Hello,
I just ordered a pair of Markaudio CHP70 and I want to build them a simple and cheap BR to begin with them. I found a lot of plan for their metal sisters CHR70 or for pencils etc, but not a single one for CHP 70 BR.
Could you help me with figures (Vb, and port lenght for 4,6 cm diameter ?)
Qts = 0.572 ; Vas = 5.0 l ; Fs = 66Hz ; Xmax = 4.2 mm
Thanks in advance !
I just ordered a pair of Markaudio CHP70 and I want to build them a simple and cheap BR to begin with them. I found a lot of plan for their metal sisters CHR70 or for pencils etc, but not a single one for CHP 70 BR.
Could you help me with figures (Vb, and port lenght for 4,6 cm diameter ?)
Qts = 0.572 ; Vas = 5.0 l ; Fs = 66Hz ; Xmax = 4.2 mm
Thanks in advance !
Thanks dave,
In fact what do you think the FR will really look like - i have drawned a few imaginary lines (see picture) ? Won't this kind of driver and port tuning have a dip in the 100 Hz region ?
(this doesn't take into account baffle step and voltage source effects)
For the port, I need to look in some shops because the classic 50mm (46 mm inside) I have access to is only 10cm long = will be too short
I am also thinking of making a hole in glued wood blocks with the correct thickness inside the box (I have drill of 38 mm, but this should make a shorter length than a classic tube port, isn't it ?)
By the way, is it exactly 10 liters ?
Your software is exactly the one I was remembering seeing on some site (was yours in fact!) with excursions charts etc !
Best regards
Eric
In fact what do you think the FR will really look like - i have drawned a few imaginary lines (see picture) ? Won't this kind of driver and port tuning have a dip in the 100 Hz region ?
(this doesn't take into account baffle step and voltage source effects)
For the port, I need to look in some shops because the classic 50mm (46 mm inside) I have access to is only 10cm long = will be too short
I am also thinking of making a hole in glued wood blocks with the correct thickness inside the box (I have drill of 38 mm, but this should make a shorter length than a classic tube port, isn't it ?)
By the way, is it exactly 10 liters ?
Your software is exactly the one I was remembering seeing on some site (was yours in fact!) with excursions charts etc !
Best regards
Eric
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It is hard to say. With the MA i like to add a bit of a bump up to help fill in where the built in BSC hump starts to fall off. This whole region thou is dominated by the room.
You don't have a shop that sells plumbing pipe?
A slot port would be easier than gluing blocks and drilling.
dave
How do you bump it up there : BSC ?
It is just I am not sure plumbing pipe in a hole will look nice with a front firing box...
you'll note the 1 dB lump on the bottom of most of those sims... (BSC = baffle step compensation)
Personally i like the look better than the typical store bought port. Also cheaper & stiffer.
Our finished boxes are typicallyveneered and 99.9% of the time have a slot port.
If you are concerned with the look, rebate the back of the baffle around a hole the same size as the inner diameter of the pipe.
dave
I tried to imagine various effects on the driver : baffle step, voltage source (I use SET) etc
Some on a post proposed a notch filter around 2k rather than a BSC.
This could be rather flat, but still with a perhaps thin bass response, despite the + 1dB lump ?
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You my well find the affect of a notch on your amp worse that the original problem.
Obsessing over the freuancy reponse will get you no-where. On-axis FR only plays a modest role in a speaker system's ability to connect you to the emotion in the music
If you want a small, simple BR for the CHP, the 10 litre is close to as good as it gets (a guess based on my experience, since i've only played with its siblings). Build it, get 500 hrs on the drivers, and then you can worry about filters and such.
For more you could always just build Frugel-Horm Mk3, now known to perform very well with CHP. Or tempt me to do a Mar-Ken for these.
dave
Obsessing over the freuancy reponse will get you no-where. On-axis FR only plays a modest role in a speaker system's ability to connect you to the emotion in the music
If you want a small, simple BR for the CHP, the 10 litre is close to as good as it gets (a guess based on my experience, since i've only played with its siblings). Build it, get 500 hrs on the drivers, and then you can worry about filters and such.
For more you could always just build Frugel-Horm Mk3, now known to perform very well with CHP. Or tempt me to do a Mar-Ken for these.
dave
No, no !!- don't distract him, don't tempt him-- (at least till he comes up with a Mar-Ken for the 10.2's!
)Don
(at least till he comes up with a Mar-Ken for the 10.2's!
That exists... Chris has a pair on his workbench waiting for me to do drivers. I haven't done the trapezoid yet.
dave
OK, Dave.
If I compare each of these drivers characteristics,
the main difference I find is VAS = 6.1 for EL70 and 5.5 for CHP, the other ones are really close.
Considering the Mar-Kel 70, can I built it the same dimensions or add a little in order to tweak it?
Sure the damping will have to be adapted, and I will provide my experience when these box will be built, but I wouldn't start it the wrong direction.
If I compare each of these drivers characteristics,
the main difference I find is VAS = 6.1 for EL70 and 5.5 for CHP, the other ones are really close.Considering the Mar-Kel 70, can I built it the same dimensions or add a little in order to tweak it?
Sure the damping will have to be adapted, and I will provide my experience when these box will be built, but I wouldn't start it the wrong direction.
I will of course try with the raw driver first, I guess in the 10l BR.
But I learned the hard way that the Fostex 103e had a strong benefit with a BSC + Zobel in a BR enclosure. The treble curve + effect of voltage source with more than 30 ohm impedance at 20k was a very pronounced high treble near 100 dB/w/m with the rest of the driver around 90 db, and the bass less than that...
Other enclosures I tried were pleasant at first but quite fatiguing in the long term : lumpy TQWT, dead-end frugal horn etc…
Your ears gets easily accostumed to frequency responses...
What you loose in details and subtelty was given back by all frequencies playing music together ; and also better FR curve allowed me to listen longer to the music.
Yes, there is perhaps a little less emotion (but it is still there) but emotion isn't anymore at the detriment of my ears...
So I now don't want to have any prejudice against any options...
it also depends of the quality of your components (cement res. and most caps are bad sounding : for me the answer was Mills resistors and Mundorf bipolar lytics)
eric
A shop near me has tubes that are 40 mm inside, I guess here in France sizes should be globally metric.
A 38 mm diameter and 98 mm long should give 40mm and 110 mm, right ?
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