I'm looking into adding two subs, maybe sealed or H-frame OB, and maybe run the H OB further into bass, and wanted to gain insight from the experienced.
My system: two 12" Rythmik servo subs in DIY sealed boxes below 65Hz in mono, and per side: one 18" Faital 18HP1010 baffleless dipole on a swing from 65 to 275Hz, twin 8" from 275Hz to 1.8kHz (bottom 8" on U baffle to reach to 275Hz) and AMT above. Active 4-way, digital xo and room correction.
Happy with Rythmik sealed subs and thought about adding two more to get a distributed bass array. And I came across GR Research/Rythmik OB servo subs in H or W baffle, getting great comments, that can be xo up to 200 or 250Hz. Looking at their model with dual 12" per sub.
And this has me thinking about these options:
The room: it's the living room, with little flexibility as to placement. It's 30x16x2.4 feet high, divided into two sections (dining and living room) by a wide sliding door. Current subs and speakers shown in blue, and the listening seat.
The grey squares show where the two new sealed subs would go, or where the sealed subs would go should I get OB subs. OB subs could be placed somewhat away from the corners, but baffle would likely be about 30" from front wall.
What are your thoughts about OB vs sealed bass below 65Hz?
And baffleless 18" vs twin servo 12" on a baffle in 65 to 200Hz region?
Thanks in advance!
My system: two 12" Rythmik servo subs in DIY sealed boxes below 65Hz in mono, and per side: one 18" Faital 18HP1010 baffleless dipole on a swing from 65 to 275Hz, twin 8" from 275Hz to 1.8kHz (bottom 8" on U baffle to reach to 275Hz) and AMT above. Active 4-way, digital xo and room correction.
Happy with Rythmik sealed subs and thought about adding two more to get a distributed bass array. And I came across GR Research/Rythmik OB servo subs in H or W baffle, getting great comments, that can be xo up to 200 or 250Hz. Looking at their model with dual 12" per sub.
And this has me thinking about these options:
- add two sealed Rythmiks to the existing two and play 20-65Hz.
- add two GR Research H baffles to the two sealed and play all of them 20-65Hz. I wonder if mixing sealed with dipole bass, despite both being servo-driven, would be detrimental.
- add two GR Research H baffles and play them 20-200Hz with the two sealed reinforcing 20-65Hz. Getting DBA below 65Hz. 2x12" have less surface than a 18", probably noticeable from 65 to 100Hz or so, but the GR have servo so allegedly more controlled/articulated than the 18".
- add two sealed Rythmiks to the existing two and play 20-65Hz, and later add two GR Research doing 65-200Hz with a shallower H or just a panel. This might in turn drive me to replace the 18" with a 12" dipole which eventually would allow to raise the xo to the mids from 275Hz to 400Hz or so.
The room: it's the living room, with little flexibility as to placement. It's 30x16x2.4 feet high, divided into two sections (dining and living room) by a wide sliding door. Current subs and speakers shown in blue, and the listening seat.
The grey squares show where the two new sealed subs would go, or where the sealed subs would go should I get OB subs. OB subs could be placed somewhat away from the corners, but baffle would likely be about 30" from front wall.
What are your thoughts about OB vs sealed bass below 65Hz?
And baffleless 18" vs twin servo 12" on a baffle in 65 to 200Hz region?
Thanks in advance!
With a max length of 30 feet you should be able to get at least to 30Hz, if not lower, with dipole bass. You might want to orient the dipole sub so that the front-back axis is aligned with the longest room dimension.
You might consider adding a mono sub adjacent to and facing your listening chair, to the left or right of it. You would practically be in the nearfield and could enjoy the clean bass of the Rythmik system with less worry about room interactions. One sub should be enough, when placed close by.
You might consider adding a mono sub adjacent to and facing your listening chair, to the left or right of it. You would practically be in the nearfield and could enjoy the clean bass of the Rythmik system with less worry about room interactions. One sub should be enough, when placed close by.
Thanks, but steep digital xo (Neville-Thiele 2nd order) has worked better for me and won't go for shallow.
I had not thought about that. If I place the OB subs where the blue boxes are and align them along the long axis they would be 90 degrees from the listening position, so not a good place. Maybe on the side, but will likely face resistance for aesthetic reasons. Will think it through.
Do you think it's ok to mix 2 sealed and 2 OB subs, or are you thinking OB subs instead of sealed?
Yeap, this I have considered but don't have a way to do this for aesthetic/practical reasons. Have furniture where the sub should go.
You already have dipole "bass" down to 65 Hz. That's already pretty low. Honestly, you will likely be better served by adding more of the servo subs you already have. The dipole sub is not going to do any "magic" compared to your current setup, and its placement seems to be problematic. The CB subs are much more forgiving in terms of placement, can be against walls, etc.
I have a pair of the triple open baffle subs using the GR Research drivers and Rythmik amps. It's the best bass I've ever had in my system (45 years as an Audiophile with some pretty high end speakers). Danny Ritchie often uses two sealed servo subs along with the OB subs when he demonstrates at audio shows.
I also recommend rotating your system 90 degrees so you are better taking advantage of the longer axis. Even so, the power of two ratio is not ideal, but OB subs tend to interact with room modes less than sealed subs.
I also recommend rotating your system 90 degrees so you are better taking advantage of the longer axis. Even so, the power of two ratio is not ideal, but OB subs tend to interact with room modes less than sealed subs.
..well,
IF just going dipole - it definitely does something (audible) you don't get with monopole: it seems to audibly "banish" the lower freq. small room acoustic sensation of room pressurization.
This isn't necessarily preferable though, because tactile sensation takes a "hit" when compared to some monopole subs throughout the room.
For instance I have a very large floor-bounded mono dipole sub for my home theater setup.
The result is that at low freq.s it sounds far more like a movie theater than with one or more monopole subs.. but again, the result just isn't as "bombastic" when you get those low freq. effects. To remedy that I use 2 actuators per seat in my HT.
I find that you can get closer to the tactility of monopole subs if the dipole subs are positioned near field i.e. within a metre of the listening position or closer. There is no room pressurization but your body will feel the pressure of the air movement more viscerally due to the close proximity.
Yes, I've heard this before and asked Danny. Apparently at shows he does this to even out bass response at back seats.
His reply to me: "I would only consider the additional [sealed] woofers if you run them in the rear corners of the room and run out of phase from the front speakers. When we do this we typically set the crossover point on the rear of the room subs to 25 or 30Hz". Not sure what he meant by running out of phase, though.
Rotating the system 90 degrees is no small feat. I have treated 2 walls and ceiling with bass traps (my room dimensions are awful) and have a diffusor on the current back wall. So if I turn it around I would have a diffusor on only one side wall...and diffusors on side walls with dipoles aren't useful, plus the other wall would not have the diffusor and...yes, aesthetics rear their ugly head again
Plus the front wall would become a wall-to-wall glass sliding door where no diffusor can be placed.
Will think this through and try to get creative over the weekend.
You know what my answer is...it's here:
Sealed vs OB bass below 70Hz?
You can think it over all you want, but the first thing I would do is get some baseline measurements as there are warts in everyone's system, particularly in the low frequencies. You need to address them.
I used to have Danny's dual OB/Rythmik setup (2 of them) which I replaced with the setup I have now a few years ago. In retrospect I would consider the triple 12 OB Rythmik setup a bare minimum if the quest is for "audiophile" bass in 2ch systems. But you can go further. Much further.
The description with pictures and with measurements of my current setup is here (post#59):
Show me your Panels! | Page 3 | AV NIRVANA
There are several links to various sites to read if you have time this weekend.
Good luck on your quest.
Best,
Anand.
Sealed vs OB bass below 70Hz?
You can think it over all you want, but the first thing I would do is get some baseline measurements as there are warts in everyone's system, particularly in the low frequencies. You need to address them.
I used to have Danny's dual OB/Rythmik setup (2 of them) which I replaced with the setup I have now a few years ago. In retrospect I would consider the triple 12 OB Rythmik setup a bare minimum if the quest is for "audiophile" bass in 2ch systems. But you can go further. Much further.
The description with pictures and with measurements of my current setup is here (post#59):
Show me your Panels! | Page 3 | AV NIRVANA
There are several links to various sites to read if you have time this weekend.
Good luck on your quest.
Best,
Anand.
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Not sure I do. But I have noticed people replying to threads despite not having anything to add, maybe they have too much time to burn.
Thanks Anand! Will read over the weekend and process.
Discussion/Impressions:
The commentary offered here: Discussion/Impressions: is 100% spot-on in agreement with I have trying to tell the folks, for a few years now. At one time I was almost as diplomatic as you. But alas, my patience has grown thin here of late. Good job, Anand ! (ref to post #59)
The commentary offered here: Discussion/Impressions: is 100% spot-on in agreement with I have trying to tell the folks, for a few years now. At one time I was almost as diplomatic as you. But alas, my patience has grown thin here of late. Good job, Anand ! (ref to post #59)
Thank you Charlie. I appreciate the insight, which is especially meaningful to me as I realize how much you like dipoles. This, coupled with the reading following Anand's post, is steering me in the direction of adding sealed subs.
Thanks again for the input!
From the thread at Audiocircle I was under the impression you ran sealed servo subs. I see from post #59 that's not the case: sealed subs with 15" pro drivers (and one 21"). Have you heard Rythmik's servo sealed? Sealed subs with pro drivers are so much easier to source/build, but I believe servos are advantageous at these frequencies. Was wondering about your view. Don't get me wrong: I have plenty of respect for pro-drivers, in fact my 18" midbass, 8" mids, AMT tweeters are all pro-drivers.
Going through some links in your post #59 I realized I will need a miniDSP 2x4 to implement delays and PEQ with MSO beyond what is feasible with the PEQ in Rythmik's plate amps, despite my multichannel DAC and DSP capabilities from Acourate. And I understood what you meant as baseline. I have measured many, many times, played with integrating the two Rythmiks with their PEQ/phase adjustments and REW, but can't get good enough results with two subs, especially when their location is restricted by living room layout. 3 subs should be enough to achieve the results, but given location constraints I'm thinking 4 might be necessary.
Another thing I realized from reading the miniDSP note on tuning multiple subs is that they showed smoother bass extending higher up in frequency, which might be helpful in xo to the dipole midbasses higher than what I do today.
Cheers!
LewinskiH01,
I did try GR/Rythmik 12 inch sealed subs once upon a time. They are very good, clean midbass, etc...until you turn up the volume. Then SPL compression sets in. Don't forget that factor. I am sure the 15 inch and 18 inch Rythmik drivers are better due to their size, but they are not available to the DIY population to my knowledge (their commercial stuff looks gorgeous!).
The Italian manufacturers have been doing this stuff for years. Look at the Klippel measurements of German manufacturer, BMS, particularly the 18n462 if you can find it on the net. The BL(X), and Kms (X) are pretty much state of the art. As is the B&C 18TBW100. Look at measurements done by Josh Ricci at Databass. He has measured Rythmik as well, particularly the bigger woofers. They did very well, but for obvious reasons, Rythmik 'markets' them to the HT crowd.
Servo control is a very good implementation, particularly with smaller drivers (i.e. less than 15 inches) when you want the driver to have non varying inductance values while the driver is moving, which ensures excellent midbass. But these same 12 inch drivers, have heavy cones to ensure a low FS so you can have good low frequency extension. So in other words, they are killing 2 birds with one stone. But they are of low sensitivity. 86dB or less. Goodbye peak SPL levels. 110dB at the most. Remember that is at 1m. The sub is not next to you, so you lose SPL with distance.
The Pro Italian (B&C, Faital Pro, LaVoce, etc....) don't need that. Their Klippels already show they have excellent to exceptional BL(X) measurements and their suspension (Kms) doesn't fall apart, particularly at HIGHER SPL levels. And they are all BIG drivers. 15's, 18's, 21's, etc...you can use a little DSP and get that low end F3 that you need. And they are all MORE efficient. Much more. Minimum 90dB here, and most are 93, 96, etc...
These Pro drivers, which are not cheap by the way ($350-$1K), are able to take brutally large amplifier power, DSP, etc...and give you exceptional midbass (>50Hz) and pretty good bass (<50Hz). You want deeper bass extension? Build a bigger sealed box (which will help to an extent), or go bass reflex/passive radiator or use a driver with a lower Fs or use a super sub driver like Funk's 21 inch drivers that have tremendous midbass and bass all at the same time, but costs about $1K per driver. You pay for those aluminum shorting rings, underhung driver design, HUGE neodymium motors, etc...
Once you go with a bigger driver, it's hard to go back. Especially when midbass attack and detail are involved. I am sorry but 18 inch drivers are not 'slow' sounding at all, especially if we are talking about ones that have excellent motor design which is revealed by the Klippel measurements.
The next comment is addressing the modal region of the room. The modal region, at least in my room (and I am sure this is similar in several other 'small rooms'), is above 50Hz and below 250Hz which is my Schroeder transition frequency. In this region, there are several modes, all overlapping each other and causing havoc with your FR. You need to tackle this problem, but there are a few ways to do this.
1. Ensure that your mains don't play TOO low. My mains are sealed, and have an F3 at 60Hz. I don't high pass them. If your mains are ported, seal them and experiment.
2. Use multiple sub modules and don't be afraid of moving them around the room. With monopole subs, the advantage is you can keep them close to the walls and move them around. With OB's you are stuck with being 'X' feet away from the wall. And most OB builders want their OB subs right next or near their mains for looks or WAF or whatever. The location of low frequency modules really shouldn't be in the same area as your 2ch speakers. The 2ch speakers should be setup for imaging and minimizing SBIR.
3. Use some room treatments and/or DSP if needed. Room treatments are better, as the area of modal region overlaps with SBIR. SBIR is caused by where your main speakers are positioned as it is due to phase/antiphase interactions between the side wall, ceiling, and front wall as it relates to the listening position. I spent a few hours varying the distance of my mains to the front wall and side walls along with judiciously adding a few treatments.
When done right, a multibass setup has a minimum of 5 LF modules. 2 of them are your main speakers, which are somewhat restricted to midbass. The other 3 are your sub modules, whether OB, monopole or a mix. An extra sub (for a total of 4 subs) is nice to have as icing on the cake, although not necessary. My 4th sub, changed my FR by about +/-3dB at the most but not too much of an 'audible' improvement except at higher SPL's, which makes sense (due to less compression). Spatial variance in the low frequency FR (<250Hz) is minimized amongst multiple seated listeners if that is relevant in your setup. But even without multiple listening positions, bass is just more uniform for lack of a better word.
I don't think I help with my rambling but hopefully, this makes some sense.
Don't get me wrong this isn't the only way to do it. I have great respect for folks that want to only use OB sub modules, especially with certain genres of music like classical, etc...and in my buddy's setup where he has OB's and 2 sealed monopole subs, he really has a great measuring and sounding setup. But it took work. Not every GR/Rythmik customer I have seen is willing to do that kind of work nor do they understand how to do it as they are not trained to do so. I do think, before you implement any sub, whether 1 or multiple, you need to get good measuring with the software of your choice. I use REW which is free and easy to learn.
Best,
Anand.
I did try GR/Rythmik 12 inch sealed subs once upon a time. They are very good, clean midbass, etc...until you turn up the volume. Then SPL compression sets in. Don't forget that factor. I am sure the 15 inch and 18 inch Rythmik drivers are better due to their size, but they are not available to the DIY population to my knowledge (their commercial stuff looks gorgeous!).
The Italian manufacturers have been doing this stuff for years. Look at the Klippel measurements of German manufacturer, BMS, particularly the 18n462 if you can find it on the net. The BL(X), and Kms (X) are pretty much state of the art. As is the B&C 18TBW100. Look at measurements done by Josh Ricci at Databass. He has measured Rythmik as well, particularly the bigger woofers. They did very well, but for obvious reasons, Rythmik 'markets' them to the HT crowd.
Servo control is a very good implementation, particularly with smaller drivers (i.e. less than 15 inches) when you want the driver to have non varying inductance values while the driver is moving, which ensures excellent midbass. But these same 12 inch drivers, have heavy cones to ensure a low FS so you can have good low frequency extension. So in other words, they are killing 2 birds with one stone. But they are of low sensitivity. 86dB or less. Goodbye peak SPL levels. 110dB at the most. Remember that is at 1m. The sub is not next to you, so you lose SPL with distance.
The Pro Italian (B&C, Faital Pro, LaVoce, etc....) don't need that. Their Klippels already show they have excellent to exceptional BL(X) measurements and their suspension (Kms) doesn't fall apart, particularly at HIGHER SPL levels. And they are all BIG drivers. 15's, 18's, 21's, etc...you can use a little DSP and get that low end F3 that you need. And they are all MORE efficient. Much more. Minimum 90dB here, and most are 93, 96, etc...
These Pro drivers, which are not cheap by the way ($350-$1K), are able to take brutally large amplifier power, DSP, etc...and give you exceptional midbass (>50Hz) and pretty good bass (<50Hz). You want deeper bass extension? Build a bigger sealed box (which will help to an extent), or go bass reflex/passive radiator or use a driver with a lower Fs or use a super sub driver like Funk's 21 inch drivers that have tremendous midbass and bass all at the same time, but costs about $1K per driver. You pay for those aluminum shorting rings, underhung driver design, HUGE neodymium motors, etc...
Once you go with a bigger driver, it's hard to go back. Especially when midbass attack and detail are involved. I am sorry but 18 inch drivers are not 'slow' sounding at all, especially if we are talking about ones that have excellent motor design which is revealed by the Klippel measurements.
The next comment is addressing the modal region of the room. The modal region, at least in my room (and I am sure this is similar in several other 'small rooms'), is above 50Hz and below 250Hz which is my Schroeder transition frequency. In this region, there are several modes, all overlapping each other and causing havoc with your FR. You need to tackle this problem, but there are a few ways to do this.
1. Ensure that your mains don't play TOO low. My mains are sealed, and have an F3 at 60Hz. I don't high pass them. If your mains are ported, seal them and experiment.
2. Use multiple sub modules and don't be afraid of moving them around the room. With monopole subs, the advantage is you can keep them close to the walls and move them around. With OB's you are stuck with being 'X' feet away from the wall. And most OB builders want their OB subs right next or near their mains for looks or WAF or whatever. The location of low frequency modules really shouldn't be in the same area as your 2ch speakers. The 2ch speakers should be setup for imaging and minimizing SBIR.
3. Use some room treatments and/or DSP if needed. Room treatments are better, as the area of modal region overlaps with SBIR. SBIR is caused by where your main speakers are positioned as it is due to phase/antiphase interactions between the side wall, ceiling, and front wall as it relates to the listening position. I spent a few hours varying the distance of my mains to the front wall and side walls along with judiciously adding a few treatments.
When done right, a multibass setup has a minimum of 5 LF modules. 2 of them are your main speakers, which are somewhat restricted to midbass. The other 3 are your sub modules, whether OB, monopole or a mix. An extra sub (for a total of 4 subs) is nice to have as icing on the cake, although not necessary. My 4th sub, changed my FR by about +/-3dB at the most but not too much of an 'audible' improvement except at higher SPL's, which makes sense (due to less compression). Spatial variance in the low frequency FR (<250Hz) is minimized amongst multiple seated listeners if that is relevant in your setup. But even without multiple listening positions, bass is just more uniform for lack of a better word.
I don't think I help with my rambling but hopefully, this makes some sense.
Don't get me wrong this isn't the only way to do it. I have great respect for folks that want to only use OB sub modules, especially with certain genres of music like classical, etc...and in my buddy's setup where he has OB's and 2 sealed monopole subs, he really has a great measuring and sounding setup. But it took work. Not every GR/Rythmik customer I have seen is willing to do that kind of work nor do they understand how to do it as they are not trained to do so. I do think, before you implement any sub, whether 1 or multiple, you need to get good measuring with the software of your choice. I use REW which is free and easy to learn.
Best,
Anand.
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