The beyma 12br70 might worth to look at in 68L:
43/35/25 closed
39/33/23 vented
People can choose what they prefer in there room blocking the port.
Also if they whant to make a tower increasing the height and depht :in 120L for exemple:
40/32/21 closed (almost the same)
30/26/20 vented (no need of a sub)
Just making a tower with same footprint should arrive around 100L:
33/28/21 vented
43/35/25 closed
39/33/23 vented
People can choose what they prefer in there room blocking the port.
Also if they whant to make a tower increasing the height and depht :in 120L for exemple:
40/32/21 closed (almost the same)
30/26/20 vented (no need of a sub)
Just making a tower with same footprint should arrive around 100L:
33/28/21 vented
In this day and age, with all simulation/design software, is a prototype really necessary...? At most perhaps build the intended baffle and verify the simulation results?
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That beyma is very good and useable to obave 1khz even. I used in it in a bigger cab for outside use tuned very low but you don't need that low for a monkey coffin. I would use a 70L sealed with this driver, that has an F6 (what matter for sealed) of 40Hz. It's also easy to build like that.
German Hifi-selbstbau measured a surround resonance at 600 Hz creating a notch:
https://www.hifi-selbstbau.de/index.php/hsb-datenblaetter/tieft/beyma-12br70
But they still highly recommend the driver.
Cone breakup information in a response plot will be wrong for other angles. Breakup is understood through these multiple measurements but the information will be absent.
that is a typical notch from measuring to close (at 20cm) where the mic create phase cancelations i think. I did not see that in my own measurements (at least not that deep). I don't have those here anymore as it was not a build for me. There is a reason why it's better to measure from a distance for above the shroeder frequency (where room plays less a role). But it's true that there is an influence from the surround, easch speaker has that (some more than others).
And also, it's a minor notch, not something that will be hearable in reality. I know i cross this driver at 900Hz (48dB/oct with dsp) to a CD in horn, and it sounds and measures good. I'll have to ask the owner for the measurements if i can publish them.
That 12BR70 looks good. Just a thing to know, sensivity is more 90,5 dB when you put the T&S to compute the datas. So close to a hifi driver à la SLS12", but very good price. Serious candidate for the low budget camp.
You can also check Qcomponents, generally they're less expensive than Solen for the same Beyma drivers. They also carry Celestion and B&C.
Does anyone have an opinion on what an undersized box with a Q=.9 sounds like? How about Q=.8?
Anyone else have issues lifting a 100L box? Should the speaker weight be a concern? Would it deter you from building one that big? I have a 100L sub, but it's raw MDF. I might paint it someday, but I'm not looking forward to it.
Anyone else have issues lifting a 100L box? Should the speaker weight be a concern? Would it deter you from building one that big? I have a 100L sub, but it's raw MDF. I might paint it someday, but I'm not looking forward to it.
I'm referring to a sealed box Q. If the woofer qts is say about .4, but the box is smaller than ideal, does it have any sound quality issues that should be avoided. The sim I posted for the 12" Peerless is an example. I've read some opinions in old books, but wondered if anyone thinks a higher box Q should be avoided.
The bass response in my room is pretty wild.
The bass response in my room is pretty wild.
Generally speaking, in a passive speaker without the benefit of DSP, a sealed box Qtc from 0.7 to 0.8 sounds very good and is very easy to work with. The low Qtc boxes like 0.6 and below, those do have more bass extension, but they generally require more baffle step compensation, which drives the sensitivity of the whole speaker system down.
A Qtc=0.9 can probably work well, but I have no experience with a passive design Qtc=0.9. I imagine the BSC and voicing has to take into account the slightly elevated bass response for the octave above Fb.
As far as weight goes, for me, I don't want to lift more than 50 lb. But I am not likely to build this speaker.
A Qtc=0.9 can probably work well, but I have no experience with a passive design Qtc=0.9. I imagine the BSC and voicing has to take into account the slightly elevated bass response for the octave above Fb.
As far as weight goes, for me, I don't want to lift more than 50 lb. But I am not likely to build this speaker.
So would you think the 12" Peerless shoehorned into a 60L box would be a good option? The Q would be .9 if the resistance in the x-over coils is .8 ohms. The actual resistance in the x-over may be lower, and that would lower the box Q some.
Edit.. Sorry....You kind of already commented on the higher Q of .9.
Edit.. Sorry....You kind of already commented on the higher Q of .9.
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