Novice stereo subs project with stereo amp.

[chris661]

It must be said - they're a lot better than anything I've been able to get out of that program...

 

[tb46]

Choices, choices....

Hi PJeff,

Build the big Front Mouth (Post #52) outer box w/ a removable front baffle,and try it sealed, then as BR, then as Shadow. And don't forget to tell us about the results . Two Trio12 in large (75 liter and above) boxes will provide considerable low frequency output even in sealed boxes w/ 100W ea. With room gain that may be all you want, and they will have great transient response.

Regards,

 

[planet10]

Thank you for this tb46,
I've played around with that and what i've noticed, with my limited knowledge, is that the extension is somewhat limited in the Shadow enclosure compared to something like a ported 119L box tuned to 20.6Hz(see attachments). Do you see any advantage the Shadow has in other areas? Dave any thoughts?

One always has to keep the room in mind, and that the F3 often used to quanitfy extension is not much use. The response of a woofer should roll off slowly starting fairly high. F10 is a better metric for quantifying extension.

One would actually have to build and measure Shadow's extension as their are no tools to directly sim it.

If you make a woofer that sims flat to 20 (or 30, or even 50 in many rooms), it will have a fat, lifted bottom end, that even if EQed down to flat, may well still have quality issues.

dave

 

[PJeff]

Hi PJeff,

Build the big Front Mouth (Post #52) outer box w/ a removable front baffle,and try it sealed, then as BR, then as Shadow. And don't forget to tell us about the results . Two Trio12 in large (75 liter and above) boxes will provide considerable low frequency output even in sealed boxes w/ 100W ea. With room gain that may be all you want, and they will have great transient response.

Regards,

I really like the idea for comparison sake but I doubt it's the optimal volume for sealed or vented to get a really good idea of what those configurations are capable of.
Thank's for the creative idea though.

PJeff

 

[PJeff]

One always has to keep the room in mind, and that the F3 often used to quanitfy extension is not much use. The response of a woofer should roll off slowly starting fairly high. F10 is a better metric for quantifying extension.

One would actually have to build and measure Shadow's extension as their are no tools to directly sim it.

If you make a woofer that sims flat to 20 (or 30, or even 50 in many rooms), it will have a fat, lifted bottom end, that even if EQed down to flat, may well still have quality issues.

dave

Hi Dave,
How is the F10 a better metric for qualifying extension? Is it because it gives a better idea of the roll off curve?

PJeff

 

[PJeff]

Ok... I slept on it and I've decided to give one of my Shadow variation (Var4.4) a try(Please tell me if you see any problem with my variation... now is the time). Front firing, side mouth, mirror imaged. I'm very intriged by the shadow design so I'm going for it and in order to have something to compare it to, I will build one basic sealed enclosure as well. WinISD gives me a default sealed enclosure of 56.9L for a Qtc of 0.71. Is it optimal for best integration, dynamics and clean sound? My intent is to use them from 60-80Hz and down. If I increase the volume, even to ridiculous values, the Gain curve doesn't change much but the Phase Plot and Group Delay seam to vary in more significant ways... but unfortunately... I do not know how to interpret all that.

So what do you think would be the optimal sealed volume for the Trio12 and could you explain to me why? I would like to further my understanding.

Cheers,
PJeff

PS: The Trio12's are on their way and should be here any day now!!!

 

[kahkonen]

so did this ever get built and how did it sound?

 

[chris661]

Reading through that brought things back.

Also curious about how it went.

Chris

 

[JRKO]

PJeff, did you build them? How do they sound?

pictures pictures pictures

 

[PJeff]

...It's been a while...
Yes... I did build two ''Shadow PJeff var4.4'' but not the closed box(not knowing exactly what size would be ideal). Here's some pics of where they're at...broken-in, without any stuffing or sound treatment inside and still unfinished yet.

How do they sound?!! I've been experimenting a bit on placement and I think they sound pretty good. They're a lot of fun for sure, especially in movies...I did crank them up quite a bit and they never showed any sing of wanting to bottom out.
Besides some frequencies that seams to overwhelm the room(room modes maybe?) the only thing that I would like to improve is the transient/cleanness for music playback.
Do you think stuffing will improve that aspect?

I havent had time to work on them for a little while now experimenting and enjoying since mid september but now I want to get to it and revive this really fun project. (I really enjoyed the building phase... BTW they weigh about 75pounds each)

Thank you for your interest and help
PJeff

 

[nuconz]

what about a variation on this design?

instead of a side mount woofer, mount the woofer in the upper part of the scoop at a 45 angle?