Graham Maynard said:
Never said anything about losing the wife.
Think way back when you very first met your wife. Did you stand your ground on certain things? I'm sure SHE did, and probably still does, and likely gets away with it too. But if YOU haven't and you've been married for many years, I suppose it's too late now. She'd likely raise hell. All of you guys on this forum complaining about this WAF obviously made that mistake too long ago. Kinda pathetic IMO. And no, I'm not controlling, very far from it.. most consider me the exact opposite of controlling. Nor do I 'wear the pants' in the relationship, but neither does she. We both do. As a result, we both tend to get away with the things that mean the most to us. Works out fine. I don't see why this is so difficult for most people?
Besides, she enjoys using my 'stuff' too. Maybe not as much as I do, but she does use it every day.
When I first met her, I think it was obvious that negative words/actions towards me and this hobby didn't stand a chance of having the least bit of effect. It was here before her. She chose to become a part of it when she decided to share her life with me.
Perhaps for most of you there really is a required choice to be made between WAF or no wife. But if that's really the case, that's sad.
Matter of fact.. if my fiance had never had any of her own interests with similar obsession, I'd be awfully worried. Not just about her, but about myself.. as my deep interest in this hobby would seem extremely abnormal, to say the least. But it doesn't, because she does what she does, and I do what I do.
Wouldn't your wife rather have YOU and your hobbies and interests than no you at all? I guess not. Is that normal? I've never thought so. Sure seems like it around here though..
I suppose this has gotten way OT. My apologies.
Actually I don't think it's off thread, if getting the best sound you can in the evironment you have is the only thing we have on our minds, we've got too little to think about.
Music and music reproduction is very important to me, slightly less so to my wife.
There are far more important things ; our health, family, relationships; the environment! World Peace even!!!
With myself it's a passion not an obsession and my beloved puts up with it because it's part of who I am, and I'm glad she questions the need for even more speakers sometimes; otherwise I'd have no room for the books, silverware and the fancy glassware and crockery we got as a wedding present
Music and music reproduction is very important to me, slightly less so to my wife.
There are far more important things ; our health, family, relationships; the environment! World Peace even!!!
With myself it's a passion not an obsession and my beloved puts up with it because it's part of who I am, and I'm glad she questions the need for even more speakers sometimes; otherwise I'd have no room for the books, silverware and the fancy glassware and crockery we got as a wedding present
panomaniac said:
Sure. You said:
panomaniac said:
I've found that for whatever reason, woofers on OB seem to act much differently as far as Fs and roll-off is concerned. As Fs is lowered, Qts has to increase a certain amount to obtain a similar roll-off as would be seen if it had a higher Fs. Shortly before I ever found out about the simple XLBaffle.xls quite a while back, I had actually purchased a cheapo 15" car woofer.. just one of them for a cheap experiment. I put it on a decent size 3.5 ft tall by 2 ft wide baffle, mounted at the bottom center near the floor. While it had an Fs of around 22 Hz and a Qts of 1.8 IIRC, there was a very shallow but big drop in SPL from about 150 Hz to Fs, around 12dB IIRC, and as much as 16-18dB in certain parts of the room.
Since then, after doing lots of reading and researching (as most do around here), I stumbled upon XLBaffle some time ago, and realized that my previous real-world results pretty much mimicked the simple simulations in that spreadsheet. After playing around with that for a while, reading up on OB's, and reading about MJK's use of the Alpha 15, I bought one to try out. Just as XLBaffle predicted and as MJK's article showed, the Alpha 15's higher Fs of 40+ Hz (versus the previous 22 Hz for the car woofer I had played with in the past), seemed to cause a much flatter response all the way down to Fs, but with a faster roll-off afterwards. Eventhough the cheap no name car woofer had a much lower Fs, I had to crank the hell out of it to get any output even at 30+ Hz, at which point it was reaching Xmax.. even though that woofer had a similarly high Qts. XLBaffle clearly shows this as well. As for why it works this way, I really have no idea. But I now know for certain that this seems to be the case regardless when dealing with woofers on flat OB's.
So, on an OB, a lower Fs is obviously NOT better. There's some decisions and compromising that has to be done. Not only that, but the lower Fs drivers on OB seem to want to flap out of control anyway IME. Once again, extremely low frequencies on average size OB's at decent output levels isn't sane.
Anyway, that's why the Carver Amazing woofers had such a high Qts, and the reason why they were having issues trying to come up with solutions. They were trying to get very low frequencies out of an OB.
But yeah.. low frequency roll off of the woofer not only seems to be highly dependent on baffle size and Qts, but it definitely depends on Fs as well.
BHTX said:
Ah yes, now I see what you mean. That's what I've seen too. I find a big drop off under Fs, even is the drop above is gentle. XLbaffle seems to confirm this. The higher Fs seem almost like a peg to hang the bottom of the FR line on.
Thanks for the very informative post.
SY said:
Oh.
I thought you were going to say "wine."
panomaniac said:
I believe the reason for the higher Fs working better is because of baffle dimensions. Think about it.. the woofer is wanting to vibrate and stretch that frequency response all the way down to 20 Hz or whatever, but the baffle is the limiting factor. It's not big enough to give support anywhere near that far down, so you end up with cancellation, which causes the shallow roll-off when using low Fs woofers on an OB. With a woofer that resonates an octave higher than that (say 40Hz, for instance).. it's not going to give much output below that point anyway, and will want to start rolling-off regardless.. and the high Q at resonance is helping to push things up at and above Fs, which flattens out the response above that point quite a bit. That also explains the faster roll-off when using a driver with a higher resonance and higher Qts. The Fs, Qts, and baffle dimensions are all working together to give the end result. So, with that said, you can't simply say "#.# Qts works best on OB without EQ", or "A baffle that's ## inches by ## inches works best for...", or whatever. There's really no way to have the slightest clue what the response will turn out to be like without having at least these three variables.
Hi GM,
Going back to the low Qms mentioned above - four of these 10"ers in ser/par would have reasonable LF output ;-
http://www.visaton.com/en/chassis_zubehoer/tiefton/ws25e_8.html
Shouldn't break the bank either.
Cheers ..... Graham.
Going back to the low Qms mentioned above - four of these 10"ers in ser/par would have reasonable LF output ;-
http://www.visaton.com/en/chassis_zubehoer/tiefton/ws25e_8.html
Shouldn't break the bank either.
Cheers ..... Graham.
Attachments
Yes, but not enough to go low. With 3+ Qts drivers, the Carvers are still ~60" H x 1" D x 48" W tapering to 36" at the top.
Yeah, I'm not such a big fan of OB to want to go all that low with them. Magnetar's latest creation seems a reasonable solution to me if the budget is large enough, otherwise a higher OB cut-off is required to keep driver count down, making a ~80 Hz XO point seem a good trade-off between Qts, baffle size and driver count IMO.
This is pure speculation on my part though since during my building years I was more interested in acoustic efficiency/directivity and I didn't have available to me the relatively inexpensive, high Xmax drivers and electronics required to go low, so did very little experimenting, concluding at the time that it was only practical down to ~500 Hz to keep distortion, parts count/cost low.
GM
Yeah, I'm not such a big fan of OB to want to go all that low with them. Magnetar's latest creation seems a reasonable solution to me if the budget is large enough, otherwise a higher OB cut-off is required to keep driver count down, making a ~80 Hz XO point seem a good trade-off between Qts, baffle size and driver count IMO.
This is pure speculation on my part though since during my building years I was more interested in acoustic efficiency/directivity and I didn't have available to me the relatively inexpensive, high Xmax drivers and electronics required to go low, so did very little experimenting, concluding at the time that it was only practical down to ~500 Hz to keep distortion, parts count/cost low.
GM
kEEP IT COMING
I've just been offered a pair of 15inch Adire subs at a reasonable price, I'm going to buy them (Thanx otto 88 ) I have a quad of cheaper but reasonably efficient 10inch woofers that will give a sealed box response down to around 60Hz.
I have to stop thinking about this project and start building, if it;s not right when I finish I know it will be netter than anything I can afford to buy.
Having read and absorbed most of the advice;; I don't ( in this room in this house) need concert levels; peaks of 120 will be a little distorted and we will live with that.
So 15 sub, 4 * 10inch mid-basscross around 350/500 to some small Vifa mids (the M11MH 08 * 4)and whatever tweeter I have that will fit into the box I think I'll use the Vifa D 26 maybe not the best but it's sitting on the shelf
At this stage I'm still thinking of using the electronic cross-over for sub and bass and simple L/R on mids to tweeter.
I've just been offered a pair of 15inch Adire subs at a reasonable price, I'm going to buy them (Thanx otto 88 ) I have a quad of cheaper but reasonably efficient 10inch woofers that will give a sealed box response down to around 60Hz.
I have to stop thinking about this project and start building, if it;s not right when I finish I know it will be netter than anything I can afford to buy.
Having read and absorbed most of the advice;; I don't ( in this room in this house) need concert levels; peaks of 120 will be a little distorted and we will live with that.
So 15 sub, 4 * 10inch mid-basscross around 350/500 to some small Vifa mids (the M11MH 08 * 4)and whatever tweeter I have that will fit into the box I think I'll use the Vifa D 26 maybe not the best but it's sitting on the shelf
At this stage I'm still thinking of using the electronic cross-over for sub and bass and simple L/R on mids to tweeter.
I,m having fun today playing with different amplifier combinations, currently using a small Alessis as a mid-top amp, the RA - 100; it's very bright and forward compared to the Rotel ( and amps don't make a difference??? HA!! )
I didn't build the speakers I'm using to play with, just an old pair of Sansui vented 2-ways based on a copy of the Phillips 7inch bass-mid driver (of course new crossover ) no SPL so the tweeter is padded down 8dB, must say the box is well constucted but it's amazing what a few grams of polyfll can do.
These are in the computer room and quite loud enough in a small room, good bedroom speakers and they were very cheap, using a Jaycar kit-amp the "Playmaster PRO -3" driving the Cerwin Vega 12's which I confess are still in the small sealed boxes.
I do like Mosfet amps for bass.
But in the bigger room these would not be this loud and I'd not be sitting only a metre away from the boxes.
I didn't build the speakers I'm using to play with, just an old pair of Sansui vented 2-ways based on a copy of the Phillips 7inch bass-mid driver (of course new crossover ) no SPL so the tweeter is padded down 8dB, must say the box is well constucted but it's amazing what a few grams of polyfll can do.
These are in the computer room and quite loud enough in a small room, good bedroom speakers and they were very cheap, using a Jaycar kit-amp the "Playmaster PRO -3" driving the Cerwin Vega 12's which I confess are still in the small sealed boxes.
I do like Mosfet amps for bass.
But in the bigger room these would not be this loud and I'd not be sitting only a metre away from the boxes.
GM said:
any link to magnetar?
even with a 80Hz cut off driver count is still a 3-4 way.
a sub below 80Hz
a OB midbass from 80Hz to the midrange
a OB midrange like a Supravox, Visaton, etc...
and a tweeter (optional for some, essential for me)
I dont know of any driver that can go from 80Hz to say 6khz keeping the "trade-off between Qts, baffle size and driver count" that GM listed in his post. Does anyone? Visaton B200? Supravox 215? Veravox 7x?
I don't think I have the experience or funds of Magnetar ( or the brains either ) so I am going to go with what I know.
When all the bills are paid (( Cecile has to fly to NewYork in September for birth of first grandchild ___ Damn having family scattered all over the globe can be expenxsive)) I may have the funds to experiment further with Bigger/Better drivers, and my open baffle experiment is working out well but bass and open baffles and high SPL don't come cheap, so for the lower octaves I personally will stick with sealed boxes.
For those aussies who have a liking for open backed woofers the cheap paper driver from Jaycar is on sale at around $20.
Qts of 1.46/Fs of 32 and can only handle about a quarter of the rated power , i:e only about 12 watts as only 4mm X-max, but you could probably fit a half dozen on a 1/2sheet of chipboard and room for a couple of 10inch mids and a tweeter.
Now that is a cheap speaker
When all the bills are paid (( Cecile has to fly to NewYork in September for birth of first grandchild ___ Damn having family scattered all over the globe can be expenxsive)) I may have the funds to experiment further with Bigger/Better drivers, and my open baffle experiment is working out well but bass and open baffles and high SPL don't come cheap, so for the lower octaves I personally will stick with sealed boxes.
For those aussies who have a liking for open backed woofers the cheap paper driver from Jaycar is on sale at around $20.
Qts of 1.46/Fs of 32 and can only handle about a quarter of the rated power , i:e only about 12 watts as only 4mm X-max, but you could probably fit a half dozen on a 1/2sheet of chipboard and room for a couple of 10inch mids and a tweeter.
Now that is a cheap speaker
Regarding the Alpha15 I can show a recent measurement of mine of this speakerunit fullrange in my passive 'Volks-OB' taken in the livingroom. It confirms BHTX claims fully:
In the 'Volks-OB' it sits 10" above floor in a 'topless-U', 24" x 16" (60 x 40 cm) main baffle with 24" x 12" (60 x 30 cm) wings at 90 degrees to the baffle.
/Erling
An externally hosted image should be here but it was not working when we last tested it.
In the 'Volks-OB' it sits 10" above floor in a 'topless-U', 24" x 16" (60 x 40 cm) main baffle with 24" x 12" (60 x 30 cm) wings at 90 degrees to the baffle.
/Erling
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