Andy,
Thats a good summary. I am working on returning the amplifier and DAC to be able to explore the active option. There is massive restocking fee being slapped on these returns. I guess this is to be expected on these low volume products.
Tweeter change is pretty much confirmed in any case.
Rest of the passive work. I still need to mull a bit on it and also see what 5th element has to say about the latest developments.
My comment regarding the tweeter in relation to the bass was meaning that if the balance was excessively bright it would accentuate the lack of bass. Having that depression in the tweeters response would help in making sure that that wouldn't happen.
Yes but nothing that he mentioned would account for the huge lack of bass and lower midrange.
You can also build a jig that would cost peanuts for LIMP (that comes with the ARTA package) and it will measure crossover components as well as the impedance.
None of this will sort out the huge lack of energy below the mid/tweeter.
This is the biggest issue at the moment, the midrange and tweeter section is running hot by quite a margin compared to the series wired dual bass drivers, this is not a surprise given the configuration as the dual bass drivers in parallel, as per my simulations, is how the speaker needs to be configured for a sensitivity match. I figured that both the mid and tweeter would be padded down significantly to match the woofers, but this may not be the case.
Rick’s suggestions on fixing enclosure volume issues, and padding mid/tweeter down while integrating the 8” well with the subwoofer may get a good level of improvements coupled with fixing the baffle mounting holes.
Not sure if this will address the clarity, resolution issues and imaging issues. And not sure how well the lowered sensitivity will be handles by the 200W stereo amp.
Passive options: New tweeter and mid/tweeter XO, parallel W22 with new XO and in the worst case possibly a new pricey midrange
Wants to start a discussion on the active option.
Yamaha that Derek suggested earlier does seem to be an excellent multichannel option.
What about DSP?
I need USB and COAX inputs, support for 24-bit/192Khz, volume control and external multichannel DAC.
The Yamaha has top of the line ESS sabre 32 9018 on 8 channels. Can the DSP XO be made to work well with the Yamaha.
Yamaha also has some DRC and subwoofer integration options.
Which DSP option suits this requirement? MiniSharc looks good, but needs quite a bit of work to addin usb streaming, IOs and interface to external DAC.
Not sure if this will address the clarity, resolution issues and imaging issues. And not sure how well the lowered sensitivity will be handles by the 200W stereo amp.
Passive options: New tweeter and mid/tweeter XO, parallel W22 with new XO and in the worst case possibly a new pricey midrange
Wants to start a discussion on the active option.
Yamaha that Derek suggested earlier does seem to be an excellent multichannel option.
What about DSP?
I need USB and COAX inputs, support for 24-bit/192Khz, volume control and external multichannel DAC.
The Yamaha has top of the line ESS sabre 32 9018 on 8 channels. Can the DSP XO be made to work well with the Yamaha.
Yamaha also has some DRC and subwoofer integration options.
Which DSP option suits this requirement? MiniSharc looks good, but needs quite a bit of work to addin usb streaming, IOs and interface to external DAC.
Minidsp NanoDigi takes up to 24/192 in/out, can handle stereo 4-channel xo. Puts out digital signal to your favourite multiple/multichannel dacs and amplifiers! Minidsp is well documented and UI is clean, lots of fellow users at various forums that can help you.
I went back and revisited the volume needed for each driver. Each figure is net after bracing and the volume displaced by the driver is already factored in.
W15 - .25 cubic ft.
W22's - 1.5 cubic ft. (total for two drivers)
12" sub - 1.13 cubic ft.
Yes, it does matter what the volumes are because they affect the acoustic transfer functions when combined with the electrical filters. The oversized volumes increase excursion in the lower frequencies and the lower mid / upper bass output will be too lean. In the case of the subwoofer the settings on the amplifier can be adjusted to compensate but reducing the cabinet volume is the better option.
The volume on each section was tested nearfield to verify the acoustic slope and not a simple software simulation. As far as the speculation on whether the 8" drivers should be in parallel instead of series you have to factor in the fact that those drivers are operating in a bandpass filter which has a gain factor affected by the filter points and the electrical transfer function. Making an assumption based on a manufacturer's sensitivity rating is no substitution for testing the actual drivers in the end cabinet with filters in place.
The comment of "there's no baffle step compensation" is perplexing. First of all, if that is the case then I should have a sharp rise in my measurements from 200hz to 1K or so. That's not the case. The step range also falls across three different drivers so it's not as simple to draw conclusions from versus say an ordinary 2-way design. Assuming the in-room measurement is correct (the OP is admittedly new to this) then I suspect a few things:
1) a room response null
2) inaccurate settings on the subwoofer
3) negative impact on the response from the wrong interior volumes for each section
4) wrong polarity on one or more of the drivers
The subwoofer can be calibrated using nearfield measurements with the microphone close to the center of the dustcap (1/2" to 1" is fine - just be sure to not have the volume too high so that the dustcap doesn't hit the microphone. Again, if you don't get the subwoofer properly optimized with the 8" drivers then the balance of the entire speaker will be off target. Given the room you have the tweeter's wide dispersion and coverage of the mid may make it too bright for your taste, especially with source material that's lacking in recording quality. The resistor changes I gave you are fairly inexpensive to implement so after you fix the cabinet issues and calibrate the bass section you can see if you need to make level adjustments.
The imaging issue is more elusive. I can say that I've never had that specific complaint about the RC4 so I'm guessing some of it might be room related. If the frequency balance is off then that can also play a part. This also assumes all of the polarities are correct.
If you change the tweeter / mid levels and still don't like the balance then it would be possible for me to change the voicing with a different passive crossover. You can change the tweeter but of course that would require a new crossover as well. The high pass filter on the 8" drivers can be omitted as Navin did for his system. That would allow you to shift the crossover point lower to the subwoofer if desired. This does change the low pass crossover section for the 8" drivers so you cannot just remove the high pass components.
The active DSP crossover option is beneficial since you can tailor the sound to your preference (within reason) but it won't cure all of your room issues.
W15 - .25 cubic ft.
W22's - 1.5 cubic ft. (total for two drivers)
12" sub - 1.13 cubic ft.
Yes, it does matter what the volumes are because they affect the acoustic transfer functions when combined with the electrical filters. The oversized volumes increase excursion in the lower frequencies and the lower mid / upper bass output will be too lean. In the case of the subwoofer the settings on the amplifier can be adjusted to compensate but reducing the cabinet volume is the better option.
The volume on each section was tested nearfield to verify the acoustic slope and not a simple software simulation. As far as the speculation on whether the 8" drivers should be in parallel instead of series you have to factor in the fact that those drivers are operating in a bandpass filter which has a gain factor affected by the filter points and the electrical transfer function. Making an assumption based on a manufacturer's sensitivity rating is no substitution for testing the actual drivers in the end cabinet with filters in place.
The comment of "there's no baffle step compensation" is perplexing. First of all, if that is the case then I should have a sharp rise in my measurements from 200hz to 1K or so. That's not the case. The step range also falls across three different drivers so it's not as simple to draw conclusions from versus say an ordinary 2-way design. Assuming the in-room measurement is correct (the OP is admittedly new to this) then I suspect a few things:
1) a room response null
2) inaccurate settings on the subwoofer
3) negative impact on the response from the wrong interior volumes for each section
4) wrong polarity on one or more of the drivers
The subwoofer can be calibrated using nearfield measurements with the microphone close to the center of the dustcap (1/2" to 1" is fine - just be sure to not have the volume too high so that the dustcap doesn't hit the microphone. Again, if you don't get the subwoofer properly optimized with the 8" drivers then the balance of the entire speaker will be off target. Given the room you have the tweeter's wide dispersion and coverage of the mid may make it too bright for your taste, especially with source material that's lacking in recording quality. The resistor changes I gave you are fairly inexpensive to implement so after you fix the cabinet issues and calibrate the bass section you can see if you need to make level adjustments.
The imaging issue is more elusive. I can say that I've never had that specific complaint about the RC4 so I'm guessing some of it might be room related. If the frequency balance is off then that can also play a part. This also assumes all of the polarities are correct.
If you change the tweeter / mid levels and still don't like the balance then it would be possible for me to change the voicing with a different passive crossover. You can change the tweeter but of course that would require a new crossover as well. The high pass filter on the 8" drivers can be omitted as Navin did for his system. That would allow you to shift the crossover point lower to the subwoofer if desired. This does change the low pass crossover section for the 8" drivers so you cannot just remove the high pass components.
The active DSP crossover option is beneficial since you can tailor the sound to your preference (within reason) but it won't cure all of your room issues.
Last edited:
Rick,
I do suspect room modes as i have mentioned before.
But there are other aspects which are not entirely explained by room issues.
I observe the distortion, straining, lack of resolution on even some high resolution track samples as well as good quality original CDs, the music just has to be complex with several instruments and vocals and fast rhythm all occurring at the same time. Could be the ribbon sound that i am not used to.
Hence my willingness to try out a dome tweeter and hence a new mid/high XO. But i understand that cant happen in isolation and has to be blended right with the woofer XO.
As i mentioned, I am first going to follow the steps you have listed out before attempting big changes.
Whats your view on the lowered sensitivity with mid/tweeter padding?
thanks
Joji
Last edited:
Thanks for digging up the volumes. I will check them out more accurately tonight and report back.
Just as a data point i want to list U2 'Elevation' from 'All That You Can't Leave Behind'.
This one almost always sounds like harsh bad quality recording, a sound wall if you will.
But i have heard them play beautifully on a couple of occasions.
But as i have said before, some slow male vocal tracks, jazz, blues, even classical, instrumentals sound amazing to very good on these speakers
This one almost always sounds like harsh bad quality recording, a sound wall if you will.
But i have heard them play beautifully on a couple of occasions.
But as i have said before, some slow male vocal tracks, jazz, blues, even classical, instrumentals sound amazing to very good on these speakers
Hi Jojip,
I may be wrong, but after analyzing your measurements carefully I came to the conclusion that there must be a wrong capacitor in your crossover. I'm speaking of the first capacitor in the midrange section. My original guess was 82 uF, but it could be 68 uF as well. However, your measurements indicate an actual value of 33 uF, which is far too little and results is a dip in the frequency response at 300-400 Hz and a peak at 1 kHz. Hence the speaker sounds bright and makes you think the woofers do not work properly.
Just my two cents. 🙂
I may be wrong, but after analyzing your measurements carefully I came to the conclusion that there must be a wrong capacitor in your crossover. I'm speaking of the first capacitor in the midrange section. My original guess was 82 uF, but it could be 68 uF as well. However, your measurements indicate an actual value of 33 uF, which is far too little and results is a dip in the frequency response at 300-400 Hz and a peak at 1 kHz. Hence the speaker sounds bright and makes you think the woofers do not work properly.
Just my two cents. 🙂
Individual driver roll offs from too much cabinet volume will lower the output a little, but by nothing significant. We're talking gross issues here. Yes oversized cabinets will create a 'lean' balance but this going to be minor, especially if a sub was supposed to augment the lower end.
If you look at the individual measurements for each driver in jojip's loudspeaker you will see that both the midrange and the woofers roll off to result in a crossover around 500Hz. A larger cap on the midrange would result in a greater amount of output into the area in which the loudspeaker is lacking, but it's not the answer imo.
If you look at the individual measurements for each driver in jojip's loudspeaker you will see that both the midrange and the woofers roll off to result in a crossover around 500Hz. A larger cap on the midrange would result in a greater amount of output into the area in which the loudspeaker is lacking, but it's not the answer imo.
"In a vision I saw removing the four lo-tech Peerless subwoofers 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 sensitivity for two in series(93db for 3.5-ohm parallel load). Replace the ribbon with a dome tweeter using LR4 @2Khz to the W15CY-001 (E0015) after chopping open the front baffle tunnel into 0.25cuft fiberglass-lined volume Qtc =0.57 F3= 66Hz 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."
Sadly, my prayers for audio jubilation and exultation could not be answered. .... but I found great organic Kale at Whole Foods.
Two hi-tech Seas W22EX001 8" woofers will provide detailed midbass plus strong ported alignment bass down to F3~29Hz. 5th Element's sims in post #117 prove solid bass plus good baffle step comp is possible from the two W22 midbass.
"Precision cast and surface treated magnesium cone coupled to a natural rubber surround showing no sign of midrange (edge) resonances. Heavy copper rings mounted above and below the T-shaped pole piece reduce non linear and modulation distortion and increase overload margin. Extremely stiff and stable injection molded metal basket keeps the critical components in perfect alignment. Large windows in the basket both above and below the spider reduce sound reflection, air flow noise and cavity resonance to a minimum. A solid copper phase plug enhances the performance of the copper rings and improves heat conduction away from the pole piece."
The Peerless 830844 is a lo-tech subwoofer. Qtc=0.2 and Fs=17Hz requires extensive boost and high watts to generate 20-30Hz bass. Heavy 176g cone, Le=4.2mH, probably best to use these in separate subwoofer boxes with Xover below 60Hz, instead of 90Hz used in this speaker.
There is a version of this design without the subs.
Sadly, my prayers for audio jubilation and exultation could not be answered. .... but I found great organic Kale at Whole Foods.
Two hi-tech Seas W22EX001 8" woofers will provide detailed midbass plus strong ported alignment bass down to F3~29Hz. 5th Element's sims in post #117 prove solid bass plus good baffle step comp is possible from the two W22 midbass.
"Precision cast and surface treated magnesium cone coupled to a natural rubber surround showing no sign of midrange (edge) resonances. Heavy copper rings mounted above and below the T-shaped pole piece reduce non linear and modulation distortion and increase overload margin. Extremely stiff and stable injection molded metal basket keeps the critical components in perfect alignment. Large windows in the basket both above and below the spider reduce sound reflection, air flow noise and cavity resonance to a minimum. A solid copper phase plug enhances the performance of the copper rings and improves heat conduction away from the pole piece."
The Peerless 830844 is a lo-tech subwoofer. Qtc=0.2 and Fs=17Hz requires extensive boost and high watts to generate 20-30Hz bass. Heavy 176g cone, Le=4.2mH, probably best to use these in separate subwoofer boxes with Xover below 60Hz, instead of 90Hz used in this speaker.
There is a version of this design without the subs.
Attachments
The XLS drivers are not low tech, they have large linear excursion that isn't suspension limited and advanced motors with shorting rings and low distortion. They have a low qts because of theIr extremely powerful motor. This has been done by design to result in an EBS alignment when used in a small box with a suitable passive radiator, giving 20Hz extension in a small box with high SPL capabilities. If you want to use them in a sealed box then they need EQ to get there, but this doesn't make them low-tech, pretty much all sealed subs work like this.
Also need USB streaming to play PC music. Basically all my sources have to go through the DSP. The Yamaha is only going to play the role of DAC and power amplifier.
Anyone familiar with the Yamaha please comment if it can take multi channel digital inputs to drive the DACs. I see only 3 coaxial digital inputs.
Thanks for that observation, but the same value seems to be used on both the boards so does seem like an unlikely error.
Will measure the value of the cap at some point.
Most definitely is that 2 woofer drivers in series should be
loud enough for about 87 dB with filter on. So I have simulated
based on a box 11" by 43", with the woofers in one sealed 44 liter box.
With a few passive parts in stock, a little bit of measuring, simulating
and the issue is gone in a couple of hours.
loud enough for about 87 dB with filter on. So I have simulated
based on a box 11" by 43", with the woofers in one sealed 44 liter box.
With a few passive parts in stock, a little bit of measuring, simulating
and the issue is gone in a couple of hours.
I agree. I often run my system (same woofers and mid) with the subwoofers turned off as most of the music I listen to has little below 40Hz anyway. In 2 channel mode driven by a measly 90W amp it more than satisfies in a 30x14x9.5' room. My listening position is about 1/3 from the back wall which in reality is a wide window (the entire width of the room).
It may well be the difference between my room and Jojip's (I have a marble floor over 4" RCC slab and brick walls) but I would also assume much of the differences is in the cabinet (oversized, 3" baffle, etc..).
Exactly. But the EQ or the PR would only affect the low bass right? Would this improve the mid-bass 'slam' or 'punch' which seems to be Jojip's speaker seems to be missing?
Joji,
the easiest way of measuring RLC values appears to be through ARTA labs
impedance measurement package. Try looking for a jig on arta's web, I know
I have seen it.
the easiest way of measuring RLC values appears to be through ARTA labs
impedance measurement package. Try looking for a jig on arta's web, I know
I have seen it.
How about a vison of using Peerless units for multiple subs and the main
pair of speakers wired as 3 way without woofer HP? I presume at least one
person (Greebster) would be in favor of it.
^^Me too.
Subwoofer holes should be filled with passive radiators, inside divider perforated, the volume would be opimal for BR. Perhaps .5 configuration for BSC.
Baffle modifed to give the mid more air. With active xo or new passive xo this would be optimal. The excellent (X)XLS woofers make good BR-subs in moderately sized boxes.
Subwoofer holes should be filled with passive radiators, inside divider perforated, the volume would be opimal for BR. Perhaps .5 configuration for BSC.
Baffle modifed to give the mid more air. With active xo or new passive xo this would be optimal. The excellent (X)XLS woofers make good BR-subs in moderately sized boxes.
- Status
- Not open for further replies.