Hi Doug,
Tell the wife I'm sorry for the speaker induced bipolar episode, and that all men cuss when $hit doesn't work.
- I had only modeled the drivers in series, but I don't see a perceptible change in the model with a parallel connection.
- I think it's extremely important that both drivers see exactly the same signal.
- The recommendation for stuffing is certainly the next step to improve the group delay/"echo", it will improve sound quality and smooth the bump in the upper bass. I don't have a way to calculate the amount of stuffing but if you are wanting to try putting a very small amount below the drivers and extending around the first bend toward the bottom should help. Realistically though, before adding stuffing to the equation you should evaluate LF cutoff and and decide if it's too lean in the low end.
- I know there is a bump in the ~120Hz area I figured you were looking for a bit of a bump when you mentioned raising the crossover to 100Hz and I figured 80Hz 24dB slope AVR LFE out would match it up nicely. It appears you have a different setup?
- Looking at the spaghetti wire on the test bench makes me wonder if the 4ohm setup had some dampening factor/output impedance type of issue, possible bass boost on the test bench amp would make it funky sounding too.
- At any rate the Rev is right on about the need for power ~20w is enough to get these going. The "box" is ~87dB @1w/2.83v 8ohm 2pi, not so shabby IMO. You have like 240w per driver on tap running 4ohm stereo, a little more than needed methinks.
- So what now? I think without driving yourself nuts about the top end see if it has enough low bass. We can trade some efficiency/output for more extension, switch to a positive taper/TH and get more output but only 40Hz cutoff.
Tell the wife I'm sorry for the speaker induced bipolar episode, and that all men cuss when $hit doesn't work.
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Neo,
I know I sound like a crazy person, unusable - to sounds great, and all I did was move a couple of wires around. I find it hard to believe myself.
The signal is flat; a vintage "black box" amplifier 120watts per channel, only using one side now. The active crossover is also very modest. There was something very strange going on with the 4ohm per driver connection.
That is good quality 14 gauge speaker wire, I just removed the jacket. I did think that the wire might be "too long" but as it turns out, not the case.
[never use long runs of speaker wire for sub woofers]
If I was to look for an amp, what should I look for? There is $99 plate amp available, it is about the same watts though.
I did use a flashlight to see if the woofers were bobbing at the same time (in the series connection), they did not appear too (but they never do).I did slide a little foam in the port, can experiment with that a bit.
The medex is a pretty tough material, way more reflection than MDF. You may have noticed I do tighten the boxes down like a gorilla, they are tuning fork tight.
Switch the angle?...gesh I think the box is doing very well, I would hate changing it. I could make another one, maybe add some damping behind the woofers (I may be able to do that now).
*I guess some builders make the last 12” of the “mouth” removable, that way you can access the woofers; could always make a few small holes for long screwdriver.
I know I sound like a crazy person, unusable - to sounds great, and all I did was move a couple of wires around. I find it hard to believe myself.
The signal is flat; a vintage "black box" amplifier 120watts per channel, only using one side now. The active crossover is also very modest. There was something very strange going on with the 4ohm per driver connection.
That is good quality 14 gauge speaker wire, I just removed the jacket. I did think that the wire might be "too long" but as it turns out, not the case.
[never use long runs of speaker wire for sub woofers]
If I was to look for an amp, what should I look for? There is $99 plate amp available, it is about the same watts though.
I did use a flashlight to see if the woofers were bobbing at the same time (in the series connection), they did not appear too (but they never do).I did slide a little foam in the port, can experiment with that a bit.
The medex is a pretty tough material, way more reflection than MDF. You may have noticed I do tighten the boxes down like a gorilla, they are tuning fork tight.
Switch the angle?...gesh I think the box is doing very well, I would hate changing it. I could make another one, maybe add some damping behind the woofers (I may be able to do that now).
*I guess some builders make the last 12” of the “mouth” removable, that way you can access the woofers; could always make a few small holes for long screwdriver.
The Match Up
Going back to the Iso box in a new, slighly bigger box.
I tried several companation in WinISD, it looks like the 10" PR in a 1.4cf box is the best, although there is a 1.8db rise @35hz (hardy a minnow tail).
The box in mind is a keystone, 15 degree angles, 10" PR (40-50grams) in the back, 2 PE 6 1/2" woffers in the front.
6-1/2" Subwoofer Speaker 299-114
Dayton Audio SD270-PR 10" Passive Radiator 295-494
Going back to the Iso box in a new, slighly bigger box.
I tried several companation in WinISD, it looks like the 10" PR in a 1.4cf box is the best, although there is a 1.8db rise @35hz (hardy a minnow tail).
The box in mind is a keystone, 15 degree angles, 10" PR (40-50grams) in the back, 2 PE 6 1/2" woffers in the front.
6-1/2" Subwoofer Speaker 299-114
Dayton Audio SD270-PR 10" Passive Radiator 295-494
Hi,
I don't know where you get a 1.5dB rise at 35Hz from. My modelling
indicates its another "boom box" with a 7dB bass peak around 40Hz.
Around 1cuft with the PR having added mass to to tune to 25Hz
is near flat and extended, but with a inevitably sharp cut-off due
to the high Qts of the drivers.
I can't get a flat response with 1.4 cuft.
rgds, sreten..
I don't know where you get a 1.5dB rise at 35Hz from. My modelling
indicates its another "boom box" with a 7dB bass peak around 40Hz.
Around 1cuft with the PR having added mass to to tune to 25Hz
is near flat and extended, but with a inevitably sharp cut-off due
to the high Qts of the drivers.
I can't get a flat response with 1.4 cuft.
rgds, sreten..
Glad you got it sorted out Doug
- Looking around, the current plate amp situation is not looking good. You could use a Dayton SA25 and a pair of Aura NS6 for similar output in a slightly larger box with 90dB 1w/2v 4ohm efficiency. NS6 probably has better non-linear performance too.
- There would be nice improvement in the group delay on the upper peak, it would shift up to ~150Hz and also be half the amplitude=win-win. The bonus is the amp would fit in the box just under the mouth and allow you to adjust the stuffing=win.
- I don't see any manual for the SA25, it would be nice if there was a HPF that we could mod. I like the BASH amps but they are WAY more power than you need.
- Do the drivers hold up on material that goes below tuning?
Plate amp option...
MCM Part #: 50-6268 should work with the 299-114 setup, though it won't fit in the box.
Too bad the MCA2550E is NLA.
MCM Part #: 50-6268 should work with the 299-114 setup, though it won't fit in the box.
Too bad the MCA2550E is NLA.
I don't like cutting into cabinets anyway; go through all the trouble to make them solid.
I bet the MCM 50-6268 goes on sale.
Don't have to turn the volume knob much with the 200 watt amp, harely touch it. MCM Audio Select 200 Watt Subwoofer Amplifier Module | 50-6263 (506263) | MCM Audio Select
I bet the MCM 50-6268 goes on sale.
Don't have to turn the volume knob much with the 200 watt amp, harely touch it. MCM Audio Select 200 Watt Subwoofer Amplifier Module | 50-6263 (506263) | MCM Audio Select
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Not exactly, it's a TH for 9 NS6's. 102dB/w/2v per pair. It's based on an earlier design, these are best for BIG spaces and outdoors. BASH 300 to run a pair of these =
What you have is tapped, but it's more of a TL or pipe. It's average efficiency like other resonant/ported alignments. It's like ~2-3% vs 10% efficient for the pair. Better stuff is on the order of 30% efficient.
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Neo,
This speaker you designed will be hard to match (or come up with something better). Since you only need 2 drives and sheet of 1/2" material, you have the edge there.
The box doesn't need a grill and an only a low power/cost amplifier. The 9" width is very nice also.
We played t all day today; the bass is very strong/low, a very good design. I will build another so we can have a pair.
Thanks to you and reboden!!
This speaker you designed will be hard to match (or come up with something better). Since you only need 2 drives and sheet of 1/2" material, you have the edge there.
The box doesn't need a grill and an only a low power/cost amplifier. The 9" width is very nice also.
We played t all day today; the bass is very strong/low, a very good design. I will build another so we can have a pair.
Thanks to you and reboden!!
A couple of thoughts:
The box in post #28 is a 1cf box (gross volume: 1.14cf).
If I was add .3 CF to the back, it wouldn't change it that much, not a 7db jump; I doubt it would even be detectable.
The Keystone tower box has a base of 10.5" (front) and 17" (back). I cannot decide if to make the box 17" tall-1.12cf OR 21" tall-1.38cf, however, I think this may be splitting hairs.
Hi ODougbo,
Just for your information:
NEO Dan's box from Posts # 21/23/24/26 and revised in Posts #50/53, the one for which you are showing construction pictures in Posts #61/65/74 is called a T-TQWT (tapped tapered quarter wave tube) a design that bjorno has been trying to popularize here for years.
In Hornresp we use the TH (tapped horn) enclosure type to model it, but it is not a tapped horn, more like a reverse tapered transmission line (starting big at the back of the driver and getting smaller towards the mouth/terminus) with the driver tapped inside the line path.
Hornresp and AkAbak have made accessible the modeling of a whole family of tapped horn/line/duct loudspeaker enclosures, most of which will benefit from the use of some absorptive treatment in the horn path, and need steep high and low cut filters. You should build in some access to the hornpath to add, and experiment with e.g.: poly-fill batting around the area behind the drivers and in the corners.
For general information and references see these threads:
Fiddling with Hornresp - Peerless 831759, and
Tang Band Tang Band W8Q-1071F 8 X 12 box reccomendation, and
search the forum e.g.: for bjorno and T-TQWT.
Regards,
Just for your information:
NEO Dan's box from Posts # 21/23/24/26 and revised in Posts #50/53, the one for which you are showing construction pictures in Posts #61/65/74 is called a T-TQWT (tapped tapered quarter wave tube) a design that bjorno has been trying to popularize here for years.
In Hornresp we use the TH (tapped horn) enclosure type to model it, but it is not a tapped horn, more like a reverse tapered transmission line (starting big at the back of the driver and getting smaller towards the mouth/terminus) with the driver tapped inside the line path.
Hornresp and AkAbak have made accessible the modeling of a whole family of tapped horn/line/duct loudspeaker enclosures, most of which will benefit from the use of some absorptive treatment in the horn path, and need steep high and low cut filters. You should build in some access to the hornpath to add, and experiment with e.g.: poly-fill batting around the area behind the drivers and in the corners.
For general information and references see these threads:
Fiddling with Hornresp - Peerless 831759, and
Tang Band Tang Band W8Q-1071F 8 X 12 box reccomendation, and
search the forum e.g.: for bjorno and T-TQWT.
Regards,
Another construction pic
tb46,
All new to me, only saw a few pics of them on DIY in the last few months.
Again, apologies for the negative posts, it works great; now that I switched to a plate amp instead of the stereo amp.
Not really having an issue with "too much middle", I guess if it was ear level, I probably could hear some. I did slide a 1/2" piece of foam in the mouth.
I'm going to parallel connect both to one amp, 2 - 8ohm loads.
I think there is 1/2 a sheet of MDF left over, maybe get two out of one sheet.
tb46,
All new to me, only saw a few pics of them on DIY in the last few months.
Again, apologies for the negative posts, it works great; now that I switched to a plate amp instead of the stereo amp.
Not really having an issue with "too much middle", I guess if it was ear level, I probably could hear some. I did slide a 1/2" piece of foam in the mouth.
I'm going to parallel connect both to one amp, 2 - 8ohm loads.
I think there is 1/2 a sheet of MDF left over, maybe get two out of one sheet.
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Man Doug,
You are QUICK! Oliver is right bjorno is "the" guy with all the t-tqwt chops, he has a different SW package(MJK worksheets) to model with. I had hoped you would have an idea for what you like/dislike or feel on these, but I see that you are building a pair so you can integrate them in your system. Happy listening I think we may be able to refine these if you have further interest.
Also looking at the NS6+SA25 combo for >$60 seems like a neat idea if anyone is interested.
You are QUICK! Oliver is right bjorno is "the" guy with all the t-tqwt chops, he has a different SW package(MJK worksheets) to model with. I had hoped you would have an idea for what you like/dislike or feel on these, but I see that you are building a pair so you can integrate them in your system. Happy listening
I think we may be able to refine these if you have further interest.Also looking at the NS6+SA25 combo for >$60 seems like a neat idea if anyone is interested.
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