Chris ran A6.2MeN rears (3.5”). The 5” CHR-90 should be fine in the front. Chris
You aren’t going to be able to go full THX but i know few who listen that loud.
dave
Plugged in the SB20 into HornResp. I have nothing against WinISD, it was great, but it is getting a bit outdated. The same physics apply, of course, but the tools and simulation packages have improved since then.
HornResp is very well supported and upgraded all the time. Very worth having a look at it.
Here is a sealed 25-liter SB20 running at 13W, reaching displacement of about 5mm at about 50Hz, and 110dB. F3 at about 65Hz.
I seriously doubt you will listen to movies at 95dB for an extended period of time, yet alone 110dB!
Plus, since you will have subs starting to fill in at 80Hz, you can cut the SB20 before it reaches Xmax, rendering this issue non-existent.
HornResp is very well supported and upgraded all the time. Very worth having a look at it.
Here is a sealed 25-liter SB20 running at 13W, reaching displacement of about 5mm at about 50Hz, and 110dB. F3 at about 65Hz.
I seriously doubt you will listen to movies at 95dB for an extended period of time, yet alone 110dB!
Plus, since you will have subs starting to fill in at 80Hz, you can cut the SB20 before it reaches Xmax, rendering this issue non-existent.
Attachments
I too am a fan of 8" full range drivers.
Honestly, a few watts in the low 100's and the voice will garble big time.
But movies can have much voice or boom, but not both at the same time, such as in music.
I would not be concerned about xmax much, just roll them off at the front.
Maybe even 100hz if you can.
I can't speak for the sb20, but my 1808 and 2145, listening area at 7' was 1 head.
At 12', they can do 2 heads if the peoples' shoulders are touching........
The 1772 is said to have better dispersion than most 8" whizzereds, but then you need a bunch of mid/treble cut to balance the climbing response.
Honestly, a few watts in the low 100's and the voice will garble big time.
But movies can have much voice or boom, but not both at the same time, such as in music.
I would not be concerned about xmax much, just roll them off at the front.
Maybe even 100hz if you can.
I can't speak for the sb20, but my 1808 and 2145, listening area at 7' was 1 head.
At 12', they can do 2 heads if the peoples' shoulders are touching........
The 1772 is said to have better dispersion than most 8" whizzereds, but then you need a bunch of mid/treble cut to balance the climbing response.
Thanks I will take a look
Wow that is very different than what winisd provides... 🙂
I assume those are at 1m right?
Absolutely! The goal is to aim for average 75-80db at listening position (so between 3m and 4m for LCR), with peaks at 95db. This is where the 95db comes from. I have no interest in premature hearing loss.
Yes, this is definitely the plan and was already ignoring going past xmax below 80Hz.
This is exactly my concern with going with a larger cone size, hence why I was looking for smallest driver possible to reach my SPL levels. Though I don't know if this necessarily help, but various measurements I have seen around seem to correlate cone size, frequency at which beaming start, and HF dispersion angles.
Thanks. I guess it depends on listening distance right? rears are typically close to listener whereas fronts are typically farther for home theater (in general because of screen viewing angle). But from the Winisd simulation, the CHR-90 seems right on the edge with 93dB above 100Hz and 89 dB at 80Hz. Do you think it should be fine for an 80-100Hz crossover? Also, would you have feedback on off-axis behavior of CHR-90 (I have not found much data on that online)?
Exactly no plan to go for a THX certification here 🙂 . Just clean sound that can be enjoyed by more than 1 person.
I believe THX reference level is 85dB for each speaker, and 105dB peak at listening position (20dB headroom). For subs this goes to 95dB reference and 115dB peak (equal-loudness contour might have something to do with that).
The 95db peak target I was shooting for was mostly 75db reference with 20db headroom.
Have a look at @nandappe 's YT links with in-room driver demos. I actually got a pair of CHP-90s in large part because of the beautiful mellow tone to my ears (through a pair of decent headphones etc, so cross fingers they won't disappoint IRL.)
I've barely started the build but here are a few early thoughts on unboxing:
The magnet is not ventilated, so they may be prone to a bit of wind noise above a couple mm displacement in the bass. IME the MA. range is, how should I put it... like an oasis of civility.
The CHP-90 suspension stiffness seems quite soft to the touch, but not extremely delicate, and the cone is also light and flexible. Based on that, for sealed enclosures I would give them a soft air cushion by going oversized, maybe 12 or 15 L or even higher, instead of a calculated 7.5L @ 0.707 Qtc. I say go nuts and use the wall space if you can.
I'm using 10mm hardwood ply for my build. It won't need bracing because of the geometry, but for a wide flat design you could have T or I-beams aligned so they are radiating lengthwise out from the driver. Transmission lines could also be very interesting, but you would have your work cut out, so don't do that unless you really don't have enough on your plate.
I've barely started the build but here are a few early thoughts on unboxing:
The magnet is not ventilated, so they may be prone to a bit of wind noise above a couple mm displacement in the bass. IME the MA. range is, how should I put it... like an oasis of civility.
The CHP-90 suspension stiffness seems quite soft to the touch, but not extremely delicate, and the cone is also light and flexible. Based on that, for sealed enclosures I would give them a soft air cushion by going oversized, maybe 12 or 15 L or even higher, instead of a calculated 7.5L @ 0.707 Qtc. I say go nuts and use the wall space if you can.
I'm using 10mm hardwood ply for my build. It won't need bracing because of the geometry, but for a wide flat design you could have T or I-beams aligned so they are radiating lengthwise out from the driver. Transmission lines could also be very interesting, but you would have your work cut out, so don't do that unless you really don't have enough on your plate.
Thanks, Yes I listened to some of those playlists (e.g. CHR-90, CHR-70). I guess it helps to have a sense of what the driver is capable of, but I don't know how that would translate to my usage since the enclosure, room, speaker placement, listening position, SPL ... will be different. I guess it was enough to get me to try to build a speaker 🙂
Regarding your build, let us know how this goes, I am very interested in this!
Regarding your build, let us know how this goes, I am very interested in this!
It is interesting to see that CHP-90 users seem to pick up a tonality difference with CHR-90 when their on-axis published FR are so similar (attached overlay of FR, green is CHP-90, blue is CHR-90). What makes the CHP-90 to be preferred by a number of members of the forum? Is it:
- the dip at 3-4K on the CHR-90 (blue "circle")?
- the CHR-90 bump at 10K (yellow)?
- or is it the above 15K drop of the CHP-90 (red circle) ?
- or are there other differences between the two (e.g. off-axis response, resonances, ...)?
Frequency response plots are a false trail. They will tell you the basic Eq settings, but sometimes the importance is inversely proportional to what you see and it's like reading tea leaves.
Take a metallic resonance as an example. The longer it rings and basically the worse it is, the smaller it looks because it takes up almost no pixels in screen width! The height only gives you the average energy level, and says nothing about when it when it occurs, which could be a factor in how prominent the ringing is.
The CHR and CHP look like they have different cone profiles. The CHR cone looks a bit flatter with a longer voice coil tube, while the CHP cone looks a bit deeper. That, and I just wanted a paper cone for a change, and now you know everything.
If you ruffle a piece of thin cardboard in the air, and do the same with metal foil, the 'crinkling' will just sound different in both cases. Very low-tech, but maybe some of those differences can carry over to the end product.
Take a metallic resonance as an example. The longer it rings and basically the worse it is, the smaller it looks because it takes up almost no pixels in screen width! The height only gives you the average energy level, and says nothing about when it when it occurs, which could be a factor in how prominent the ringing is.
The CHR and CHP look like they have different cone profiles. The CHR cone looks a bit flatter with a longer voice coil tube, while the CHP cone looks a bit deeper. That, and I just wanted a paper cone for a change, and now you know everything.
If you ruffle a piece of thin cardboard in the air, and do the same with metal foil, the 'crinkling' will just sound different in both cases. Very low-tech, but maybe some of those differences can carry over to the end product.
Samba MT should fit the bill, the only disadvantage would be the depth of the redesign of the enclosure would need a bit more than 10cm total. Should get loud enough to have the headroom you want being a RS180-4P and a RST28F-4. The baffle shape change may effect the xover a bit though and its a 4ohm load.
I think using a larger dia full ranger will give you undesired results as they are really meant for 2ch audio/nearfield and will have a much smaller sweet spot on the higher frequency's due to the cone size and getting 95Db loudness without distortion is big ask.(thats a lot of work for a single cone)
I was going to say that he is obsessing over them far too much.
They are on-axis plots in an anechoic chamber.
You almost always listen to them off-axis.
What amplifier?
Might give you some idea, but… it is a useful tool, but…
To quote Floyd Toole:
Unfortunately it is often a process of getting something, working and living with them, and then iterating and evolving. A diy speaker builder rarely stops at one.
dave
That's absolutely true! The brain analyses so much more as just an on axis measurement can tell.
But - we know pretty good what the brain is doing. And we have a LOT more measurements which give us information about how the speaker behaves in a room and what it's limits are. These Klippel Nearfield scanners give us a pretty good picture of what is going on and the results acutally CAN predict the sound of a speaker in a room: https://www.audiosciencereview.com/forum/index.php?threads/neumann-kh120-ii.43137/
It's not an omni mic and frequency response - but 100 measurements and some good analysis can do the trick.
I agree, I tend to overthink things 🙂. Maybe it is just time for me to build something and give it a listen to at least have a starting point.
Definitely agree with that. There will be no listener on axis with any speaker. I guess I am looking for two things in the data:
- off-axis behavior of those drivers. There is very little data on that, so I am trying to understand what to expect
- I am trying to correlate other peoples comments to data. This is mostly to help guide me in driver selection. I will then build/listen a prototype, and from there I hope I can correlate things I like/dislike in a speaker to a characteristic in data. I hope this makes sense.
I will likely use a Denon AVR receiver (most likely the X3800h).
Yes, I am sure this is how this will happen. Though I would love to understand how to make educated decisions so that I can improve from one iteration to the next.
Yeah, your earlier comments got me second guessing myself, so I took a closer look. Alpair 5s in rear (crossed over at 110hz), and that early pair of CHS-70 Gen1/UK spec that I think soon evolved into the original Pluvia7 in front height (also crossed over at 110hz into the LFE channel). Still playing around with REW and miniDSP (2x4HD) for hopefully finer tuning of the dual subs.
When setting measurement levels for those REW sweeps, one is reminded just how loud even 80dB SPL C weighted is at listening position*, much less THX. My last time in a theatre was for Oppenheimer, and yeah, it got painfully loud.
For fun, I played a few videos of the evolution of “Deep Note” - and it definitely those little subs a workout. Then there’s The Expanse’s Rocinante flying overhead - good times.
If I had to replace this all, I’m not sure exactly what direction I’d wanna take.
*edit: in the 15’x22’x8’ room, the baffles of main row is approx 24” front wall (picture window behind the TV requires stand mounted bracket for 77” screen), and main listening seats are at 12’ from mains, 14’ from front heights and 7’6” from rears. Seldom do non dedicated real world rooms allow for ideal acoustic configurations - I guess that’s what headphones are for? 😵
Last edited:
Babinsky - I infer from your statement of “most likely a Denon3800H” that you’ve not yet made a choice on the new(?) main piece for your system. Out of curiosity, what is your present kit, and your anticipated use case; i.e. EQ, room correction, total number of channels for immersion, etc?
edit:
Revisiting your original post, that’s not a huge room, and I’d be inclined to start with fewer channels. My current basement room configuration has a staircase and corner located passage doorway that precludes ear level surrounds, and over the past few (6 or so) years I found the biggest improvement in immersion from the recent addition of cheap ceiling mounted coaxial drivers in Atmos top mid position for a 5.1.4 array - all other channels aside from the subs are by Mark Audio, and I’m pretty happy.
For now….😵
edit:
Revisiting your original post, that’s not a huge room, and I’d be inclined to start with fewer channels. My current basement room configuration has a staircase and corner located passage doorway that precludes ear level surrounds, and over the past few (6 or so) years I found the biggest improvement in immersion from the recent addition of cheap ceiling mounted coaxial drivers in Atmos top mid position for a 5.1.4 array - all other channels aside from the subs are by Mark Audio, and I’m pretty happy.
For now….😵
Last edited: