Want to summarize the measurements to make. Please clarify and add.
All measurements without the subs setup.
1. Measure each individual driver in the enclosure with the crossover.
2. Frequency response plots
3. Distortion
4. Is Impedance needed? (Dont have the setup for that yet)
Questions:
1. In room measurements should be ok?
2. Not sure how to get useful low freq measurement in room. Please advice
All measurements without the subs setup.
1. Measure each individual driver in the enclosure with the crossover.
2. Frequency response plots
3. Distortion
4. Is Impedance needed? (Dont have the setup for that yet)
Questions:
1. In room measurements should be ok?
2. Not sure how to get useful low freq measurement in room. Please advice
That would be unusual for a pair of 8 ohm woofers. If the crossover was designed for the woofers to be in parallel then an incorrect series connection would give about 6dB less woofer output. Might be worth checking.
Gated in room measurements are normally fine for >500 Hz or so. This should sort out the mid/tweeter issues.
Low frequency measurements need to be taken close to the drivers. So called near field measurements. These will not necessarily line up with what is seen in the far field but should be fine for sorting out mid and woofer levels and estimating "baffle step correction".
Danny,
There does appear to be problems with the speaker itself.
But i am very concerned with your observation. Will try to listen with another amplifier, though not sure if i can borrow high end gear easily.
This amplifier is fairly well made. two large torroidal transformers, 30K uf capacitance per channel, and good spec and design information. they cost 2000USD, i will be sorely disappointed if the company is handing out gear that sounds like crap at that price point. And i will be really surprised if a 10000USD price point needs to be reached to get amplifiers that can make fast rock music sound good.
In any case if the ampliifier is a real suspect then i am going to have the company accept a return, as i find a poor performing amplifier at this price unacceptable.
However my only realistic alternative is a Rotel 200W. any opinion on that?
The Yulong DAC preamplifier are designed and made in china, however i understand the space fairly well and i think it is a well designed equipment. Though i am not sure if loading it as a pre amp for a bi-amp/tri-amp setup is the target application for best performance. Do the output stages of these devices hold up well to this application in your view?
The fountek is IMPOSSIBLE, in my opinion, to integrate properly with the W15. For large three way designs I'd want to cross the fountek over at 5-6kHz so that it'd have the ability to play loud without any trouble. The W15 literally requires a crossover no higher than 2.5kHz to work adequately. I've used this driver extensively myself and to get the best out of it you really do need to xover it more around the 2kHz mark. We're wanting no compromise right? Well it needs to be crossed that low.
2. The 8" woofers are not wimpy, they are pretty great in and off themselves. Regardless of the design choices this loudspeaker will have plenty of bass between the W22s and the 10" XLS drivers.
3. As per your pictures of the cabinet, yes the mid range drivers baffle cut out needs chamfers. Why anyone would go with a baffle that thick I do not know it is completely unnecessary and makes lot of other things a lot harder. The designer should really have gone for the W15CH001s with this motor structure to allow the cone to breath more.
All the design really needs to make it sing is...
1) A replacement tweeter, such as the T25CF001, which will fit into the 110mm cut out.
2) Chamfering on the midrange baffle cut out.
3) A 2kHz crossover with 4th order acoustic slopes between the tweeter and the midrange.
4) A crossover on the midrange to bass drivers that soaks all of the baffle step losses within the bass drivers. You need to maximise the sensitivity of the midrange driver to ensure a good sensitivity match. Given the width of the cabinet you can probably cross around 300Hz to good effect. You may need to raise the Q of the midrange high pass to compensate for a smidgen off baffle step losses on its low end. Band pass gain on the midrange and insertion losses from the woofer crossover will make up for the slight difference in net sensitivities between the bass and mid range drivers.
5) Blend the sub modules to the W22s like you would a normal sub using the inbuilt plate amplifiers.
A good crossover design will be 100% necessary in making these sound amazing, but all things considered I don't think what you paid for them is a waste at all. Hopefully you'll be able to reuse some of the xover components.
jojip,
I prayed on your challenges in Church this Sunday. In a vision I saw removing the four Peerless woofers for a future project, replacing their holes with ports for the two W22EX-001 (E0022) in 3.8cuft, the two 3"Dia 9.8" long ports tuned to F3= 29Hz SPL=90db for two(93db for 3-ohm parallel load).
Replace the ribbon with a dome tweeter using LR4 @2.2Khz to the W15CY-001 (E0015) after chopping open the front baffle tunnel into 0.15cuft fiberglass-lined volume Qtc =0.7 F3= 81Hz SPL=84.5db, acoustic. L-R-C filter on W15CY to remove cone breakups starting at 5Khz, plus LR4 at 300Hz to woofers. W22EX-001 acoustic LR4 Xovers at 300Hz + some baffle step comp.
SEAS Magnesium - sound best when run over their narrow flat BW with at least acoustic 4th order Xovers
The Magnesium cones have nasty breakups which are very difficult to completely remove with a normal crossover. add LRC traps
All undamped vibrations within the cabinet will easily move through the Magnesium cone and garble the sound the listener hears. Line the volumes with fiberglass.
W15CY-001 (E0015) 0.15cuft Qtc =0.7 F3= 81Hz SPL=84.5db for one
W22EX-001 (E0022) 2.1cuft Qtc =0.7 F3= 54Hz SPL=90db for two
W22EX-001 (E0022) 3.8cuft ported F3= 29Hz SPL=90db for two. 93db at 4-ohm parallel load
God moves in mysterious ways.
Amen
I prayed on your challenges in Church this Sunday. In a vision I saw removing the four Peerless woofers for a future project, replacing their holes with ports for the two W22EX-001 (E0022) in 3.8cuft, the two 3"Dia 9.8" long ports tuned to F3= 29Hz SPL=90db for two(93db for 3-ohm parallel load).
Replace the ribbon with a dome tweeter using LR4 @2.2Khz to the W15CY-001 (E0015) after chopping open the front baffle tunnel into 0.15cuft fiberglass-lined volume Qtc =0.7 F3= 81Hz SPL=84.5db, acoustic. L-R-C filter on W15CY to remove cone breakups starting at 5Khz, plus LR4 at 300Hz to woofers. W22EX-001 acoustic LR4 Xovers at 300Hz + some baffle step comp.
SEAS Magnesium - sound best when run over their narrow flat BW with at least acoustic 4th order Xovers
The Magnesium cones have nasty breakups which are very difficult to completely remove with a normal crossover. add LRC traps
All undamped vibrations within the cabinet will easily move through the Magnesium cone and garble the sound the listener hears. Line the volumes with fiberglass.
W15CY-001 (E0015) 0.15cuft Qtc =0.7 F3= 81Hz SPL=84.5db for one
W22EX-001 (E0022) 2.1cuft Qtc =0.7 F3= 54Hz SPL=90db for two
W22EX-001 (E0022) 3.8cuft ported F3= 29Hz SPL=90db for two. 93db at 4-ohm parallel load
God moves in mysterious ways.
Amen
Attachments
If someone gave me these speakers, I'd pull out the drivers and throw away the cabinets. A 3 inch thick front is a joke. Speakers don't need to weigh any where near that much to be great. The 3 inch cavity effect will damage the FR (frequency response) of the midrange driver, which can only be used up to about 2kHZ with a 4 pole crossover filter, due to its approx. 10dB resonance at around 8kHZ. The Fountek 3 inch ribbon (which I had) is too directional on the vertical axis. I'd instead use a Seas 1 inch Millenium dome (or equiv.) crossed at about 2kHZ with a 4 pole crossover slope. I'd definitely throw away the passive crossover and design and build an active crossover. Calibrating a passive crossover correctly is very challenging (impedance of drivers varies significantly over frequency - the nominal rating is rarely good enough). If it needs to have steep rolloffs (and it does with hard cone drivers), it's extremely challenging. I'd rebuild the cabinet with 3/4 inch MDF, braced strategically with 3/4 X 1 inch oak. The mid driver of coarse needs its own chamber. Glue acousticallyabsorbative material tight to all internal surfaces, then put loose stuffing in much of the rest of the midrange sub-enclosure. This is VERY important. And no two internal dimensions should be the same, or have a 2:1 relationship.
I'd add some active EQ to the woofer signal so there is an electrical 10dB peak at 35HZ, with a quick rolloff below that. I'd calibrate the whole thing with pink noise and a cal'd mic going into a real time analyzer that has at least 1/3 octave frequency resolution, with the mic where my listening position would be. I know that flat is a good default for design, but definitely have a four section Baxandall tone control circuit in my preamp, so I could make it sound much better in my room and to my ears, despite what the recording engineers have created.
With hard cone drivers, there is always a very bad effective resonance somewhere in the upper midrange, right where the ear is very sensitive. Hard cone drivers have better "resolution" but they need a crossover that has very steep rolloffs, in order to get rid of these resonances. Otherwise their usable bandwidth is pretty small. Seas drivers are pretty excellent, but no speaker system is any better than it's weakest link.
The reason the 8 inch drivers seem to put out very little bass is part because they are in a sealed cabinet with no EQ to pump up their low end, part because they only have so much cone surface area for your tall room, and maybe mostly because they don't have much of a surrounding baffle or wall to help reinforce projection of the lowest frequencies into the room (Baffle step issue).
My system, which is open baffle satalites and triamp'd, has the 12 inch woofers in separate cabinets, so I can put them against the front wall at the floor. That 2 surface corner helps projection of the low bass quite a bit. Since bass is very non-directional, I can't really tell that the bass is coming from a slightly different location. From 100HZ to 1.4kHZ I have a vertical array of four 5 inch drivers per side (open baffle), and above that I've got the Seas Millenium 1 inch dome tweeter. Seas makes another 1 inch dome tweeter that is much cheaper than the Millenium, which is probably plenty good. I don't remember the part number. Hope this helps.
I'd add some active EQ to the woofer signal so there is an electrical 10dB peak at 35HZ, with a quick rolloff below that. I'd calibrate the whole thing with pink noise and a cal'd mic going into a real time analyzer that has at least 1/3 octave frequency resolution, with the mic where my listening position would be. I know that flat is a good default for design, but definitely have a four section Baxandall tone control circuit in my preamp, so I could make it sound much better in my room and to my ears, despite what the recording engineers have created.
With hard cone drivers, there is always a very bad effective resonance somewhere in the upper midrange, right where the ear is very sensitive. Hard cone drivers have better "resolution" but they need a crossover that has very steep rolloffs, in order to get rid of these resonances. Otherwise their usable bandwidth is pretty small. Seas drivers are pretty excellent, but no speaker system is any better than it's weakest link.
The reason the 8 inch drivers seem to put out very little bass is part because they are in a sealed cabinet with no EQ to pump up their low end, part because they only have so much cone surface area for your tall room, and maybe mostly because they don't have much of a surrounding baffle or wall to help reinforce projection of the lowest frequencies into the room (Baffle step issue).
My system, which is open baffle satalites and triamp'd, has the 12 inch woofers in separate cabinets, so I can put them against the front wall at the floor. That 2 surface corner helps projection of the low bass quite a bit. Since bass is very non-directional, I can't really tell that the bass is coming from a slightly different location. From 100HZ to 1.4kHZ I have a vertical array of four 5 inch drivers per side (open baffle), and above that I've got the Seas Millenium 1 inch dome tweeter. Seas makes another 1 inch dome tweeter that is much cheaper than the Millenium, which is probably plenty good. I don't remember the part number. Hope this helps.
Last edited:
Based on the pictures of the crossover boards and the impedance plot I tried to estimate the current crossover. It's just a guess, but hopefully good enough to answer some basic questions. 
The woofers do not play below 100 Hz because they are high-pass filtered. As Lojzek already mentioned, the frequency response shows a peak below 200 Hz. Two 8" woofers costing a fortune just to play from 80 to 300 Hz does not make much sense IMO.
The midrange covers the range from 300 Hz to 4 kHz. The crossover to the ribbon and the tweeter level may not be perfect, but that doesn't explain why the speaker sounds so disappointing. Either it's the mounting issue or the midrange simply is wired in wrong polarity. The lack of sound stage is a typical sign for wrong polarity too, so check that out carefully!
Ribbon tweeters are known to have high distortions, but some people like them anyway. My advise is to keep the ribbons and to fix the major issues of the speaker first. Then you still can decide on their destiny.
The woofers do not play below 100 Hz because they are high-pass filtered. As Lojzek already mentioned, the frequency response shows a peak below 200 Hz. Two 8" woofers costing a fortune just to play from 80 to 300 Hz does not make much sense IMO.
The midrange covers the range from 300 Hz to 4 kHz. The crossover to the ribbon and the tweeter level may not be perfect, but that doesn't explain why the speaker sounds so disappointing. Either it's the mounting issue or the midrange simply is wired in wrong polarity. The lack of sound stage is a typical sign for wrong polarity too, so check that out carefully!
Ribbon tweeters are known to have high distortions, but some people like them anyway. My advise is to keep the ribbons and to fix the major issues of the speaker first. Then you still can decide on their destiny.
Attachments
Based on the pictures of the crossover boards and the impedance plot I tried to estimate the current crossover. It's just a guess, but hopefully good enough to answer some basic questions.
The woofers do not play below 100 Hz because they are high-pass filtered. As Lojzek already mentioned, the frequency response shows a peak below 200 Hz. Two 8" woofers costing a fortune just to play from 80 to 300 Hz does not make much sense IMO.
The midrange covers the range from 300 Hz to 4 kHz. The crossover to the ribbon and the tweeter level may not be perfect, but that doesn't explain why the speaker sounds so disappointing. Either it's the mounting issue or the midrange simply is wired in wrong polarity. The lack of sound stage is a typical sign for wrong polarity too, so check that out carefully!
Ribbon tweeters are known to have high distortions, but some people like them anyway. My advise is to keep the ribbons and to fix the major issues of the speaker first. Then you still can decide on their destiny.
Excellent inputs. Thanks for taking the time.
The information i had from the designer was that the 8"woofers are down -3db at 60Hz.
The first thing to do is find out what you have got and where the problems lie. Opening out the holes should bring improvements but I doubt it will address the large issues you are reporting. Perhaps there are gross errors like incorrect wiring but if not then I think you may be stuffed if you do not want to pickup the task of modifying the crossover possibly in conjunction with other changes like an appropriate tweeter for the midrange.
Based on the pictures of the crossover boards and the impedance plot I tried to estimate the current crossover. It's just a guess, but hopefully good enough to answer some basic questions.
The woofers do not play below 100 Hz because they are high-pass filtered. As Lojzek already mentioned, the frequency response shows a peak below 200 Hz. Two 8" woofers costing a fortune just to play from 80 to 300 Hz does not make much sense IMO.
The midrange covers the range from 300 Hz to 4 kHz. The crossover to the ribbon and the tweeter level may not be perfect, but that doesn't explain why the speaker sounds so disappointing. Either it's the mounting issue or the midrange simply is wired in wrong polarity. The lack of sound stage is a typical sign for wrong polarity too, so check that out carefully!
Ribbon tweeters are known to have high distortions, but some people like them anyway. My advise is to keep the ribbons and to fix the major issues of the speaker first. Then you still can decide on their destiny.
Good evening Jojip, I just bumped into this thread (as I am not very active on diyaudio). I believe these speakers are from Selah Audio (Rick Craig). In all my interactions with Rick, I have found him to a reasonable gent, and I would address him as he might have the best answers to some of your challenges.
After all his has pictured your speaker (towards the bottom of his DIY page)
DIY ? Selah Audio
http://static1.squarespace.com/stat...d/1406777673664/RC4CurvedBack.jpg?format=500w
Now back to some of the challenges.
1. As far as the tweeter is concerned I would consider the NeoX tweeters from Fountek as they share the same mounting plate and can be crossed low and do not need high order XOs (they have lower distortion than the NeoCD series).
Products_Fountek Electronics Co.,Ltd
Products_Fountek Electronics Co.,Ltd
I say this because I too have built similar speakers (see link below) and also rear speakers using the NeoCD3.0 tweeter with the Seas W16NX woofer.
see link
Pictures of Selah designed Tempesta Extreme and RC4 (no subwoofer)
The Yung SD500 amps died and I have since replaced them with Kiega KG ND-52100-SP amplifiers. Another choice could the Hypex. I use a Yamaha S2000 for the main speakers (8" 3 way).
2. That tube behind the mid might be causing some issues but I cannot see these be as severe as you describe. Did you check the polarity of the tweeters?
3. Before getting the Selah audio I auditioned many speakers like the B&W CM8, KEF R700, Focal 836W, Paradigm Studio 100, Monitor Audio GX300, etc... and none of them satisfied. So I went back to the drawing board and looked at speakers that had satisfied me in the past - Sonus Faber Cremona, Vandersteen 4A, Martin Logan Sequel, Klipsch's Belle Klipsch and Klipschorn combo, Wilson Audio Sophia, Tannoy DC10T ... and I could not afford any, not even used (Audiogon). Speaking of Audiogon a seller called Solstice (or something like that) had a pair of these on sale some moons ago - cant remember when.
I am not putting Selah's creations in the same league as the later list, but they are at least equal to the former list, and they get there at roughly half the price (even less in my case as I built the cabinets locally hence did not pay freight, duties and taxes on the cabinets). This is the thread I had some years ago http://www.diyaudio.com/forums/multi-way/208311-selah-audio-ex-diyer.html
So 2 pointers:
Ribbons by nature are more directional on the vertical axis but I find that when seated this is not a huge issue. The horizontal axis is more critical.
The hard cones (Mg) of the SEAS drivers are very good within their pass band and terrible outside it. Bob Richards has already said this. If the crossover posted by Dissi is correct then the 15cm mid might be your culprit. It's electrical slope is too high for a hard cone (and even combined with the roll of the of the midrange itself) and maybe a lower crossover point combined with a tweeter that can go low enough may be a place to start. Troel's small monitor uses this woofer W15CY001-OWI
Make 1 change at a time so you can tell the effects of the change.
Best of luck.
I am using Jeff Bagby's set of simulation spreadsheets.
These are capable of simulating cabinet volumes and their
FR responses in bass region ( Woofer box and Circuit designer),
then there is PCD for simulating XO filters and Response Modeler
to manipulate response curves by adding baffle step response
and merging curves.
In its nature these crunching numbers software are accurate if the
input data is accurate as well. Input data in my case were manufacturer's
measurements of FR and impedance which I obtained by using SPL Tools,
a program that turns pictured graphs into textual files ( frd and zma)
which can be loaded to any simulator.
With additional data on acoustic centres of the drivers in the baffle and
their position, it can be observed how the performance changes over
different angles ( listening position).
My simulation is only accurate sufficiently to have a taste what one might
expect. For better accuracy, measurements of the real drivers in the real
box are mandatory.
Squeeze the last drops of juice these units can give you before you decide
to open your wallet again.
Personally, I would modify this speaker of yours to be a 3 way box with 22EX's
in series filtered passively at 300 Hz and somewhere around 3,5-4 kHz.
The inner volume for the woofers should be in the range of 100 liters vented
to properly play bass notes.
There is always the learning curve whatever you do. Maybe you will consider
to get rid of the speakers and try an alternate route.
That is good find. The OP would seem to have a speaker made from a Selah RC4 kit but using an odd baffle. Is half the lower woofer blocked by the subwoofer enclosure in the paper design?
Having googled Selah RC4 I see this version has avoided using the ribbon tweeter. In your version I see you have dropped the subwoofer. Have you ported the woofers, kept them sealed in a larger chamber, or perhaps something else?
Several posters including myself have doubts about the combination of a large metal midrange and a small ribbon tweeter in a 3 way with significant output from decent sized woofers. Are you happy with this aspect of your speakers?
I know the original designer of the speakers. I didn't wish to bring up the name on this thread, as this is not really meant to be a judgement of his designs or products. From what i understand his products are pretty good and popular.
This particular implementation has significantly deviated from his spec and there are sources of problems we are trying to address here.
I bought these used from a third person. I had communicated with the designer and he was helpful enough to pass the plots to me.
In any case, would be great if we can keep the designer's business out of the discussion.
This particular implementation has significantly deviated from his spec and there are sources of problems we are trying to address here.
I bought these used from a third person. I had communicated with the designer and he was helpful enough to pass the plots to me.
In any case, would be great if we can keep the designer's business out of the discussion.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.