SAL Full Range Drivers

[tommydoan84]

Thank you for the pointer Vix. Definitely looking into Nelson's Slot Loaded Open Baffle. You're right about the chillout music part with one FR driver in a big OB. For critical or more demanding music, it needs serious tweaks.

I'm already looking into the active Xover starting with miniDSP 2x4. Will also look into B5 in the near future.

This OB project has opened up so many new possibilities and learning curves for me. My head is spinning a bit for a bit overwhelm info but i'm catching up fast and excited at the same time too!

Best regards,
Tom

Originally Posted by Vix

@Tom: Having just one fullrange driver in a big OB can sound sweet and very nice for easy chillot music, but won't do if you want to play something more demanding.
If I was you, I would buid something like Nelson's Slot Loaded Open Baffle, but I would use two Eminences side by side in a Slot, just like in the article, and then the Sal above them. You can experiment with passive crossovers but best is to go active. You can try to use a simple first order passive crossover, but driven by two separate amps so you can adjust relative gains. For woofers, if they are in parallel thus giving 4 ohms, you will need at least 10mH inductor in series. For the Sal, try 100uF cap in series. These are just starting points for experimentation. Otherwise, the best solution is to use B5 active crossover...

[laverda]

Originally Posted by tommydoan84

I'm already looking into the active Xover starting with miniDSP 2x4. Will also look into B5 in the near future.

Best regards,
Tom

I'm using a miniDSP 2x4 HD at present in an active 4 amp setup with my SAL and 15" bass's OBs and its very good indeed with the ability to EQ, phase and time align. It does take some 'learning' on how all the software works and how to implement each. (I have yet to master it) But with my first measure with the recommend REW software and the UMIK 1 I was amazed at the results when imported in to the DSP.

It's transformed my system into something really nice....

[Variac]

Two SALs in one panel could create all kinds of combing issues as it’s imposssible to get them close enough together to keep the high frequencies from interacting and producing nulls. A bad idea.

The problem with your bass driver setup is that many “full range” drivers don’t have much bass but are really efficient. The SAL sacrifices some efficiency to get more bass, so probably with the arrangement you tried the crossover was designed for a typical efficient full range with little bass. So your setup had way way too much of the sound coming from the bass drivers due to the efficiency difference, AND made even worse by the extra bass the SAL has. The 2 bass drivers are much more sufficient towns the higher bass, so you need to equalize them so the high bass and midrange is reduced tremendously, and the lower bass is shaped correctly.

As I’ve mentioned, I haven’t followed every post on the thread so don’t know if there are projects with the crossover settings posted but you’d be best served to exactly copy one of the project that are claimed to be successful. They are no doubt better than what you would come up with. Buying exactly the bass drivers others used and using their crossovers should still be much much cheaper than buying another set of the SALs. The miniDSP is about the only chance you have to try enough configurations.

Clearly loudspeaker design beyond just putting a full range in a baffle is much much more complicated that you (and many other people to be fair) had thought.

[Variac]

Nelson Pass has mentioned he wants to do a SAL 2way with baffles andthe beta 15” Eminence Woofer. He is also working on various new DIY analog adjustable crossovers. I suspect that when those appear he won’t be able to resist working out a SAL solution. To be safe I’d say within a year.....

[planet10]

Originally Posted by Variac

Two SALs in one panel could create all kinds of combing issues as it’s imposssible to get them close enough together to keep the high frequencies from interacting and producing nulls.

One can add a filter to minimize or eliminate the issues. I like the series option (but then am not a big OB fan), but the extra gain from parallel might be useful on an OB, filter would ned to be set to where the wrap around starts wiping out the bass.

http://www.planet10-hifi.com/downloa...ver-Wiring.pdf

dave

[Variac]

Of course, but seems pointless for him to get 2 more very expensive drivers and then still have to figure out how to use them. Glad you are going to take on this project

[planet10]

Caertinly getting a couple 15s to work with a single SAL makes a whole lot more sense as far as bass quantity goes. Some of the cheap 15s don’t keep up quality wise.

dave

[tommydoan84]

Variac,
Appreciate the inputs. The model that I'm building is not my own creation. It's almost the direct copy from PureAudioProject PureAudioProject – Open Baffle Speakers, Drivers and more.. which I already mentioned multiple occasions on my posts. It's a bit annoying when you keep repeating this. Sorry to put it out here.

Everyone has to start from somewhere. I think you do too. I might be novice in this but I'm sure there are alot of things that I'm an expert of and you would not have a clue. I'm willing to learn from people with good intention to share the knowledge.

Of course, but seems pointless for him to get 2 more very expensive drivers and then still have to figure out how to use them

I don't see why it's pointless for me to try out both drivers, if it brings back good results. Please do not underestimate someone's budget and knowledge here. I don't know what your background or who you are but I respect you, obviously, you don't know what my education and background are so at least give some respect here

Thanks
Tom

[scottjoplin]

It's not that unusual to put two wideband drivers close together. There will be comb filtering at higher frequencies that you could probably measure but I almost guarantee you won't hear it due to the influence of the room and psychoacoustics. If they are further apart and cause problems at lower frequencies it's more likely that you'll be able to hear them

[Variac]

Tom,
I’m not insulting you in my opinion. Of course you probably know more than I in many fields and probably have more money too! But it is clear that you aren’t an experienced speaker designer or builder and I have been trying to help you. I’m the one who figured out you were listening to the drivers sitting on a table and have suggested that you go back to a simple open baffle, both of which have been helpful, no?

To say it’s an almost pure copy of the PureAudioProject is not really true at all if PAP doesn’t use the SAL driver. That’s the tricky part of any multi-way speaker -figuring out the crossover. My point was that a second SAL may or may not sound a bit better than a single one but it’s not going to get you deeper bass or solve your problem with the woofers. What is the problem you think you will solve with more SAL drivers? As Planet 10 points out, to use a second SAL to be more relative bass you’ll still need a filter to roll off the top end of the second SAL so the bass seems relatively stronger. A single filter is going to be easier to design by trial and error but still, won’t get you much deeper bass.

You have some parts, already why not take the bull by the horns and learn how to connect the driver properly to the woofers? I’ve tried to help by mentioning what I see as possible problems to look into. They may or may not be all the solution, but it’s very tricky to get right, so that’s a reason to not try I guess.

My guess, and is only a suggestion, is the SAL has deeper bass that most full range drivers so probably the crossover point to the woofers needs to be lower frequency. The woofers are putting out a lot of sound in the upper base right where the SAL is also putting out a decent amount of sound so probably way too much mid bass. And- to get the decent bass the SALs have, Frank the driver designer, had to trade away some efficiency so you probably need to diminish the output of the woofers which are probably tremendously louder than needed to match the SALs.

Why do some designs have 2 woofers when they are way too loud? Well even woofers tend to not be the most efficient at lower bass so people filter them so they have enough output at deep bass and then roll off the upper bass with a filter to make the upper bass match the output of the full range to make a unnoticeable connection. As I also mentioned turning down their volume (probably a lot) with an Lpad would be a start to see if it helps but no doubt not enough in itself. Changing the crossover components to be at a lower point is probably needed.

I think the miniDSP is a great idea. My suggestion was that you could make your speakers similar to some model on THIS thread, ie Laverda. He also has Eminence 15 drivers but I believe he has the 15 Alphas and you have the 15 Betas. Mr. Pass tends to prefer the Betas so that’s a good thing, however it means that Laverdas settings won’t work exactly for you but might get you closer. Some kind of measuring mic system is another good idea which I think you mentioned