I am wondering how well these components would work together, and what style crossover would be best. I am currently running a pair of 38 Hz Volvotreter tapped horns, "Microbe" 5 inch bookshelves, and a Dayton amp (subs) and Panasonic XR57 class D amp (microbes). These will be the first speakers I have designed myself - I have built the Microbes and volvotreter tapped horns from plans. I like the microbes sound quality wise, but I am looking for more clean output to match the tapped horns.
B&C 8PS21 8" Woofer (as reviewed by Zaphaudio)
Parts-Express.com:*B&C 8PS21 8" Woofer | 8ps21 8" pa midrange cone midrange b&c midrange pa woofer
Eminence PSD:2002S-8 1" Titanium Driver 8 Ohm
Parts-Express.com:*Eminence PSD:2002S-8 1" Titanium Driver 8 Ohm 1-3/8"-18 | compression driver tweeter horn driver screw on high frequency 1" exit i" throat HF PA driver tweeter driver
Dayton H08RW 8" Round Waveguide
Parts-Express.com:*Dayton H08RW 8" Round Waveguide 1" Threaded | horn lens horn tweeter horn bell horn compression driver DaytonAudioWaveguides070109
The box would be about 20L with a port, tuned to 89 Hz and crossed at 100 Hz to the subs from the receiver. I would use the biamp feature of the XR57 to balance the output to the woofer and compression driver circuits, and adjust the time delay between the two. I would have separate low and high pass circuits for the woofer and compression driver.
Questions:
1. Is this a workable setup?
2. What order crossover would be best?
3. What frequency crossover would be best?
4. Will additional padding be needed to ensure somewhat smooth upper frequency response from the compression driver / waveguide?
B&C 8PS21 8" Woofer (as reviewed by Zaphaudio)
Parts-Express.com:*B&C 8PS21 8" Woofer | 8ps21 8" pa midrange cone midrange b&c midrange pa woofer
Eminence PSD:2002S-8 1" Titanium Driver 8 Ohm
Parts-Express.com:*Eminence PSD:2002S-8 1" Titanium Driver 8 Ohm 1-3/8"-18 | compression driver tweeter horn driver screw on high frequency 1" exit i" throat HF PA driver tweeter driver
Dayton H08RW 8" Round Waveguide
Parts-Express.com:*Dayton H08RW 8" Round Waveguide 1" Threaded | horn lens horn tweeter horn bell horn compression driver DaytonAudioWaveguides070109
The box would be about 20L with a port, tuned to 89 Hz and crossed at 100 Hz to the subs from the receiver. I would use the biamp feature of the XR57 to balance the output to the woofer and compression driver circuits, and adjust the time delay between the two. I would have separate low and high pass circuits for the woofer and compression driver.
Questions:
1. Is this a workable setup?
2. What order crossover would be best?
3. What frequency crossover would be best?
4. Will additional padding be needed to ensure somewhat smooth upper frequency response from the compression driver / waveguide?
Use this 2-way xover, sensitivity/impedance@xoverpoint is similar, here 
:
Kit DIY enceintes B&C Speakers Box 8
Kit DIY enceintes B&C Speakers Box 8
:Kit DIY enceintes B&C Speakers Box 8
Kit DIY enceintes B&C Speakers Box 8
8PS21 may be ok, but it looks somewhat peaked, maybe its that nasty inverted dustcap
And you will end with a 90db design, considering BSC
And a cheap Eminence CD on a random waveguide may not work too good either
But i say that without knowing any of those drivers
Fore a nice cheap 8", maybe look at Eminence BETA-8A, and at about the price of B&C you can get two Beta8
Maybe two will really rock
But xo fore compression drivers may not be that easy to handle
As fore the waveguide, there hav been a few suggestions
One was from this company http://www.qscaudio.com/products/accessories/loudspeaker_accessories.htm under replacement parts
And you will end with a 90db design, considering BSC
And a cheap Eminence CD on a random waveguide may not work too good either
But i say that without knowing any of those drivers
Fore a nice cheap 8", maybe look at Eminence BETA-8A, and at about the price of B&C you can get two Beta8
Maybe two will really rock
But xo fore compression drivers may not be that easy to handle
As fore the waveguide, there hav been a few suggestions
One was from this company http://www.qscaudio.com/products/accessories/loudspeaker_accessories.htm under replacement parts
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Maybe the Eminence Beta 8A with the B&C DE10 crossed at 2.5khz with the Dayton 8" ? Iv'e used the Beta 8a in a ported 20-30ltr box before it sounds very good. I crossed it at 2khz into a BMS4540 (MINIRIG » minirig V6). I had issues with the mid-high porting and the phasing with the ported sub though. Now I am running sealed mid-highs using Eminence Beta 10 and a B&C DE10, using the Dayton 10". Much better, easier to blend with the subs.
http://minirig.org.au/2008/11/13/minirig-10-mid-high-with-10-waveguide-and-compression-driver/
col.
http://minirig.org.au/2008/11/13/minirig-10-mid-high-with-10-waveguide-and-compression-driver/
col.
I will also consider the Eminence Beta 8A and B&C DE10. What makes them a better combination than the B&C and Emenence (other than price?).
Will a 12 db/octave crossover around 2500 Hz be a good starting point? Remember, I can adjust phasing to each speaker individually with my Panasonic class D amp.
Will a 12 db/octave crossover around 2500 Hz be a good starting point? Remember, I can adjust phasing to each speaker individually with my Panasonic class D amp.
Hi Tinitus,
Can you say what "cheap" has to do with "technique" (Do you mean is bad?!).
(Having said that) As a good resource for working with the Eminence PSD2002 go look at the work of W.Parham at PiSpeakers (you can buy his xovers too):
Pi Speakers - unmatched quality and state-of-the-art performance
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Thanks for the link - I'm giving his crossover write-up a couple read throughs. Hopefully it will click after a while.
I have the neodymium version of that woofer, and I've done a ton of measurements. It's an exceptional eight, possibly the best I've ever used. IMHO, the response isn't peaking because of the dustcap. The response is peaking because the woofer is beaming. Beaming will occur at a frequency which is equivalent to the piston diameter. For the 8PS21, that's about 2khz.
In an average speaker the inductance in the motor begins rolling off the response of the woofer. But the 8PS21 (and the 8NDL51) has a copper cap to extend the high frequency response.
Combine these two things, and you end up with a rising response above 1khz. This is actually a good thing - it demonstrates that the speakers performance is nearly perfect.
Here's a comparison of the distortion performance of the neo and ferrite versions of the B&C. One was measured by John Krutke and the other by AUgerpro
IMHO, the B&C eights are superior to the Eminence. The eminence is a good buy, but the B&C's price is justified by it's excellent performance.
I would consider BMS, B&C or Celestion for the top end instead of Eminence.
I have the neodymium version of that woofer, and I've done a ton of measurements. It's an exceptional eight, possibly the best I've ever used. IMHO, the response isn't peaking because of the dustcap. The response is peaking because the woofer is beaming. Beaming will occur at a frequency which is equivalent to the piston diameter. For the 8PS21, that's about 2khz.
In an average speaker the inductance in the motor begins rolling off the response of the woofer. But the 8PS21 (and the 8NDL51) has a copper cap to extend the high frequency response.
Combine these two things, and you end up with a rising response above 1khz. This is actually a good thing - it demonstrates that the speakers performance is nearly perfect. The extended response also makes it easier to integrate the B&C with a waveguide.
This is my own personal measurement of the 8NDL51. I didn't calibrate the SPL level (I don't have an SPL meter.) My measurements shows higher distortion than the others because it's done with 10 watts at 10 feet. Look how smooth the response is! Just crazy flat. This graph has 3rd octave smoothing. One of the reasons it's so flat is that it's measured from ten feet away, but increasing the distance makes it easier to get low frequency resolution. I'm not sure why 3rd harmonic looks higher on my measurements. The rolloff at 5khz is due to the sampling rate.
Here's a comparison of the distortion performance of the neo and ferrite versions of the B&C. One was measured by John Krutke and the other by AUgerpro
IMHO, the B&C eights are superior to the Eminence. The eminence is a good buy, but the B&C's price is justified by it's excellent performance.
I would consider BMS, B&C or Celestion for the top end instead of Eminence.
It is based on Waynes(pispeakers) and a few others experiences from an older debate on these CDs
B&C CD was concluded to be a significant upgrade over Eminence
The word "cheap" maybe should not have been used that way, wasnt meant to be
B&C woofer looks way better than the cheap Beta8, sure
I have no problem with a cheap driver, if it sounds good
Cheap compression drivers, may be different matter tho
I suppose 100USD is already cheap as is
Well, response on B&C woofers looks like obvious breakup to me, maybe its not
And I really didnt know "beaming" looked like that
It usually doesnt bother me much
Reason I mention Beta8 is that its known to be good even used "fullrange"
I expect xo point to end up relatively high as is
I have never heard much about the B&C and I have nothing against it
It just didnt look like a woofer I would use high up, or suggest to a "newbie", due to special topend
Sensitivity is avrage, but I guess ok fore 8"
Thats about all there is to it
But if its better than factory suggest, then fine
Its not that I try to argue either
If you dont know about BSC, its a loss in low midrange
If you do not compensate the result will be thin and edgy sound
If you compensate with 3db you will have a 90db speaker
With double woofers in a 2.5way you may get 95db, or more
and more midbass pressure as well
Also note that many high sensitive smaller pro drivers may have even further relative loss of midbass SPL
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+/- 6 db on the Beyma. Beware of the 20 db step graph...
B&C for comparison is in 5 db steps...
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The E-wave highpass is actually 3k electrical, and yields a 1.6k acoustic crossover point. A 12" woofer is recommended as the best directivity match for the waveguide at the crossover point, but many builders have used 10's.
There's also Brandon's No Quarters.
Until recently I would have said no, but my 18Sound ND1090 have surprised me with how good they sound.Can titanium diaphragms ever sound good? I have yet to experience that...
Any conclusions on this design? I'll through in another interesting concept with 8" woofer and waveguide. Measurements are looking excellent also.
18 sound kit
I remember that in a thread, a while ago, Dr. Geddes gave a positive feedback on the way the speaker measured.
18 sound kit
I remember that in a thread, a while ago, Dr. Geddes gave a positive feedback on the way the speaker measured.
Measurements - Patrick
If Patrick Bateman is around, I'd like to ask a question about the measurement graphs of the 8PS21 and 8NDL51 . Were they done at comparable input levels ?
I notice the harmonic distortion measurements from 100Hz to 1000Hz appear to be somewhat better on the ferrite speaker, but I notice also the curves are at different levels on the charts and were done by different people .
Just wondering if Patrick had any background info .
Does anyone know how the surface/cone finish compares between the two and if they are different to the 8PE21 which I like . I want to steer clear of resin/epoxy-coated cones but may need to use one or other of these two drivers, for a horn project ..
I know it's a long-shot to get all this info ;o)
MJ
If Patrick Bateman is around, I'd like to ask a question about the measurement graphs of the 8PS21 and 8NDL51 . Were they done at comparable input levels ?
I notice the harmonic distortion measurements from 100Hz to 1000Hz appear to be somewhat better on the ferrite speaker, but I notice also the curves are at different levels on the charts and were done by different people .
Just wondering if Patrick had any background info .
Does anyone know how the surface/cone finish compares between the two and if they are different to the 8PE21 which I like . I want to steer clear of resin/epoxy-coated cones but may need to use one or other of these two drivers, for a horn project ..
I know it's a long-shot to get all this info ;o)
MJ
Only one of the graphs was mine - the last. The other was from Brandon (augerpro) and John Krutke (Zaphaudio.) Their websites are listed in their sigs.
I don't have an SPL meter, but I did my measurements at a higher power level. So ignore the SPL scale and just focus on how deeply buried the distortion components are.
I think you'll be happy with any of the speakers from B&C really. I have a preference for neo because I like small enclosures, and neo motors are generally underhung, which is known to reduce distortion. B&C doesn't state if the motor is underhung IIRC.
I can't imagine why you'd want an untreated paper cone for a midrange really. Untreated paper cones have that raspy sound at high levels due to cone breakup. The 8NDL51 cone is definitely treated. I can't tell if it's epoxy or PVA, though I'd lean towards the former.
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