I have a pair of original CHR-70s that I need to rebuild the enclosures for. I'd most likely stay with a smaller bookshelf design, probably ported (maybe sealed), but am open to alternatives. Mark Audio's site doesn't list any plans at the moment (for any driver, actually). Planet10 lists 2 bookshelves (milliSize and Golden Ratio) and the Pensil70.
Are there any other good designs worth looking into before I start, or are there specific advantages I should consider when choosing?
Are there any other good designs worth looking into before I start, or are there specific advantages I should consider when choosing?
Hey Tommy,
it depends on how you want to use your speakers?!
In general: The CHR-70 seems to be good in various enclosures. Needless to say that ventilated enclosures of whatever kind (except some small horns) will provide more low frequency information.
If you want to use them in "near-field-hearing" application, a small closed enclosure will work fine. I'am using them like that on my computer desk. Cabinets are ~5liter / 1.32gallons.
Another example is shown here: http://www.hifi-forum.de/index.php?action=browseT&back=1&sort=lpost&forum_id=267&thread=20
It's a 4liter / ~1gallone closed cabinet. Specs for the notch filter and the capacitor, which need to be placed in the "+" lead of the speaker to increase bass-perfomance, are listed in the first post.
Regards, Alex
it depends on how you want to use your speakers?!
In general: The CHR-70 seems to be good in various enclosures. Needless to say that ventilated enclosures of whatever kind (except some small horns) will provide more low frequency information.
If you want to use them in "near-field-hearing" application, a small closed enclosure will work fine. I'am using them like that on my computer desk. Cabinets are ~5liter / 1.32gallons.
Another example is shown here: http://www.hifi-forum.de/index.php?action=browseT&back=1&sort=lpost&forum_id=267&thread=20
It's a 4liter / ~1gallone closed cabinet. Specs for the notch filter and the capacitor, which need to be placed in the "+" lead of the speaker to increase bass-perfomance, are listed in the first post.
Regards, Alex
If you're thinking that a small bookshelf sized enclosure would be right for you, the 5 liter "milli" sized mMarS (sealed) works like a charm. It's probably no surprise that I've heard most of the P10 designs, and I generally prefer the imaging of the narrow baffle designs over the Golden Ratio.
http://homepage.mac.com/tlinespeakers/FAL/downloads/mMarS-1v0-map-231009.pdf
a couple of suggestions;
due to Marks' built-in BS compensation, and if they are actually placed in a bookshelf near a rear wall, baffle step compensation may not be necessary
use decent quality plywood, not MDF (or contact Dave at commercial site re flat pack kits for these in 15mm BB)
- at one time the thought was to indicate the primacy of the 13 liter enclosure first designed for the CSS FR125, then FE127E, but once other drivers entered the picture with their different volume requirements, the naming convention got very confusing - I still try to think in terms of 3 basic form factors - but you know Dave
agreed, but sometimes when it's a matter of hang from the wall on brackets, in a bookcase or nothing, I'll take the not nothing.
CHR-Ken for short (dCHR-Ken70 in full form, d=deci (as in one sze down from the original Fonken) and 70 for the 70mm CHR (i am anticipating other sizes of CHR eventually)). Name coined by a member here, and pronounced as per the sea monster.
dave
CHR-Ken for short (dCHR-Ken70 in full form, d=deci (as in one sze down from the original Fonken) and 70 for the 70mm CHR (i am anticipating other sizes of CHR eventually)). Name coined by a member here, and pronounced as per the sea monster.
dave
Dave can you describe the dCHR-kens enclosure? I see that loans are for sale on your site, but I don't have terrible confidence in my woodworking skills. This is a fonken, so it has slotted, forward facing vents? And what is pricing like? Thanks!
The larger green/ w silver drivers on the upper right are our demos. These are still doing us service so aren't up for sale. There are versions of this cabinet for A7/A7.3/EL70/FF125wk that use the same shell. At some point trapezodal versions will also be availble (working thru the betas at the moment). The CGR versions (Classic Golden Ratio) are posted for free and are easier to build.
We will do a bespoke order, contact me about pricing, these are not on the price list.
dave
CGR-dCHR-Ken variants
These are my recently completed mark audio CGR-dCHR-Ken variants.
This is only my second DIY. Both have been based on Dave's planet-10 designs (Thanks for the plans Dave).
main differences:
I had to use different thickness of ply, So the design had to be modified to suit my available materials. Also there no divider (as yet) in the vent. The main regret it that i don't have access to a router which meant i could not have the driver flush with the baffle.
There is however a CNC router going in at the workshop where i work in the future which makes me happy for the the next project
I spent more time finishing this time than the last time and i think it has paid off as the look great (the colour is 'Space' by montana). I used a bobbin sander at 45degrees to chamfer the back of the baffle and holey brace holes.
My impressions of the sound so far (1 day burn in) is that they are pretty picky with amps.
when i plugged them in for the first time i was shocked by the lack of mid and lower mid frequencies. the top end needed to be rolled off but the bass extension was pretty nice. I found this when i had the CGR-dCHR-Kens were plugged into a sure electronic TA2024 D-class amp. I had great success with the sure amp when i built my FR125S-4L5-aperiodic boxes. I think the FR125s benefitted from the detailed high end that the sure amp provided, off setting the limit of the drivers top end.
So, not being happy with the sound of my new speaker i decided to attach them to another amp. I hooked them up to a couple of Flying mole dadm100pro mono blocks.
The improvement was dramatic. Though still slightly lean in the lower mids and still a bit forward in the top end, i could live with that. The extra power from the Moles sorted them out. I think a softer sounding amp could help them further
Cheers
Luke.
These are my recently completed mark audio CGR-dCHR-Ken variants.
This is only my second DIY. Both have been based on Dave's planet-10 designs (Thanks for the plans Dave).
main differences:
I had to use different thickness of ply, So the design had to be modified to suit my available materials. Also there no divider (as yet) in the vent. The main regret it that i don't have access to a router which meant i could not have the driver flush with the baffle.
There is however a CNC router going in at the workshop where i work in the future which makes me happy for the the next project
I spent more time finishing this time than the last time and i think it has paid off as the look great (the colour is 'Space' by montana). I used a bobbin sander at 45degrees to chamfer the back of the baffle and holey brace holes.
My impressions of the sound so far (1 day burn in) is that they are pretty picky with amps.
when i plugged them in for the first time i was shocked by the lack of mid and lower mid frequencies. the top end needed to be rolled off but the bass extension was pretty nice. I found this when i had the CGR-dCHR-Kens were plugged into a sure electronic TA2024 D-class amp. I had great success with the sure amp when i built my FR125S-4L5-aperiodic boxes. I think the FR125s benefitted from the detailed high end that the sure amp provided, off setting the limit of the drivers top end.
So, not being happy with the sound of my new speaker i decided to attach them to another amp. I hooked them up to a couple of Flying mole dadm100pro mono blocks.
The improvement was dramatic. Though still slightly lean in the lower mids and still a bit forward in the top end, i could live with that. The extra power from the Moles sorted them out. I think a softer sounding amp could help them further
Cheers
Luke.
Attachments
Hi Dave
OK, i'll get that in. I'll paint it white and give the space cyclops a front tooth.
Thanks.
nice ...
disjunction: Very nice little enclosures.
Regarding the sound: you can't have it all. These enclosures are verging on being almost impossibly small (anything approaching milk jug size, 4 litres). Even some of the best commercial examples of expensive small speakers can have what may appear to be a sizzling top end, a slight forwardness to the mids and recessed bass, depending on the balance the designer has struck. I recall the original ProAC Tablettes. I heard them in a very expensive system in a very expensive home in Calgary in about 1989 or 1990. Everything had been put together by someone who knew what they were doing. They had what sounded to be similar traits as you mentioned. But when a pair of Velodyne subs (the original ULD-12) the system became something altogether ...one of the hallmarks in my then young audiophile life...
Your comments about differing results with different amps is really the crux of system matching, something that a lot of folks simply do not take into consideration. I don't like the idea of tailoring a system to a particular component and then offsetting the rest of the system based on that component. The pieces should be good on their own and have the attributes you value most. Then see how they play together after that. If not, every time you change a component it will require more than one component to be changed (ah, the slippery slope...).
Even using similar topologies, various implementations can have profound effects. Thankfully the Sure is really cheap and can be modified, which should be fairly straight forward.
The speakers do look very good. You could add a "supra baffle" to the front if you want to have the smooth look (drivers flush mounted), which can have an effect on the sound as well.
disjunction: Very nice little enclosures.
Regarding the sound: you can't have it all. These enclosures are verging on being almost impossibly small (anything approaching milk jug size, 4 litres). Even some of the best commercial examples of expensive small speakers can have what may appear to be a sizzling top end, a slight forwardness to the mids and recessed bass, depending on the balance the designer has struck. I recall the original ProAC Tablettes. I heard them in a very expensive system in a very expensive home in Calgary in about 1989 or 1990. Everything had been put together by someone who knew what they were doing. They had what sounded to be similar traits as you mentioned. But when a pair of Velodyne subs (the original ULD-12) the system became something altogether ...one of the hallmarks in my then young audiophile life...
Your comments about differing results with different amps is really the crux of system matching, something that a lot of folks simply do not take into consideration. I don't like the idea of tailoring a system to a particular component and then offsetting the rest of the system based on that component. The pieces should be good on their own and have the attributes you value most. Then see how they play together after that. If not, every time you change a component it will require more than one component to be changed (ah, the slippery slope...).
Even using similar topologies, various implementations can have profound effects. Thankfully the Sure is really cheap and can be modified, which should be fairly straight forward.
The speakers do look very good. You could add a "supra baffle" to the front if you want to have the smooth look (drivers flush mounted), which can have an effect on the sound as well.
Hi Nanook
I'm with you on all your comments. The bass though is not really a problem. It's every thing from approximately ~350Hz-1KHz which is pushed back. thats what surprised me.
The range in a bout ~5Khz upwards is pretty forward and sizzly.
I'm sure breaking these in a will loosen things up a bit in the lower mids as the rubber gaskets free up. I think the fact that the sounded better with extra power of the flying moles may hint at that.
I did have them paired with a Rel sub last night and they sounded nice but still that won't help the lower mids as i really only use the rel for ~70Hz down.
The lower mids are better on my tiny (but three year old) CSS FR125s aperiodic boxes.
I have a set of varicaps that i will put onto the sure amp at at some point.
I'm not really complaining. I'm happy that i managed to successfully follow and modify a plan and coe out with a good result....does two sets of DIY speakers under my belt mean i now have a hobby? I do have a set of HiVi b3s' at home that i'm thinking of turning into a pair of desktop speakers. i guess the answer is yes.
Cheers
I'm with you on all your comments. The bass though is not really a problem. It's every thing from approximately ~350Hz-1KHz which is pushed back. thats what surprised me.
The range in a bout ~5Khz upwards is pretty forward and sizzly.
I'm sure breaking these in a will loosen things up a bit in the lower mids as the rubber gaskets free up. I think the fact that the sounded better with extra power of the flying moles may hint at that.
I did have them paired with a Rel sub last night and they sounded nice but still that won't help the lower mids as i really only use the rel for ~70Hz down.
The lower mids are better on my tiny (but three year old) CSS FR125s aperiodic boxes.
I have a set of varicaps that i will put onto the sure amp at at some point.
I'm not really complaining. I'm happy that i managed to successfully follow and modify a plan and coe out with a good result....does two sets of DIY speakers under my belt mean i now have a hobby? I do have a set of HiVi b3s' at home that i'm thinking of turning into a pair of desktop speakers. i guess the answer is yes.
Cheers
Triple Chr-70.3 Line array.
Hey All,
I saw the modular line array for the Chr-70.3 over at Madisound and thought it might be fun to experiment with a floorstanding line array transmission line ala Bill Fitzmaurice's Tlah.
Here is what I came up with.
The enclosures are still very rough. Just still experimenting really. I dont know that much about designing TLs but I recently built some Tlahs for a client so I used that for a base. 52" long (quarter wave of Driver Fs) and 6.25 wide tapering from 5.5" to 3.25" I need to get out the measuring rig, but these seem to go strong down to 60 and then roll off below that, although not super steeply. Full range they play just fine with all my music except some of the bassier stuff. I listen to mostly contemporary folk/bluegrass and some rock. Nothing too heavy.
First impressions are good. As I have seen suggested by Dave at Planet 10-hifi, the combing is not overpowering. It seems like pretty even response around the room. At higher levels they are a little shouty. Over all, though the sound is really nice. Good enough that I am going to keep on with the experiment.
So far with these drivers, there is just a little something missing on the top end to me. They are very smooth and warm. Really easy to listen to, but when I listen to a good dome tweeter, there is just a little definition that I wish was there. I had the same impression with the Twin Castle Chr-kens here:
I am going to experiment with stuffing and wiring with the arrays. Also, this is for a home theater primarily, so little eq from the receiver might be all it needs. I might try an ERT26 on top of the Array and see if I like it.
I will keep updating my experience here.
Benj
Hey All,
I saw the modular line array for the Chr-70.3 over at Madisound and thought it might be fun to experiment with a floorstanding line array transmission line ala Bill Fitzmaurice's Tlah.
Here is what I came up with.
The enclosures are still very rough. Just still experimenting really. I dont know that much about designing TLs but I recently built some Tlahs for a client so I used that for a base. 52" long (quarter wave of Driver Fs) and 6.25 wide tapering from 5.5" to 3.25" I need to get out the measuring rig, but these seem to go strong down to 60 and then roll off below that, although not super steeply. Full range they play just fine with all my music except some of the bassier stuff. I listen to mostly contemporary folk/bluegrass and some rock. Nothing too heavy.
First impressions are good. As I have seen suggested by Dave at Planet 10-hifi, the combing is not overpowering. It seems like pretty even response around the room. At higher levels they are a little shouty. Over all, though the sound is really nice. Good enough that I am going to keep on with the experiment.
So far with these drivers, there is just a little something missing on the top end to me. They are very smooth and warm. Really easy to listen to, but when I listen to a good dome tweeter, there is just a little definition that I wish was there. I had the same impression with the Twin Castle Chr-kens here:
I am going to experiment with stuffing and wiring with the arrays. Also, this is for a home theater primarily, so little eq from the receiver might be all it needs. I might try an ERT26 on top of the Array and see if I like it.
I will keep updating my experience here.
Benj
To maintain a fundemental resonance of 1/4 wl of Fs when you taper the line as you have, you have to shorten the line.
So in essence you have tuned below Fs which usually has the effect of decreasing the bottom.
i'd guess that your line also has too small a cross-section for optimum performance.
dave
Interesting. My first thought would be that reducing the depth of the tube would necessitate that the tube be longer to maintain the same tuning.
Maybe someone here can enlighten me. What is the formula for the relationship of the cross sectional area and the driver Sd? Is there a good resource for functional TL theory? A book on functional design principles perhaps?
I saw in my email that Scottmoose replied here and might design a DW three driver TL, but I dont see it here. Did it get removed? @Scottmoose - If you do that please let me know!
Thanks,
Benj
Maybe someone here can enlighten me. What is the formula for the relationship of the cross sectional area and the driver Sd? Is there a good resource for functional TL theory? A book on functional design principles perhaps?
I saw in my email that Scottmoose replied here and might design a DW three driver TL, but I dont see it here. Did it get removed? @Scottmoose - If you do that please let me know!
Thanks,
Benj
The only relationship between driver SD and a resonant pipe's cross sectional area [CSA] is that there is none. MJK merely chose to use it as a convenient relationship in his MathCad software, which has caused considerable confusion same as Baily's TL paper did till recently WRT making CSA = Sd.
About the only advantage to using such a narrowly defined alignment is that ignoring some of today's ridiculously low Vas drivers, the vast majority will be very well [mostly very over] damped once stuffed.
Consider that a TQWT/TQP [inverse tapered TL] can be viewed as a reflex morphed into one continuously contracting enclosure [alignment], ergo net Vb of the cab/vent dominates with driver effective Qts dominating net Vb and line length a function of both the closed end and the reflex vent's [TQWT terminus]' CSA; so me and others have successfully designed them for decades using a simple HP hand held calculator's T/S program or self designed computer program, with something similar before T/S except doing the math longhand.
I know of no books that spell out resonant pipe design theory other than those for musical instruments, so one must read various college level textbooks, AES, etc. papers if these are too confusing, then use the sound wave equation to design them.
All you need to know though are the basics of T/S theory, which is all over the net and the rest can probably be found here: HyperPhysics Concepts
GM
About the only advantage to using such a narrowly defined alignment is that ignoring some of today's ridiculously low Vas drivers, the vast majority will be very well [mostly very over] damped once stuffed.
Consider that a TQWT/TQP [inverse tapered TL] can be viewed as a reflex morphed into one continuously contracting enclosure [alignment], ergo net Vb of the cab/vent dominates with driver effective Qts dominating net Vb and line length a function of both the closed end and the reflex vent's [TQWT terminus]' CSA; so me and others have successfully designed them for decades using a simple HP hand held calculator's T/S program or self designed computer program, with something similar before T/S except doing the math longhand.
I know of no books that spell out resonant pipe design theory other than those for musical instruments, so one must read various college level textbooks, AES, etc. papers if these are too confusing, then use the sound wave equation to design them.
All you need to know though are the basics of T/S theory, which is all over the net and the rest can probably be found here: HyperPhysics Concepts
GM
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