Flex Your PCD Mettle:

[fastbike1]

Re: Flex Your PCD Mettle:

Fs is 44.4. No point in trying to tune too low. The PA310 isn't going to go below mid 40's.

Porting help please.

The more I play with winisd the more confused I am getting on porting the 1.65 CU/FT PE trap box and the PA310-8 for the Econowave SR Compact. Porting them low like 32 seems to really roll off the low end on the graph porting them higher like 50 looks better but in the past porting things that high got me poor sound quality (may have been my lack of other skills) so does someone have a porting recomendation? I would like to use a 3" port or 2 but it looks like 2 may be a tough fit.
Thanks,
Mike

[Mayhem13]

Re: Flex Your PCD Mettle:

Hi Mayhem,

Thank you for all the tips, I guess x max is the biggest limiting factor, that is why i originally wanted to use the Beyma 10G40. This driver has got over twice the x max pluss decent extension and is only 1db less efficient. It is a question of which driver is cleaner in the mid range

Not really Stu as the Beyma's not going to get you any more LF extension than the 2510. In the pro world, 10-12" drivers are considered midbass hence the fairly wide band use and lighter cone. An active subwoofer is your best option. There's some killer deals on the QSC parts stroe site on B&C 18" subs......check em out.

[Cerdic]

Re: Flex Your PCD Mettle:

Porting help please.

The more I play with winisd the more confused I am getting on porting the 1.65 CU/FT PE trap box and the PA310-8 for the Econowave SR Compact. Porting them low like 32 seems to really roll off the low end on the graph porting them higher like 50 looks better but in the past porting things that high got me poor sound quality (may have been my lack of other skills) so does someone have a porting recomendation? I would like to use a 3" port or 2 but it looks like 2 may be a tough fit.
Thanks,
Mike

Don't know if I have a great answer to that, but I was planning on porting my SR build with the 310-8s to 53hz in a 1.6 cuft (net) box, and crossing from the SRs to my sub at 80hz. I should have them up and running within the week. :^) I thought about crossing them lower for a more overdamped slow rolloff, but was concerned that I would end up with a gap at my chosen crossover frequency range to the sub. To hedge my bets, I'm making the back removable, both for rear mounting the woofer easily, as well as being able to replace the port and tweak the tuning frequency if I don't like how it's behaving in the room.

Best,
C.

[Cerdic]

Re: Flex Your PCD Mettle:

My LCR SR build is underway!!

I ended up with a 1.6 cuft (net) box, exterior dimensions 16.5 x 25.5 x 11.25, with a 1" thick front baffle. This will allow me to recess the waveguide 1/4" to flush it with the front baffle, and rear mount the 310-8 for an effective 3/4" offset. The shallow depth will allow me to toe-in the speakers up to 25 degrees behind my AT screen (enough to have them cross about 2 feet in front of my primary seating).

All the parts have been cut, the sides top and front baffle have been glued up, and today I routed the recess for the waveguide. What a pain that was.

I'm now at the part I've been hedging back and forth for since the start of this process - the cutting out and rounding over of the woofer hole. I'm looking at an 11" hole, to allow enough wood left to mount the woofer on the rear of the baffle. Any difference sonically between:

1: Set the woofer hole 3/8" below the waveguide and use a 3/8" roundover bit - the roundover just ending at the baffle. Upside - best aesthetics in my mind. Possible downside: increasing c-c spacing by 3/8" and affecting the vertical polars by...?

2: Cut woofer hole right up against baffle with no roundover - Just like Zilch did in his proto. Upside: maintain 10.5" c-c spacing. Downside: not real pretty. Any negatives to having a sharp edge there?

3: Cut woofer hole right up against baffle with 3/8" roundover - would effectively remove some of the waveguide between the lower center 2 screw holes (any more roundover might cut into those holes - so measure twice for those of you considering a 3/4" roundover!). Upside - maintain c-c spacing. Downside - not quite as clean of a look, and is there any likely downside to truncating the waveguide slightly in that lower section of the WG?

If I can't make up my mind before tomorrow, I'll just have to start tackling the crossover. :eek:

And no, there are no pictures yet, but yes, it really is happening. :D

Best,
C.

[Zilch]

Re: Flex Your PCD Mettle:

Congratulations on getting started! This looks like a good design for those with limited space behind an AT screen. Don't know if it shows in any of the pics, but my SR Compact cabs are wedge-shaped with a 30° angle. They were designed and built by my friend John as floor monitors. Duke's "Rhythm Prisms" are more extreme, as I recall, more like 45°, to meet the Parham/Geddes protocol for two-channel.

QSC waveguide? The KDT kit cabs come with the woofer hole precut, and the 11" woofer hole is right at the edge of the flange. I have stared at this for several months, now, and it appears that, once the waveguide is flush-mounted, a roundover as large as 3/4" might be used there, but like you, I'll likely start with something smaller to make sure there's enough flange meat left in the center to still make a good seal. As you suggest, it looks like 3/4" might cut into the mounting hole counterbores; it's going to require an "empirical determination."

[I'm pleased to have you well ahead of me on this one.... :p ]

[Skywave-Rider]

Re: Flex Your PCD Mettle:

Question from a guy with a router who has never used it:

For argument's sake, is a 3/4" roundover bit actually going to cut an arc 3/4" measured from, let's say, the speaker cut out to the point where the arc levels-out with the baffle?

[Zilch]

Re: Flex Your PCD Mettle:

Question from a guy with a router who has never used it:

For argument's sake, is a 3/4" roundover bit actually going to cut an arc 3/4" measured from, let's say, the speaker cut out to the point where the arc levels-out with the baffle?

Yup, the bit is like 2" diameter, with a 1/2" diameter bearing on the axis....

[Big Stogie]

Re: Flex Your PCD Mettle:

Don't know if I have a great answer to that, but I was planning on porting my SR build with the 310-8s to 53hz in a 1.6 cuft (net) box, and crossing from the SRs to my sub at 80hz. I should have them up and running within the week. :^) I thought about crossing them lower for a more overdamped slow rolloff, but was concerned that I would end up with a gap at my chosen crossover frequency range to the sub. To hedge my bets, I'm making the back removable, both for rear mounting the woofer easily, as well as being able to replace the port and tweak the tuning frequency if I don't like how it's behaving in the room.

Best,
C.

I am in the same boat, I am going to spin the wheel and go 50HZ with a slot port across the bottom rear. I think it will be OK
Mike

[Mayhem13]

Re: Flex Your PCD Mettle:

50hz is too low for 1.6cuft net. Better closer to 55hz.

[Cerdic]

Re: Flex Your PCD Mettle:

Congratulations on getting started! This looks like a good design for those with limited space behind an AT screen. Don't know if it shows in any of the pics, but my SR Compact cabs are wedge-shaped with a 30° angle. They were designed and built by my friend John as floor monitors. Duke's "Rhythm Prisms" are more extreme, as I recall, more like 45°, to meet the Parham/Geddes protocol for two-channel.

QSC waveguide? The KDT kit cabs come with the woofer hole precut, and the 11" woofer hole is right at the edge of the flange. I have stared at this for several months, now, and it appears that, once the waveguide is flush-mounted, a roundover as large as 3/4" might be used there, but like you, I'll likely start with something smaller to make sure there's enough flange meat left in the center to still make a good seal. As you suggest, it looks like 3/4" might cut into the mounting hole counterbores; it's going to require an "empirical determination."

[I'm pleased to have you well ahead of me on this one.... :p ]

I didn't realize that your SR compact cabs had a 30 degree angle built in. In Sketchup, I ran a design with a built in 25 degree baffle, along the same lines as your SR compact build and the rhythm prisms (which intrigued me), and by going with my 11 1/4 in deep rectangle build, I was able to get up to 25 degrees of toe-in and have a whole lot simpler carcass construction - not a hard decision.

Today I cut the woofer holes - tight to the QSC waveguide hole. I plan to rout the 3/8" roundover right into the waveguide. Rather than throwing caution to the wind and hope I don't mess up the waveguides, again I fell back on Sketchup and mocked up the roundover profile. As it turns out, with a 3/8" roundover, at the top dead center of the woofer, only 1/32" of the WG gets completely removed. The rest is just shaved thinner. -Should- work just fine.

Other progress includes mounting the flange to hold the removable back, adding in a T shaped cross-brace between the woofer and WG, and making mounting rings for the ports. Doesn't seem like much, but everything takes a bit longer when it's x3.

Alright, I REALLY need to take some pictures...

Best,
C.

[Skywave-Rider]

Re: Flex Your PCD Mettle:

...

Alright, I REALLY need to take some pictures...


C.

Yes.

Good idea on Sketchup. I started playing with that a bit today. I can now see where software assistance is essential when making roundovers which cut into vital parts.
Thumbsup!

[Stu]

Re: Flex Your PCD Mettle:

I am about to build 3 x Econowave Delite 10 for LCR crossed at 50hz to my subs for my HT, can any one give me their unbiased opinion on listening tests for this use and do you think it will sound better than my Paridigm S8v2 mains. Will this Delite be ok for centre use as well?

[Zilch]

Re: Flex Your PCD Mettle:

http://techtalk.parts-express.com/showthread.php?p=1665327#post1665327

For my own part, XT1086 sat around here for a long time; when I ultimately used them in Delite 10 with DE250 drivers, they certainly did not disappoint....

[Mayhem13]

Re: Flex Your PCD Mettle:

Well, finally getting ready to start on my own Ewaves tommorrow.:D I'll be using the super budget XD120 and the Eminence Deltalight 2510 in a sealed 1cuft enclosure. These will be actively crossed to 3.3 cuft ported bass bins using the venerable RSS315HF which will do double duty as stands. The 2510 does really well sealed with an F3 of 95hz. I've been trying to come up with an aesthetically pleasing design as these will probobly serve me long term, and so i arrived at a modular approach similiar to Wilson Audio's Maxx3's



So please tell me what you think?

[Erich H]

Re: Flex Your PCD Mettle:

Well, finally getting ready to start on my own Ewaves tommorrow.:D I'll be using the super budget XD120 and the Eminence Deltalight 2510 in a sealed 1cuft enclosure. These will be actively crossed to 3.3 cuft ported bass bins using the venerable RSS315HF which will do double duty as stands. The 2510 does really well sealed with an F3 of 95hz.

So please tell me what you think?

I think that sounds great. I'm looking at something sort of similar, at least I think so. :D

On those 2510's, if the boxes were ported and tuned around 70hz or so, do you think that would be enough for a center channel? Or would it not give enough powerful bass output? I'm not sure what a center channel needs to go down to and I know most cross them over around 80hz. But I'm debating if I should also put two NHT 083's in with my center channel and use the B-20 amp. Might be too much overkill though.

How long before you start your project? I can't wait to see it.