| Bluto |
Wasn't sure if this belonged here or not. FR is primary attribute but OB is subject.
In last couple days I've run into several designs that people have DIYed that I happen to own same drivers for. I bought them simply to play with or felt they were deal enough I'd get my money back if I couldn't use them. Frankly I was surprised to see others had similiar thoughts.
XO design is something I'm going to have to learn should I continue in this hobby. All software I've seen for design is box oriented.
Is there such a thing as OB design software or if not can anyone lead me to what I should be reading?
Some of these drivers were purchased without even knowing TS and despite many still on market sellers not offering such yet others are using them even as I'd envisioned.
Thanks - Bluto |
|
|
| LineArray |
Hi,
this is a nice tool for simulating effects
of different baffle sizes and placing of drivers.
For first tries it works cheaper than cutting wood.
Concerning XO the tool makes proposals for
baffle step compensation.
http://www.tolvan.com/edge/
Note: This tool works with idealized drivers.
The drivers effects on bass response e.g.
have to be taken into account by yourself.
Here is much OB theory and practical hints too.
It is a "must read" to me ...
http://www.linkwitzlab.com/
There is an Excel Spreadsheet e.g. which is able to calculate
displacement volume needed dependent on radiated
frequency and distance of the dipole sources.
Best regards |
|
|
| Nelson Pass |
Being that open baffles are so easy to design and construct, the
crossover is by far the biggest hurdle.
OB crossovers are a lot like other crossovers. You can start with
a textbook value, and then the work begins, tweaking it, starting
over, tweaking that....
Keep in mind that a flat OB has a different character with regard
to baffle step correction and diffraction.
It can be a very rewarding activity if you have patience. Sometimes
a crossover gets nailed pretty quickly, sometimes it takes months.
Commonly a crossover that measures pretty flat still doesn't sound
right, and you have to try something else.
Life is easier if you have an active crossover and some capacity for
equalization, and is easiest if you have some measurement
equipment.
Of course the fastest way is to find an example with your drivers
that's been worked out.
What drivers and baffle are you considering? |
|
|
| Bluto |
Thanks Guys -
Some of this I'd read and forgotten it existed so I'll go back and re-read. Some of these links are new to me so will be helpful.
Nelson ... Somewhat difficult to nail it down as I'm doing a bunch of experiments including 'augmenting' FR's with different drivers such as guys running both large Eminence with Visiton B200's .
I've got some Misco J9 series 5 x 7's that have a 95db SPL. I could provide you the link if you'd want it. Right now I have 4 of them wired together and they sound great but FR is only about 75 - 12000. The closeout Onkyo tweets P.E. had wake them up pretty good. Qts not provided by them but I've spoken to them in past and they do allow you to talk to Engineers so I know I could get the stats. I'm guessing it's above .9.0 . Also playing with Pioneer A11, Sammi cast 4" FR that I'm having trouble finding numbers for, Pioneer FB11 is a mid but Qts has to be high as they integrate terrifically with other 8" and above FR's I have that do have high Qts and SPL is decent so considering a decent baffle for them , MTX/Oaktons , now defunct and will never get numbers for as well as a few I'd have to dig out of boxes as it's been awhile.
All of these experiments have me considering if buying testing equipment would be worthwhile.
As with all, I'm looking for the 'Holy Grail' and have been astounded that several dirt cheap drivers I've purchased have outperformed drivers of reputation that cost me as much as 5 times more.
I'm really enjoying FR OB and simply thinking there are likely many good 'low buck' drivers out there that may never have been intended initially for this purpose but would serve very well.
Bluto |
|
|
| Nelson Pass |
Alas, I have no experience with Visatons, so I can't help you directly,
but if you are persistent, you'll be able to get them tweaked in.
And while you're looking a low buck bargains, don't forget the
Pioneer BU20FU20. |
|
|
| Kensai |
Which is on sale at PE for $20 right now.
Kensai |
|
|
| ttan98 |
| quote: | Originally posted by Nelson Pass
Being that open baffles are so easy to design and construct, the
crossover is by far the biggest hurdle.
OB crossovers are a lot like other crossovers. You can start with
a textbook value, and then the work begins, tweaking it, starting
over, tweaking that....
Keep in mind that a flat OB has a different character with regard
to baffle step correction and diffraction.
It can be a very rewarding activity if you have patience. Sometimes
a crossover gets nailed pretty quickly, sometimes it takes months.
Commonly a crossover that measures pretty flat still doesn't sound
right, and you have to try something else.
Life is easier if you have an active crossover and some capacity for
equalization, and is easiest if you have some measurement
equipment.
Of course the fastest way is to find an example with your drivers
that's been worked out.
What drivers and baffle are you considering? |
Nelson,
I have similar experience.
That's very good advice, there is no substitute for experience. |
|
|
| Bluto |
Experience is likely the best Teacher.
Wish I hadn't have gotten out of Audio for as long as I did.
I am having some Fun but even low buck experimenting gets expensive.
What bothers me but also makes me laugh is that I see even Guys with bigger wallets are never satisfied and always looking for more.
I swear I'm gona put together a system that keeps me happy for at least a few years but I think I'm kidding myself.
I'll likely not be happy until I build something the whole County can hear without distortion with less than 20 watts of power. Then I'm gona play it until I get arrested! Buddy Holley and Bo Diddley.
I keep envisioning Noriega looking for blankets to cover his ears when they blasted him with Rock n Roll n Panama.
Bluto |
|
|
| DaveCan |
Bluto, I'd guess that the bigger wallets always looking for more, either have not taken their room into account, or just enjoy serial upgrading..
The crossover ? I would think the best bet would be to get the best active crossover one could afford, not sure why most go the passive way as I'm no speaker designer but it just makes sense to me somehow.. Dave:) |
|
|
| Nelson Pass |
| quote: | Originally posted by DaveCan
I would think the best bet would be to get the best active crossover one could afford |
Better yet, build an excellent active crossover. Not hard to do
at all. |
|
|
| DaveCan |
| Easy for you:wiz:, difficult for me :scratch1: Dave:) |
|
|
| ttan98 |
| quote: | Originally posted by Nelson Pass
Better yet, build an excellent active crossover. Not hard to do
at all. |
Nelson,
Do you refer analog over digital active x-over?
If so please briefly explain why? |
|
|
| Nelson Pass |
I like analog.
I am not a digital designer.
(actually that's not literally true. I designed a zero-instruction-set
computer and bought 20,000 Zetex ZVP3310's with which to construct
it. Now I have to buy a lot of solder.)
:cool: |
|
|
| gainphile |
Active crossover is definitely easier (and cheaper) than passive counterparts. R and Cs cost only few cents :D
Plus you can equalise the bass... important for OB :D |
|
|
| Bluto |
DaveCan -
Thanks.
I started the 'Maths' thread awhile back cause after a year of study I realized I'd never possess the abilities to design my own XO's, I simply don't have the attributes necessary. Being honest with yourself will save time as well.
That realization led me to involvement in several threads concerning active XO's and it is definitely something I'll get involved in as soon as affordibility exists. I see them as even having qualities that could help in building passives. Initially I'd only looked at them regarding equalization in an IB Sub system so reading up on them was a good thing.
The time spent studying is worth it. I'm happy that I chose to experiment with speakers 1st rather than play with the electronics end and make serious money mistakes. I had initially planned purchasing a new high end HT Receiver for movies but now plan on likely Emotiva with a processor. Perhaps a used Bryston.
Forums are invaluable.
Bluto |
|
|
| Bluto |
Gainphile -
I've ran into your blog on a couple of occasions and am impressed with what you've done.
Are there threads here that give more explanation? Many questions.
Thanks - Bluto |
|
|
| gainphile |
I think my breadboards are far to be desired... not very "audiophile" :D
When I started I asked alot of OB questions but on the "Loudspeakers" section. I think that's where most of OB discussions are happening.
Summary of those experiences is here :
http://gainphile.blogspot.com/2008/...b-speakers.html |
|
|
| Bluto |
gainphile -
Thanks - don't know why I didn't see this when I was going through your site.
Bluto |
|
|
| marec |
I do keep banging on about the Behringer ultradrive pro...
Digital crossover, great response shaping abilities, easy to use!
The cost approximates to a couple of passive low frequency crossovers built with decent coils and capacitors. you can experiment easily and quickly and get yourself to a decent sound without endless replacement of expensive passive components.
Go on! You know you should!
Rgds |
|
|
| martinv |
The great thing about active crossovers is that you can combine them like building blocks with one stage not influencing the next*. I can't think of any (then again I'm not well versed in what's available on the current kitset scene), but surely there are 'building block' active crossovers out there that you can buy and throw together without having to know the gory details.
On the other hand, I started tinkering with open baffles almost a year ago (! time flies), and decided to build my own active crossovers for a two way OB (bass+full-range driver). I actually had some Marchand 24dB/octave XM9 from a few years back (when they used polystyrene caps!) and I have used these for the lowest crossover at 200Hz. The nice thing about the Marchand is it takes a plug in resistor pack which sets the crossover point. Changing crossover point is then easy - just swap the resistor pack.
I still needed the 6dB/octave low pass to correct for the OB bass, and wanted a baffle step correction feature as well. Extra gain would be useful too, oh and a sub-sonic filter (to stop that boosted woofer flapping about needlessly), plus perhaps some buffer stages thrown in for good measure and the ability to mix and match which features are 'in circuit', as well as multiple 'taps' for multiple outputs (so the full range driver gets the baffle step correction, but not the sub-sonic filter for example). To cut a long story short, I have a PCB layout ready to go - just working on getting a couple of prototype boards made, and have all the parts here from Digikey waiting to go. I thought I would be the only person on earth who might be interested in such a PCB, but maybe others are also interested? Of course it's still a prototype, and I'll probably not need half the stuff I've included on it, but then again, for the person who doesn't know which feature they might need, maybe it has an application?
-Martin
* well, at least when some simple constraints are met, like high input impedance and low output impedance, which isn't asking too much. |
|
|
| norman bates |
There is a great sounding passive line level crossover,
better than opamps, coupling caps, let alone multiple stages of buffering and d/a, not to mention teens of electrolytic coupling caps in the signal path of active pa crossovers.
the marchard xm46
http://www.marchandelec.com/xm46.html
audioasylum.com
" "I thought the XM46 would do the trick too, that's why I bought it. Unfortunately it sucks the life out of the system"
The impedance is too low for your preamp to drive and it makes the dynamics suffer (been there, done that). "
1 board assembled (mono high or low pass) for $100.
but yea, active crossover gets you close..........
Norman |
|
|
|
