hifijim: that is true. SB woofers and midwoofers are not my cup of tea. On the other hand, their tweeters: SB26ADC, SB29RDNC, SB26STNC, TW29RN, TW29DN, TW29TXN, TW29BN are all very good, BN is currently my favorite.
I think I have an even more interesting thought about this.
Sometimes it doesn't even matter WHY we think something sounds better.
Which is 100% fine and absolutely great.
But let that also be that way and nothing else!
Many people think that we human beings are objective listeners.
And therefor what they hear (or rather think they hear), is the objective truth.
Fact is that we are not objective listeners. Very far from it.
I guess again, some people expect me to add that it's an opinion.
But the research and literature on this, is so rock solid, that I struggle to phrase it that way, so my apologies.
I know certain people and customers, incl myself, that would just not like the sound of something if things don't look or feel right.
Even if that would be basically identical to something else.
What's even more bizarre and fascinating I think, is that if you are even aware of that, you can't switch it off!
My previous point and thought is mostly coming from the idea that I very rarely see good, complete, accurate measurements and data and even less good objective (blind) listening tests.
I am talking about the full set here, spinorama, THD measurements, BL(x), Cms(x), Le(x), compression and the whole thing etc
The only one who comes close and is consistent is Erin.
And I think his subjective listening and objective correlate pretty well.
They also correlate pretty well with my experience.
Btw, I am not talking about his subjective and personal preferences!
Just only about the correlation between what someone hears and what the measurements say.
Do you use those SB woofers also for the low-end, like mid-woofers?
Or just as mid-range?
I was just gonna say, the low-end of the NBAC etc isn't that great.
In fact, and this doesn't really seem to show up even in the Klippel LSI measurements, there is something very odd going on with the suspension.
Some drivers (can't exactly remember which ones) show a very sudden drop in frequency.
Or raise in frequency depending how you look at the problem lol 😉
This seems to be different than just your typical Kms(x)/Cms(x) problem, but it seems to be an issue at lower voltages.
Unfortunately I haven't seen any Klippel LSI measurements of the NBAC range yet, only the CAC;
https://www.erinsaudiocorner.com/driveunits/sbacoustics_sb17cac35-4/
I will plow through some VoiceCoil Magazines, see if I can find anything there.
I did invest in a laser displacement sensor myself, still need to get the hardware running.
But in a bit we'll be able to investigate these things 🙂
Hi, what sensor did you get? And with what software?
Just beginning to contemplate this, been peeking at the Keyence site.
Some guys using software that I'm learning, are starting to experiment with laser data collection.....https://youtu.be/q5qcNEZTEHA?t=194
This is a piece of killer measurement/simulation/FIR software, if you haven't seen it. Check out the full vid.
At this point, I haven't learned enough yet, for a laser try. Waiting to copy something I see done, that I can afford....
I will check out the model number tomorrow.
As for software, I am thinking of actually designing my own board, with probably a rasp pi as host.
Reason is that we have to be able to measure DC as well, which is not possible with any audio ADC (most of them have a HP build in).
I have been looking at USB DAQ's (yes that's a a Q lol), but they are rather pricy.
Data acquisition interfaces.
We only need two channels with not a very extreme sample rate.
Anything between 16 and 24 bits is probably be fine.
The sensors (LDS) are not that expensive at all. Somewhere around 250-450 bucks or so.
What's even more incredible, is how much greater the capability set is, than was shown in the YT vid.
Its' targeted at the large scale pro-sound technicians....system engineers setting up world sized rigs, often with major time constraints.. So competes with Smaart and Systune, etc,
Smaart runs $1300 for full blown, down to $500 for lightest version. Systune, about $800 t& $500. Comparing against those two, makes CL+ which has far greater capability, look like a bargain.
REW's the clear champ for value, being donate ware...and imo has a better capability set than either Smaart or Systune. It's unfortunately hobbled by lack of real-time, and not true dual-channel capability. But for home audio, or even benchwork, hell yeah. That said, adding a REW pro multi-mic license for $100, and making any well due donations, gets at least halfway to $500, imo.
Now with FIR, ...everywhere gets more expensive .....the optional CL+ FIR toolkit is another $500.
But the prosound commercial options are sadly just plain higher still.
The FirDesigner series runs from top dog $490 annual subscription only, to a next level down one-time purchase of $700 but with no support or upgrades past one year for $700, ......down to an overly hobbled version for $250.
AMFG, whom I'm sure your familiar with, doesn't even quote their FIR Maker product online...forcing you to call sales.
Home audio isn't much better imo......Acourate is $450, Audiolense is i'm guessing about $600 by the time you get the needed components.. Imho, both appear a real pain for DIY muti-way, compared to FirD or CL+. There's always the freebie DRC..but with even greater pain.
I'm hoping REW eventually evolves into having a good FIR generator.
The market REALLY needs a simple, affordable "specify target at the driver level" and then generate some FIR !
Sorry all, ......what a rant 🙂🙁
Jim, sorry for going off-topic...laser got me going..
Yep thx, I probably should have included that.
Must say, now that I've experienced the luxury of having a FIR generator, simulator, AND measurement capability all in one program....I'm hooked.
To heck with all the file imports/exports 😀
In other news, the Dayton SIG225-4 woofer has been backordered for weeks, and it will not be restocked until July 12.
The delay has given me time to reconsider this woofer. I really wanted to do a project with it, but the 4 ohm impedance is creating troubles in my simulations. It gives me very little maneuvering room in the crossover design, and depending on what assumptions I make, the impedance can drop as low as 2.4 Ohm. I would regret being in a position where I have to compromise on the crossover design and sacrifice performance just to keep the impedance above 3 Ohm.
I have decided I am more comfortable with an 8 Ohm woofer. The Dayton RS225-8 is a well-known entity, although I have never worked with it before. But the reputation is very good. In simulation, I get a slightly lower F3, and much more favorable impedance curve...
j.
The delay has given me time to reconsider this woofer. I really wanted to do a project with it, but the 4 ohm impedance is creating troubles in my simulations. It gives me very little maneuvering room in the crossover design, and depending on what assumptions I make, the impedance can drop as low as 2.4 Ohm. I would regret being in a position where I have to compromise on the crossover design and sacrifice performance just to keep the impedance above 3 Ohm.
I have decided I am more comfortable with an 8 Ohm woofer. The Dayton RS225-8 is a well-known entity, although I have never worked with it before. But the reputation is very good. In simulation, I get a slightly lower F3, and much more favorable impedance curve...
j.
Looking forward to the progress of this project with the RS225s. I use them in a 2 way and a 3way. Currently in 28litre BR with Kef R coaxial on top in OB.
Have had MCA15 on top as well with 2 back to back Vifa BC25s. Also had a 'sort of MCA12' ( Seas drivers out of a Monitor Audio centre speaker!).
I have the SB17NBAC here too. I had them in a 2 way but the whole project lacked a little something. Would be interesting to see what they do as a mid in a 3 way. I ought to try them again.
Have read all this thread and the knowledge and experience that you guys possess is infectious. Keep it up.
Have had MCA15 on top as well with 2 back to back Vifa BC25s. Also had a 'sort of MCA12' ( Seas drivers out of a Monitor Audio centre speaker!).
I have the SB17NBAC here too. I had them in a 2 way but the whole project lacked a little something. Would be interesting to see what they do as a mid in a 3 way. I ought to try them again.
Have read all this thread and the knowledge and experience that you guys possess is infectious. Keep it up.
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@hifijim - I picked up a quad of SIG225 off eBay and couple of weeks ago. I think the RS225 is probably a good idea, but if you want some actual T/S parameters and impedance of the Signature woofers to compare to the manufacturer's, let me know and I can measure them and post here.
I won't be needing the Sig225 data, but I am sure the information would be useful to someone. If you want to post the data, you can post it here. Perhaps the dedicated SIG thread might be a better place ?
j.
The motor used in the SB17N(B)AC and possibly other SB17 drivers is not very linear above about 2.5mm excursion from memory. This was from a Klippel measurement, maybe one of Vance's. It could explain why as a bass transducer, the quality isn't that good when playing loud or low.
The motor is fine BL(x), the compliance isn't.
https://www.erinsaudiocorner.com/driveunits/sbacoustics_sb17cac35-4/
Compliance is only a lot less important, only creates a bit of HD distortion around Fs.
50% Cms is around 5mm cone excursion.
Don't remember that these were ever tested in VC Magazine.
https://www.erinsaudiocorner.com/driveunits/sbacoustics_sb17cac35-4/
Compliance is only a lot less important, only creates a bit of HD distortion around Fs.
50% Cms is around 5mm cone excursion.
Don't remember that these were ever tested in VC Magazine.
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I recently used the SB17NBAC 8ohm version in a 2-way speaker. It was a sealed box. I thought the quality of the bass was pretty good... tight, articulate... Of course it would stumble at higher SPL, you can only ask a 6" sealed box driver for a moderate amount of bass before the excursion starts to hit the limits.
I never tried to use it in a vented box, and I don't think it would be a good driver for that. The spec Qts is on the high side for BR, and my measured Qts was even higher.
I never tried to use it in a vented box, and I don't think it would be a good driver for that. The spec Qts is on the high side for BR, and my measured Qts was even higher.