen Augie being used with B200 as high as 300Hz with what appears to be good results. Who knows?!!
Rick, thanks for very informative links.
While the physics of this is unknown to me yet that makes driver selection even more confusing.:boggled:
And transient response is very important, almost on to of my list. |
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| tinitus |
How I evaluate it, and "narrow" it down...
Fore efficiency, NO EQ and good transient response a big 18" woofer, the KAPPA-18, but thats just me
The more "modern" and less efficient alternative - in this respect I find the Augie a bit "vintage" and outdated (sorry), and an alternative could be the cheaper DAYTON 15" IB SUB, Qts=0.65, Fs=20.8,
Very interesting OB driver with nice low Fs that could be exspected to go very deep
just tell me if I talk rubbish
:) |
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| OTMOPO3OK |
18" would be way too big for my room but i get what you are saying about efficiency.
From what i know Dayton 15IB has a sharp drop off at 700Hz so it's not really suitable for XO at 150-200Hz. It's a purely a sub driver.
Regarding the Sub:
I thought that dipole bass can't go lower than my room supports?!?!
My room is 16ft so the lowest note is 35Hz, i figured any driver with Fs<35Hz is good enough. Do i really need Fs=20Hz? |
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| tinitus |
OK, but a 35hz woofer rolls off much ealier than a 20hz woofer, low Fs is very important - its also about phase, meaning that any early rolloff will cause phase problems
Of PA drivers I wont choose nothing less than 18", to get low Fs and better bass response
That your room cant hold anything below 35hz, doesnt mean that it shuts down completely below that, it will just be at lower level
If I remember correct, you have said that you dont play very loud but want the best of refinement and definition - then it could be of advantage to let the fullrange driver roll off by itself, and in that case you might just need the sub driver
But I know, its not that easy
BTW... why do you think that 18" is too big fore your room ... it will match your fullrange very well, and used in OB you should have no problem with ressonanses, and it wouldnt need much baffle either, and with the size and medium Qts=41 you will have well controlled bass
I wont argue any more, but will be interested in your progress
Oh, yes, if you want it small you could just make a small closed sub and mount the fullrange in a small OB, but it will not have the well defined bass like a pure OB |
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| panomaniac |
| quote: | Originally posted by OTMOPO3OK
How is the extension on that Selenium? |
I think it is 3mm, but I rarely even see it move. Just on electronic stuff, like Brian Eno, then it really pumps.
The Selenuim has a progressive spider, so it will pretty much keep you out of trouble. It's meant to take a beating. With 100WPC behind it playing very, very loud I never heard it compress or distort, but that's partly the OB thing.
Really I should be running 2 per side, like Martin does with his Alphas. But that would be mighty big in my little living room. The friend who sold me this pair runs 2x18" per side. Whatever works! |
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| panomaniac |
| quote: | Originally posted by tinitus
Take a look, and tell me the difference between the two, Selenium and the Warrior |
Good eye, tinitus. :cool:
They sure look a lot alike. T/S paramaters are different, tho. For the price I would like to have a look at it. Too bad none are in stock.
Could be a real fun OB driver. |
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| Poindexter |
I would not neglect the Dayton IB385.
Catalog Page
It's specifically designed for almost this exact duty, and I get some fantastic results in WinISD in the infinite baffle (several thousand litre sealed box). Reasonable price, too.
I have a 'dream rig' going on in me tiny brain right now, that uses a line array of 4 JXR6s on each side, and a pair of IB385s in a manifold in each upper corner, backing into the attic space. +0, -3dB at 23Hz.
Aloha,
Poinz |
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| panomaniac |
Hey Poinz! Good to hear from ya. Howzit?
You'll have to come over sometime and listen to my OB "Lounge Lizard" beasts. Not as refined as your Fostex, but, um, bigger....
Bring one of your nice tube amps, I'd love to hear it. Bet it could really light up the Lizards.
| quote: | | I would not neglect the Dayton IB385 |
Right. I've been told it makes a good OB woofer. Needs plenty power, tho. |
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| Poindexter |
Mardis; datchoo?
How you stay, cuz? Top shape?
Aloha,
Poinz |
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| reins |
What's about Lambda Dipole? Does John Janowitz still produce them?
His web-site seems out of date :(
http://aespeakers.com/
Stephan |
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| OTMOPO3OK |
Stephan i have one Lambda 12 with Shorting rings as a HT sub but i believe John stopped selling 15IBs a year ago.
panomaniac, I'm more and more interested in Selenium15s since you say they sound so good, but still a little concerned with 3mm Xmax. I'm not worrying about bottoming out it's just with this little Xmax driver just produces less bass energy, it's still there just scaled down. You know what i mean? Notice you yourself mention that you'd like more energy by using two. So that is my point. Unless of course you have a big room and you really need 2 drivers to feel it, then you are absolutely right. I'm not arguing just trying to absorb as much info from your discriptions as possible.
Poindexter, Dayton IB385 is a great driver for it's purpose (IB would be one of them) but it's just not good for crossing over 150-200Hz since it abruptly falls after 700Hz. Look at the SPL graph on PE site.
tinitus, you are absolutely right about Fs=20Hz driver rolling off slower than 35Hz. I'd want a driver with as low Fs as possible.
My room simply physically won't hold 18"s since i have 2 more front speakers: huge B200 winged baffle, Bob Brine's FE167E MLTL, and a huge "refrigerator-sized MLTL sub of my own design". Now ALL THIS has too fit to accommodate center channel and 108" projector screen in between. I barely have space to sleep now as it is, lol. :):):) :bawling:
DeonC, very nice driver. 12" is a little small and Fs=18 seems almost unreal for $45 provokes thoughts that it was designed with sub application in mind and won't reach too high into mid-bass region. Maybe i'm being too cautious.
I'd like to thank everyone for their input,
I thought the decision is going to be easier but it's getting harder to choose! lol
:clown: |
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| OTMOPO3OK |
Thank you Cal Weldon,
Even though i decided to get Augies it would be a crime not try Alpha15s for 45$ both. I'm very grateful for the search and links you provided.:D :D :D |
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| Cal Weldon |
| You're welcome. Good luck with the project. Keep us posted. |
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| Phergus_25 |
I was looking at all the discussion going on here and it got me thinking about a IB sub setup to go along with my A126 horns. I think I am getting down to around 50 hz with good force, so if I could use the horns natural roll off and then back them up with the sub that would be cool.
What of the above mentioned sub setus would be good for me? I am looking for cheaper the better.
-greg |
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| holdent |
| quote: | | but still a little concerned with 3mm Xmax |
Zaph talks about Xmax here http://www.zaphaudio.com/lowxmax.html and comes out against high Xmax woofers for a number of reasons. He concludes with "My advice to all in factoring Xmax of a woofer into a purchase decision is to pick the woofer with the lowest Xmax that can sustain the peaks of your preferred music listening level. If you can't reach that level with one woofer of reasonable Xmax, consider using two or more."
------
BTW I decided that the Augies were a little too rich for my blood and bought a pair of Alpha 15As and have been very happy. In the application I'm using them they've been excellent. I have not experienced any Xmax issues even at very high volume levels.
The Alphas are paired with Hawthorne Silver Iris drivers and rolled off at roughly 180 Hz using a 1st order slope (the Iris' are run fullrange). Since the Alphas only augment the bass of the Iris' everything can stay passive. Using Augies or the Dayton IB385s requires an additional plate amp with bass boast adding to the cost. |
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| Ang |
| please do let us know how you find the alpha's performance - I'm in a similar situation and more review's are better... |
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| OTMOPO3OK |
After all the contemplation I got Augies and never regret it. I can't really compare it to the Alphas or lesser drivers since i never went for them but two Augies in my medium sized room provide all the bass i ever need. I disconnected the sub from the system cos it was too boomy and i just run Augies now, even for movies, YES even for movies.
Thanks to everyone and good luck in your driver search.:smash: |
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| chops |
I noticed a few posts here about the Pyle PPA15 drivers and just wanted to say a few things...
Granted, Pyle drivers are a bit on the "cheap" side, but the PPA15 is really well built. It has a nice heavy magnet, vented pole, pulp cone and a solid stamped chassis.
And believe it or not, even with that cheesy logo on the inverted dust cap, these drivers don't sound half-bad up to 600Hz or so. I'm still using one of these drivers for part of my center channel combined with an Altec 511B/902-8T and it does a pretty decent job. The only thing is that it's output nowhere matches the Altec horn, and even after dropping the output of the Altec considerably, it's still a few dB too loud over the Pyle.
And as for dipole use, these PPA15 drivers were excellent in my H-frame dipoles. To this day, those were still the best sounding subs I have ever heard. The tightness, quickness and extention of the bass was just "real" and very natural. I was able to get usable output down to 16-18Hz, but pretty much nothing after that.
If I were to do it again, I would still go with Pyle PPA15's. The specs of the Pyle just seem nearly perfect for an OB design, which is exactly why I went with them. Even Mr Linkwitz agreed with me on these drivers.
The Eminence Alpha-15A driver's Fs is a little higher than I like at 41Hz, and the small VC and magnet just seem too weak to provide good control over the bass. I could be totally wrong on that though. Only if its Fs was a little lower and its motor structure was beefier...
If I had to go with another driver, my next choice would be the Selenium 15PW3-SLF driver. Yes, the Fs is back up higher, but at 37Hz. The rest of the specs are somewhat similar to the Pyle. One of the other good things about the Selenium is that its SPL is 98dB, which is much better than the Pyle's 90dB. Having that extra 8dB there might possibly help on the low end extention.
Anyway, just my 2 cents.
BTW, I still have all four of those Pyle PPA15's sitting here. I plan on building a pair of small W-frame subs out of them for my bedroom system! :devilr: |
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| Ang |
| chops - wrt your pyle woofers - do you have them playing down to 18Hz and up to 600Hz in and OB or are you talking about two separate setups? Thanks. |
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| chops |
| quote: | Originally posted by Ang
chops - wrt your pyle woofers - do you have them playing down to 18Hz and up to 600Hz in and OB or are you talking about two separate setups? Thanks. |
Yes, two different setups.
When I was using them as dipoles, they were crossing over at 125Hz IIRC via an Audio Control Richter Scale Series II.
The Richter Scale had a 5-band 1/3 octave EQ built into it, and I only used it to reduce the levels a bit from 90Hz up. I did not use it to boost bass output at all. I didn't need to. In fact, the fact that I kept stating that I was getting good output down to 16Hz with these dipole subs always drew a lot of scepticism and doubt. But if they're weren't willing to try it out for themselves, then so be it... My gain, their loss so to speak. ;)
**************
Now I'm still using one PPA15 in my center channel, which is a 4.23cf sealed enclosure (my old sub enclosure). The xover point is at 600Hz, give or take a few Hz. Since it is a center channel and I have a very good DIY subwoofer for the LFE information, I have all of my loudspeakers crossed over at 80Hz via my Pioneer Elite reciever.
I've tried running the center channel fullrange before, and eventhough it sounded good throughout the lower midrange, it just didn't have any reall bass extention due to the much smaller than optimal enclosure that it's in.
All in all though, I still say these Pyle drivers are pretty darn good for the money, especially if you want great results in an OB design on the cheap!
Just an FYI, I plan on upgrading both my mains and center channel with dual Usher HM15 drivers in the near future. I already have four of the 6 drivers needed and eight of the ten 4" flare ports for the project. I just need to get to designing and building the things. |
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| Ang |
| chops - thanks for the detailed explanation - helps a lot |
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| holdent |
| quote: | | The Eminence Alpha-15A driver's Fs is a little higher than I like at 41Hz, and the small VC and magnet just seem too weak to provide good control over the bass. I could be totally wrong on that though. Only if its Fs was a little lower and its motor structure was beefier... |
I, like Chops, also wish the Alpha 15s had a lower Fs etc. but still think they are a great choice for the cost.
Driver design is a series of trade offs. One of the trade offs with the Alpha 15 results in a higher Qts. The higher Qts allows the user to have an acoustic rather than electronic solution to bass drop off in OBs. Drivers with lower Qts' need some kind of electronic bass boast at lower frequencies. This virtually ensures that you'll have to use an active crossover and seperate amp (like a sub plate amp). The Alpha 15A is also relatively sensitive at 94 dB. Two together will be 97 dB. This means they won't have to be driven hard to acheive reasonable (loud!) sound levels and will have lower distortion levels at the same volume. If you're looking for deeper bass with a greater "punch" I'd argue that you'd have use a conventional subwoofer instead.
I read a lot of posts with concerns about "bass control" and smaller magnet drivers. I believe this refers the the driver's transient response and concerns about "one note bass" or "boom". I do not have these issues with the Alphas but have heard them with other high Qts drivers (small magnets) used in inappropriate situations (such as when installed in a bass reflex cab). Similarly I have heard horrific (nonexistant) bass from low Qts drivers (large powerful magnets) put in sealed or bass reflex cabs. Of course the room and cab location play a huge part in poor bass.
I don't doubt that there are many better drivers out there (like the Hawthorne Augie), but you can generally buy two or more Alpha's for every one of these and still have to get a plate amp (or equivalent). |
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| chops |
| quote: | Originally posted by holdent
I, like Chops, also wish the Alpha 15s had a lower Fs etc. but still think they are a great choice for the cost.
Driver design is a series of trade offs. One of the trade offs with the Alpha 15 results in a higher Qts. The higher Qts allows the user to have an acoustic rather than electronic solution to bass drop off in OBs. Drivers with lower Qts' need some kind of electronic bass boast at lower frequencies. This virtually ensures that you'll have to use an active crossover and seperate amp (like a sub plate amp). The Alpha 15A is also relatively sensitive at 94 dB. Two together will be 97 dB. This means they won't have to be driven hard to acheive reasonable (loud!) sound levels and will have lower distortion levels at the same volume. If you're looking for deeper bass with a greater "punch" I'd argue that you'd have use a conventional subwoofer instead.
I read a lot of posts with concerns about "bass control" and smaller magnet drivers. I believe this refers the the driver's transient response and concerns about "one note bass" or "boom". I do not have these issues with the Alphas but have heard them with other high Qts drivers (small magnets) used in inappropriate situations (such as when installed in a bass reflex cab). Similarly I have heard horrific (nonexistant) bass from low Qts drivers (large powerful magnets) put in sealed or bass reflex cabs. Of course the room and cab location play a huge part in poor bass.
I don't doubt that there are many better drivers out there (like the Hawthorne Augie), but you can generally buy two or more Alpha's for every one of these and still have to get a plate amp (or equivalent). |
Don't get me wrong, I like the Alpha-15A's a lot. And with them being on an OB, the motor only needs to cope with the cone's movement. It doesn't have to try and fight a "spring" of trapped air like in a typical sealed or ported enclosure. So with that in mind, the smaller VC and magnet probably is enough to privide decent cone control. Which is why I'm sure some say the Alpha has a smooth, warm sound to it.
Honestly, the ONLY thing that would keep me looking for another suitable driver would be the Alpha's Fs of 41Hz. Even with a high Qts of 1.26, I just don't know if these would be capable of even reaching down to 25-30Hz. At least with the PPA15's, their Fs is 27Hz, so they have the ability to reach down to 16-20Hz with very little to no EQ at all (depending on the baffle size of course).
Another option of course could be moving up to an 18" driver. Most 18's have an Fs of around 25-30Hz or so, most are pretty efficiecnt at 94dB+, and some even have a somewhat high Qts around 0.5 or so. The only drawback is that they can get pretty pricey really quick, but not always...
Here's one for example, the Goldwood GW-1858. It is rated at 94dB, Fs of 30Hz, Qts of 1.07 and an Xmax of 3.36. Being that it's a fairly efficient driver and you'd be using two per channel, that's at least 97dB, and since they would be sharing the load, the low-ish Xmax probably wouldn't be an issue. |
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| chops |
| quote: | Originally posted by Ang
chops - thanks for the detailed explanation - helps a lot |
No problem. You're welcome! ;) |
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| mashaffer |
I was considering the Pyle for IB use but was hesitating since the gurus say you need much more xmax and really expensive drivers to do IB. Given my experience with cheapo OB drivers and your comments here chops, I am begining to think that 2 to 4 PPA15 might do just fine in my 14x14 room.
mike |
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| chops |
| Well IB is definately different from OB, so I'm not too sure if the Pyles would be good for IB or not. Since you're only getting sound from one side of the driver with IB, you might need considerably more Xmax. I don't know for sure though, and I don't even know if that has anything to do with anything. |
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| Cal Weldon |
| quote: | Originally posted by chops
I plan on building a pair of small W-frame subs out of them for my bedroom system! :devilr: |
You're a wild man. |
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| chops |
| quote: | Originally posted by Cal Weldon
You're a wild man. |
Is that sarcasm I detect there? And if so, why?
If not, then thanks. LOL |
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| holdent |
| quote: | | the ONLY thing that would keep me looking for another suitable driver would be the Alpha's Fs of 41Hz. Even with a high Qts of 1.26, I just don't know if these would be capable of even reaching down to 25-30Hz. |
Chops noted what I think is the only big problem with the Alpha 15As; the higher Fs. Even modeling it with wide 36" baffles they drop at least 16 to 20 dB from 40 Hz down to 20 Hz (depending on distance to the back wall). I have them in baffles that are 19.5 x 35" wide but haven't tried measuring them outdoors. The in-room response measurements are complicated by by room nodes but seems to mirror the modeled response.
[Incidently MJ King in his Project 7 measured the Fs for the Alpha 15A to be a little bit lower than the Eminence published spec at 38.9 Hz and the Qts came out to 1.19.]
The Pyle Pro PPA15 looks to be a very good OB driver. It's cheaper than the Alpha but its about 5 dB less sensitive at 40 Hz. Even though it has double the advertised Xmax of an Alpha 15A at 6 mm, they will both exceed their Xmax at low bass frequencies at levels around 100 dB. However, due to its lower Fs, the PPA15 response doesn't rapidly drop off until lower than 30 Hz.
Unfortunately I haven't been able to find a site that provides all the TS parameters needed to model the PPA15. But with short look at it, it may be a better choice than the Alpha 15A. |
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| Ang |
Based on the various emerald physics prototypes, it does seem possible to go flat to 20Hz with alphas. Then again, there's more than one and these are active/eq'd.
http://www.emeraldphysics.com/ |
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| tinitus |
| Flat to 20hz with Alpha15A ? with room gain and all you might do it at low level, BUT at higher level you will have to consider the relative short Xmax - but as you say, with multiple woofers its a different matter, on the other hand I dont think its recommendable to force a high Q driver that low |
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| AJinFLA |
Well, xbaffle sims don't remotely back up any claims being made here. John K's excellent article about dipole behavior below the room fundamental doesn't supports any of these claims.
I wonder why it is, that there are never any measurements to back up the internet claims made about these cheap pro woofers, etc.?
Perhaps all that is needed for (dipole) output to 20hz and below is a computer keyboard and an internet connection?
cheers,
AJ |
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| holdent |
I agree with Tinitus. The other issue with pushing an Alpha 15A that low would be the high levels of distortion at frequencies below Fs at even moderate sound levels.
I looked at the Emerld Physics website but couldn't find mention of what drivers they were using. Do they note this anywhere? |
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| chops |
| quote: | Originally posted by AJinFLA
Well, xbaffle sims don't remotely back up any claims being made here. John K's excellent article about dipole behavior below the room fundamental doesn't supports any of these claims.
I wonder why it is, that there are never any measurements to back up the internet claims made about these cheap pro woofers, etc.?
Perhaps all that is needed for (dipole) output to 20hz and below is a computer keyboard and an internet connection?
cheers,
AJ |
Gee, why do I have the distinct feeling that you're referring to me? Maybe because you pulled the same type of thing with me before in my own thread and other related threads? I would think you would get bored of doing this everytime, especially over what, 3+ years now?!
You fail to remember... I didn't build my dipoles to be small and compact like everyone else does. Nor did I use drivers with the wrong T/S parameters for dipole use just so I could have a large Xmax. No, not at all. Mine stood 4' tall, were 2' square and used drivers who's T/S parameters were darn near perfect for dipole use. With the amount of baffle I had along with the low Fs of the "cheap pro woofers" as you so put it, is precisely why they were able to go so low without any EQ help.
But you know what, I'm not going to sit here and get ticked off and argue with you. Some people are just too stinkin' pig-headed and closed-minded to accept anything other than measurements and what they "think" is right.
For some people to pretend that they are smart, all they need is a "computer keyboard and an internet connection", right? LOL
You know, instead of trying to pick fights all the time, why don't you just try building the exact same dipoles I had? It wouldn't cost anymore than about $150 for the drivers and wood and would finally prove to you what they are actually capable of. That would be a small price to pay to finally shut you up for a while.
At any rate, have a nice day. :D |
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| AJinFLA |
| quote: | Originally posted by chops
Gee, why do I have the distinct feeling that you're referring to me? |
Paranoia? Self doubt? I would consult with your psychiatrist. I concede to their expertise in these areas.
| quote: | Originally posted by chops
You fail to remember... I didn't build my dipoles to be small and compact like everyone else does.....No, not at all. Mine stood 4' tall, were 2' square |
| quote: | Originally posted by chops
At last!!!! I just got finished building and installing my new dipoles, and must say that I am very, very impressed...
Oh yeah, did I mention that they are HUGE?! (24" D, 24" W, 36" H)
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Perhaps, like many tales, they have "grown" taller with age?
| quote: | Originally posted by chops
is precisely why they were able to go so low without any EQ help. |
If you claim so.
| quote: | Originally posted by chops
Well I tried that RTA software and couldn't get anything to show up. It worked twice, then after that, everything kept coming up blank. No numbers, no graphs, nothing. The heck with it. I know it sounds good and that's all that matters to me. |
That's not a good indication that 16hz was measured. Or anything else.
| quote: | Originally posted by chops
why don't you just try building the exact same dipoles I had? It wouldn't cost anymore than about $150 for the drivers and wood and would finally prove to you what they are actually capable of. |
It would be much cheaper and less time consuming for me, if you were to get help, get the measurement software you own working and post some measurements on your image hosting site. No?
Then we could all see that 16hz response from the no eq 26hz Fs dipole drivers eh. As you claim.
cheers,
AJ |
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| chops |
| quote: | Originally posted by AJinFLA
Paranoia? Self doubt? I would consult with your psychiatrist. I concede to their expertise in these areas.
Perhaps, like many tales, they have "grown" taller with age?
If you claim so.
That's not a good indication that 16hz was measured. Or anything else.
It would be much cheaper and less time consuming for me, if you were to get help, get the measurement software you own working and post some measurements on your image hosting site. No?
Then we could all see that 16hz response from the no eq 26hz Fs dipole drivers eh. As you claim.
cheers,
AJ |
No, no paranoia or self doubt. I just know how you are. And so what, I forgot exactly how tall they were. Wow. But I was right, they WERE 24" square. LOL
And as for the TrueRTA software, that was on my old laptop, and for whatever reason, it didn't want to work right. Maybe it was some kind of conflict with the onboard soundcard. Who knows, who cares. The thing is, it DID work on my server PC just fine once I got the cabling, mic preamp and everything run into the other room, and whether you believe it or not, that 16Hz was the measured results. I never posted it because the thread had pretty much died at that point and I was sick of dealing with you on it every single time. Also one of the reasons I left this site for nearly a year.
"It would be much cheaper and less time consuming for me".. Yeah, like I care about what's easier for you. LOL
I have no reason what so ever to lie, knowing darn well anyone on this board could easily go out, buy these same drivers, build the same baffles and come up with very similar results as room modes would have very little impact on the final results. Anyone is more than welcome to prove me wrong, and not be out a lot of money in the process. I even spoke to Seigfried Linkwitz on a number of occations about these dipoles and even he was quite positive about them.
Much like most other "normal" people, I don't get tied up in software and mathematical predictions. If you want to find out if something is going to work, you just have to build the darn thing and see what happens, which is exactly what I did. You on the other hand just get all moody because my "claims" don't jive with your calculations. Tough, too bad.
If you don't like it, then prove me wrong and build those dipoles. Unless you're affraid to because you'll find out the same results I got and realize that you've been wrong all these years. But knowing you, you'd probably alter the results to try and prove me wrong anyway.
Looks like you've got some work to do, so get crackin'! LOL ;) |
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| mashaffer |
Chops, I may be all wet but my thinking was that in IB there would be no cancellation. My theory is that with cancellation more cone movement would be needed for the same output so in theory it would seem that IB would need less excursion for the same output. It is possible of course that the reflected backwave reinforcement may be a factor.
mike |
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| chops |
| quote: | Originally posted by mashaffer
Chops, I may be all wet but my thinking was that in IB there would be no cancellation. My theory is that with cancellation more cone movement would be needed for the same output so in theory it would seem that IB would need less excursion for the same output. It is possible of course that the reflected backwave reinforcement may be a factor.
mike |
Hey Mike,
I too am kinda "wet" when it comes to IB's. What I was thinking though is that because there is nearly no air resistance with IB (meaning a spring of air like a small sealed enclosure would have), the controlled motion of the cone is entirely up to the motor and suspension. So when the driver approaches and/or exceeds its Fs, it could start to "flop" out of control similar to a driver going below the tuning point of a ported enclosure.
Of course, I am only guessing at all of this as I haven't really done any research on IB's, so don't go by everything I say until someone with some real knowledge can shed some light on the subject.
Then again, the same is true for OB's as well, but I never had that problem with my dipole subs because the Audio Control Richter Scale xover I was using had a subsonic filter built into it @ 20Hz, which would explain why I never had that problem. |
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| BWRX |
| Guys, chill out and keep the posts on topic. |
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| chops |
| quote: | Originally posted by BWRX
Guys, chill out and keep the posts on topic. |
Thanks BWRX and sorry. I've been trying to keep things on topic. ;) |
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| AJinFLA |
| quote: | Originally posted by holdent
Unfortunately I haven't been able to find a site that provides all the TS parameters needed to model the PPA15. But with short look at it, it may be a better choice than the Alpha 15A. |
Here you go
Re is probably slightly less, but will have a minimal effect on the overall response.
cheers,
AJ |
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| Ang |
One thing I'm wondering is the following:
Since high Qts is at least helpful for getting bass out of OB designs without EQ, in comparing drivers lines, the one with a larger magnet (more expensive) basically always has a lower qts, so is that bass you get from the high qts designs really accurate bass?
I'm thinking of
goldwood 15", qts .63, $45
http://www.partsexpress.com/pe/show...tnumber=290-345
vs
goldwood 15", qts 1.95, $29
http://www.partsexpress.com/pe/show...tnumber=290-384
for instance, but this seems to hold for any manufacturer. |
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| Taterworks |
| quote: | Originally posted by OTMOPO3OK
Thanks everyone for your input,
Ciares seem fishy and even more expensive than Augie. |
Fishy? Better not tell Meyer Sound, who used Ciare drivers in their early models, when they were making their name.
http://www.meyersound.com/ |
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| chops |
| quote: | Originally posted by Ang
One thing I'm wondering is the following:
Since high Qts is at least helpful for getting bass out of OB designs without EQ, in comparing drivers lines, the one with a larger magnet (more expensive) basically always has a lower qts, so is that bass you get from the high qts designs really accurate bass?
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This would be true if you were installing the drivers in an enclosure. It's also somewhat true I suppose for OB, but nowhere near as bad. With an OB, there's no resistance on the driver. The only thing the motor has to do is take care of the cone movement. It doesn't have to fight with the air pressure inside a cabinet.
Think of it like flapping your arms in the air vs flapping them under water. The water creates a lot more resistance and you can't move your arms as fast as you can in air. |
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| holdent |
Ang - I think you got the Goldwood woofers mixed up. This one http://www.partsexpress.com/pe/show...tnumber=290-345 is the GW-215 at $29.00 with a Qts of 1.95. I have got two of these which I compared to the Alpha 15As. I was attracted to them for the reason you noted - the very high Qts and offered a way to get deeper bass without need for any EQ.
Unfortunately the GW-215s have a lower sensitivity and low Xmax and consequentlyof steam long at high volume levels. At these levels the bass sounded bloated and was clearly distorted. Because the GW-215s are so inexpensive I also tried 2 in a baffle compared to 1 Alpha in the same size baffle (24 x 40"). The single Alpha was still far better. |
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