Frustrated building PA speaker

[der]

Provided Link: Woofer in Question


I wanted to build a modest-size PA speaker, and chose the pym1278 (292-232) 12" driver since it's listed as a PA speaker, is relatively inexpensive, features a VAS of only 2.11, and is pretty efficient.
I paired it with a Selenium D210i (263-236) plus a basic Goldwood GM-600PB Horn, and plan to bi-amp it.
Now, the fs. on that woofer is a relatively high 63 Hz., I know, but I really don't seem to be getting any bass out of it, despite building the suggested enclosure (3/4" particle, braced in 2 dimensions, two ducts, also fiberglass on 3 walls). Have any of you pundits had any experience with this particular loudspeaker, maybe have some suggestions? I'm not terribly impressed with the tweeter, either, to tell the truth.
Thanks!

[Max_Andrews]

The woofer was not the best choice, the pyle sheet shows it with an F3 of 60hz in their suggested box. More importantly, the woofer only has 1.8mm of xmax, so it will distort with even modest power levels.

This one is much better and should work in the box you have now: <A HREF="http://www.partsexpress.com/pe/pshow...number=290-416">http://www.partsexpress.com/pe/pshow...number=290-416</A>

But I dunno if you can return the pyle ones still, give PE a call

[Max_Andrews]

If you do swap out the woofers for the eminence ones you'll need to put in different length vents. You can use winISD to compute that, or I can do it tomorrow.

For the horn, why the goldwood one? You'll likely have to re-make the baffle for a new one, but a biradial such as this one will work better:
<A HREF="http://www.partsexpress.com/pe/showd...number=264-308">http://www.partsexpress.com/pe/showd...number=264-308</A>

What's your bi-amp crossover setup? The tweeter should be used no lower than 2khz.

Hope this helps!
Best,
Max

[Chris Roemer]

> If you do swap out the woofers for the
> eminence ones you'll need to put in
> different length vents. You can use winISD
> to compute that, or I can do it tomorrow.

> For the horn, why the goldwood one? You'll
> likely have to re-make the baffle for a new
> one, but a biradial such as this one will
> work better:
>
> <A HREF="http://www.partsexpress.com/pe/showd...number=264-308">http://www.partsexpress.com/pe/showd...number=264-308</A>
> What's your bi-amp crossover setup? The
> tweeter should be used no lower than 2khz.

> Hope this helps!
> Best,
> Max

If you go with Max's woofer, plug one of your two 3.5" dia vents. Even better, lengthen that single vent to 2", or just use a 4" d x 3" long vent.

Even though you initially chose a woofer with a smallish Vas, its high Qts (.48) makes for a bigger box. Qts is actually more important than Vas in determining box size. Example: Two drivers with the same Qts (.40): one with a Vas of 2 cf needs a 2 cf (vented) box, one with a Vas of 4, needs a 4 cf box. Two drivers that both have a Vas of 4 cf: one with a Qts of .50 needs an 8 cf (vented) box, one with a Qts of .25 only needs a 0.8 cf box!

[unknownuser]

Provided Link: http://billfitzmaurice.com


> Two drivers that both have a Vas of
> 4 cf: one with a Qts of .50 needs an 8 cf
> (vented) box, one with a Qts of .25 only
> needs a 0.8 cf box!

That low Qts and small box size also kills the low end, so that's not going to cure the problem. The drivers he has aren't going to work well no matter what, they're just too cheep. Chalk this episode up to experience. Designing your own PA cabs seems simple enough, but it isn't. Next time use a tested design. Best bet is one of Bill Fitz cabs.



(Originally posted by: RJ)

[wg_ski]

> That low Qts and small box size also kills
> the low end, so that's not going to cure the
> problem. The drivers he has aren't going to
> work well no matter what, they're just too
> cheep. Chalk this episode up to experience.
> Designing your own PA cabs seems simple
> enough, but it isn't. Next time use a tested
> design. Best bet is one of Bill Fitz cabs.

You're not going to get bass out of a two cubic foot PA box no matter who designed it. And Fitz will be the first one to tell you that. Time to build a sub.

[billfitzmaurice]

> You're not going to get bass out of a two
> cubic foot PA box no matter who designed it.

True. The smallest full range cab design I offer is 2.7 cu ft., loaded with a ten. The smallest pro-sound sub I do is 5 cu ft, to be used no less than two at a time. A .8 cu ft cab for below 200 Hz just ain't gonna fly.

[vasyachkin]

> I wanted to build a modest-size PA speaker,
> and chose the pym1278 (292-232) 12"
> driver since it's listed as a PA speaker, is
> relatively inexpensive, features a VAS of
> only 2.11, and is pretty efficient.
> I paired it with a Selenium D210i (263-236)
> plus a basic Goldwood GM-600PB Horn, and
> plan to bi-amp it.
> Now, the fs. on that woofer is a relatively
> high 63 Hz., I know, but I really don't seem
> to be getting any bass out of it, despite
> building the suggested enclosure (3/4"
> particle, braced in 2 dimensions, two ducts,
> also fiberglass on 3 walls). Have any of you
> pundits had any experience with this
> particular loudspeaker, maybe have some
> suggestions? I'm not terribly impressed with
> the tweeter, either, to tell the truth.
> Thanks!

my friend built a 8" speaker out of pyle pro and had the exact same problem - no bass AT ALL

he brought it to me, we hooked it up to my 2400W amplifier and digital equalizer and boosted the bass by about 30 decibels ... it started making terrible distortion and still no bass ... he threw the speaker out to the garbage

my friend says that not all cheap-a$$ speakers like Pyle or Pyramid are worthless, that sometimes they accidentally make usable models ... but often what they make is completely useless as well

considering that Pyle Pro costs about 10% of what Beyma costs it doesn't really need to work at all in order to sell so they don't really have any incentive to fix their drivers ...

[wg_ski]

> my friend says that not all cheap-a$$
> speakers like Pyle or Pyramid are worthless,
> that sometimes they accidentally make usable
> models ... but often what they make is
> completely useless as well

Unfit for intended purpose. The driver in question was intended for vocal wedges. Slap one in a reflex box, throw in a horn, and expect to DJ with it. Yeah, right.

> considering that Pyle Pro costs about 10% of
> what Beyma costs it doesn't really need to
> work at all in order to sell so they don't
> really have any incentive to fix their
> drivers ...

The chinese made units are jun-que. Qts's through the roof and about the same sensitivity as a Dayton Classic home-audio driver. I wouldn't call them 'PA drivers' at all. The US made units are built to spec from Eminence and are almost identical to comparably-priced Greek Letter series units. No surprise there. You could probably get an equivalent (and equivalently cheap) vocal wedge driver from Beyma or any other pro driver manufacturer if you wanted one.

[billfitzmaurice]

> my friend built a 8" speaker out of
> pyle pro and had the exact same problem - no
> bass AT ALL

'Tis a poor carpenter who blames his tools, and a poor builder who blames his drivers. Failure to properly choose a driver for the intended use is his fault, not Pyle's.

> considering that Pyle Pro costs about 10% of
> what Beyma costs it doesn't really need to
> work at all in order to sell so they don't
> really have any incentive to fix their
> drivers ...

An adage comes to mind: 'You get what you pay for.' Your friend did. Get over it.

[der]

Provided Link: a Beheringer example


Hey, thanks a lot everybody for chiming in on this problem! I gave the speaker another audition tonight and don't feel QUITE as dissatisfied as before--there is SOME bass, just not very deep (just "shallow bass"?). The tweeter is actually pretty serviceable. On the whole the things puts out quite a bit of sound, and is particularly good in the midrange (i.e. vocals). Perhaps the woofer just needs to be broken in some(?) I actually pulled the ducts out, and perhaps just having ports somehow helped. But I want to respond to some of the points and suggestions that have been made.

About the contention that you can't get bass out of a 2 cubic foot speaker (the design in question is around that--not .8) , I would counter that with examples such as JBL Eons and similar units by Mackie, which not only are small in size, but also quite lightweight (I admit I'm puzzle how that's possible without high-density material). I'm not looking to fill an auditorium, and something (nearly) comparable to those examples are what I'm after, and I think they produce quite decent bass (if not quite into the sub-woofer realm).

My particular woofer, by the way, is indeed built in the U.S. by Eminence.

Given that the cabinet I built is the recommended one, and that PE represents this as a PA driver, I'm wondering just what the intended use of this speaker actually is. I'm feeling just a tad mislead, frankly.

Thank you, Max and CJ for the specific suggestions (and lessons!), though. As for trying to return/exchange the woofer I doubt that's possible since I've akready had it for a few months. This is actually the second cabinet I've built for it since the first was was hastily-built so I thought the acoustic deficiencies were due to that (wrong, it appears).
As for investing another $100 bucks in a different woofer, well, I dunno. I could also just buy something like a Behringer Eon/Mackie imitation for not much more than that and probably be done with it...

Again, thanks all!
- 'Der

[billfitzmaurice]

> I would
> counter that with examples such as JBL Eons
> and similar units by Mackie, which not only
> are small in size, but also quite
> lightweight

They also sound horrible and have no bass. If that's the level of sound quality you're looking to achieve it's an easy goal to reach, but not a worthwhile one. IMO nothing below the SRX line from JBL is listenable, and nothing at all in the Mackie line is. The only JBLs I'd consider owning myself is the VRX line.

[aricaudio]

> They also sound horrible and have no bass.
> If that's the level of sound quality you're
> looking to achieve it's an easy goal to
> reach, but not a worthwhile one. IMO nothing
> below the SRX line from JBL is listenable,
> and nothing at all in the Mackie line is.
> The only JBLs I'd consider owning myself is
> the VRX line.

Bill, You may also need to address that He may have different priorities and listenning experiences than you. So therefore, may not be as picky as what sounds "acceptable". I must admit, I too am picky on what I can listen to for more than 2 minutes on end. I heard some EAW full-rangers with a B&C 15", 3-way design and they sounded great for what they were......but even those could've stood some refinement in the crossover....

Best regards, Aric

[der]

Provided Link: Possible Bill Design (Omni 12)?


Okay, trying to synthesize all this information...
Now that I've built TWO cabinets for this puppy with miserable to mediocre results, what if I tried it in one of Bill's designs, the Omni 12 for instance? Might that resurrect it, or at least be optimal? I mean, I'm going to be building another cabinet ANYWAY since my plan is to take just the raw drivers down to central Mexico, where I will do the final construction, and I don't want to haul cabinets down there. Perhaps some aspects of the design would have to be modified to fit its specific parameters.
Interesting thought, at least; I'm intrigued now having looked at billfitzmaurice.com!
Perhaps he doesn't want to be pushy with his site/plans, but I suspect that my woofer might be a sort of "little brother" to the (also) Eminence Delta 12 which he uses (and which was suggested above).
Obviously I know it wouldn't perform as well as the 12FA, but in many specs it's comparable, and they do have identical Vas (2.4)

Here's how they differ (mine listed first):

Le: 0.77 mH v. 1.45 mH (does THAT matter?)
Fs: 63 v. 51 Hz
Frequency range: 55-5,000 Hz v. 44-3,000 Hz
Magnet weight: 70oz. v. 56 oz. (!)
SPL: 96.5 v. 94.6 dB 1W/1m (! --maybe due to more mids )
Xmax: 1.8 mm v. 4.8 mm

I guess the Xmax and Fs. figures are the most significant, but still, perhaps Bill's cabinet could make this slightly handicapped woofer sing.
Any thoughts?

[aricaudio]

> Okay, trying to synthesize all this
> information...
> Now that I've built TWO cabinets for this
> puppy with miserable to mediocre results,
> what if I tried it in one of Bill's designs,
> the Omni 12 for instance? Might that
> resurrect it, or at least be optimal? I
> mean, I'm going to be building another
> cabinet ANYWAY since my plan is to take just
> the raw drivers down to central Mexico,
> where I will do the final construction, and
> I don't want to haul cabinets down there.
> Perhaps some aspects of the design would
> have to be modified to fit its specific
> parameters.
> Interesting thought, at least; I'm intrigued
> now having looked at billfitzmaurice.com!
> Perhaps he doesn't want to be pushy with his
> site/plans, but I suspect that my woofer
> might be a sort of "little
> brother" to the (also) Eminence Delta
> 12 which he uses (and which was suggested
> above).
> Obviously I know it wouldn't perform as well
> as the 12FA, but in many specs it's
> comparable, and they do have identical Vas
> (2.4)

> Here's how they differ (mine listed first):

> Le: 0.77 mH v. 1.45 mH (does THAT matter?)
> Fs: 63 v. 51 Hz
> Frequency range: 55-5,000 Hz v. 44-3,000 Hz
> Magnet weight: 70oz. v. 56 oz. (!)
> SPL: 96.5 v. 94.6 dB 1W/1m (! --maybe due to
> more mids )
> Xmax: 1.8 mm v. 4.8 mm

> I guess the Xmax and Fs. figures are the
> most significant, but still, perhaps Bill's
> cabinet could make this slightly handicapped
> woofer sing.
> Any thoughts?

I would'nt duplicate the design for the Eminence- the Le and Xmax are enough differences to make them completely different animals in terms of output and tone. You never did mention what size boxes you ended up building for the woofers? I would probably start them off in 2.5 cubic foot each, with a 3" x 7" long vent. The low xmax will make them less accurate when they're moving, though. Also, The high-ish LE would make me wanto tcross them a full octave lower than what your target is. They'll tand to beam in the midrange. Or, go passive and run a 4th order filter with a shaping "zobel" on the woofers. Use target fc for the tweeter (as it's pretty smooth), and experiment with an l-pad to match the levels within reason. Other than that, the woofer's limited xmax is enough of a reason to not go through all the trouble. Then again, what the heck....build them up and use as an experiment to build skill-level, and then buy some better/smoother drivers....it's your call. I have no personal experience with Bill's designs, so I can't comment on them. Best regards, Aric

[aricaudio]

> I would'nt duplicate the design for the
> Eminence- the Le and Xmax are enough
> differences to make them completely
> different animals in terms of output and
> tone. You never did mention what size boxes
> you ended up building for the woofers? I
> would probably start them off in 2.5 cubic
> foot each, with a 3" x 7" long
> vent. The low xmax will make them less
> accurate when they're moving, though. Also,
> The high-ish LE would make me wanto tcross
> them a full octave lower than what your
> target is. They'll tand to beam in the
> midrange. Or, go passive and run a 4th order
> filter with a shaping "zobel" on
> the woofers. Use target fc for the tweeter
> (as it's pretty smooth), and experiment with
> an l-pad to match the levels within reason.
> Other than that, the woofer's limited xmax
> is enough of a reason to not go through all
> the trouble. Then again, what the
> heck....build them up and use as an
> experiment to build skill-level, and then
> buy some better/smoother drivers....it's
> your call. I have no personal experience
> with Bill's designs, so I can't comment on
> them. Best regards, Aric

Doh! It should read "I'd start them off in 3.5 cubic footer"....not 2.5

Aric

[der]

Provided Link: PE plans for Pyle Pro woofer


> Doh! It should read "I'd start them off
> in 3.5 cubic footer"....not 2.5

> Aric

Thanks for that, Aric!
Yeah, my present box is modeled after the PE plans
so it's a 2-1/2 cubic footer.
Interesting your observation about the Le. I am actually bi-amping, so I can dynamically play with the frequency cutoff between woofer and tweeter.
My understanding about horn enclosures, which Bill's designs appear to be, is that they are VERY efficient, and that this is an advantage to a speaker with the specific problem of a low Xmax spec. since not much excursion is needed for high SPLs.

[aricaudio]

> Thanks for that, Aric!
> Yeah, my present box is modeled after the PE
> plans
> so it's a 2-1/2 cubic footer.
> Interesting your observation about the Le. I
> am actually bi-amping, so I can dynamically
> play with the frequency cutoff between
> woofer and tweeter.
> My understanding about horn enclosures,
> which Bill's designs appear to be, is that
> they are VERY efficient, and that this is an
> advantage to a speaker with the specific
> problem of a low Xmax spec. since not much
> excursion is needed for high SPLs.

I hate to say this, but I don't trust the PE woofer plans anymore. It was told that they are supposedly the besty compromise of size and tuning, but most of them are literally unuseable.
Aric

[billfitzmaurice]

> My understanding about horn enclosures,
> which Bill's designs appear to be, is that
> they are VERY efficient, and that this is an
> advantage to a speaker with the specific
> problem of a low Xmax spec. since not much
> excursion is needed for high SPLs.

My cabs are very efficient, but OTOH the last thing you want to do is go the time, trouble and expense of building a good cabinet and then ruin the job by using an unsuitable driver in it.

[der]

> My cabs are very efficient, but OTOH the
> last thing you want to do is go the time,
> trouble and expense of building a good
> cabinet and then ruin the job by using an
> unsuitable driver in it.

So, Bill, I'm glad you chimed in again.
This less expensive Eminence woofer is unsuitable because of the higher Fs: (63 v. 51 Hz) or is it the
Xmax: 1.8 mm v. 4.8 mm? I mean I know it won't perform as WELL given these differences, but mightn't it still be servicable? I will be bi-amping so crossover concerns needn't enter into it.
Or are those differences in specs enough to throw off the entire cabinet design? Perhaps it's just a matter of adjusting a few cabinet dimensions?

I really have no idea what I'm talking about...
:-)