Would using an Alpair 11ms in parallel with a CHR 120 (both 7.2 ohm) with the 120 having a 2.7 mh inductor in series, offer any advantage or disadvantage over twin CHR 120's?
Have cabinets with separate ported enclosures for each driver and wondering on best driver combination. Upper chamber is smaller than the lower and with narrower port.
Have cabinets with separate ported enclosures for each driver and wondering on best driver combination. Upper chamber is smaller than the lower and with narrower port.
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Apologies for the topic hijack, but I thought I'd update on this post; I finally received my CHR-120s! Super impressive. Love that they look like a monster version of my gold 7MSs.
This is a budget resto-mod job so my expectations aren't sky high but I'm certainly hoping the drivers can bring the cabinets back to life in a meaningful way.
I'm curious to try the original Pioneer SX-440 amplifier which was purchased at the same time as the cabinets - I've found a restoration kit on eBay which could be a fun parallel project.
Pandemic travel permitting I'll be travelling interstate to my father's place to fit the new baffles and drivers in the next month or two
The grille fabric is still in great condition and will be reused. Port is on the front as they'll be against a wall. Any recommendations for stuffing?
Update from interstate where I posted the CHR-120 drivers and new baffles up to my father for initial fitting tests!
I am visiting next week to help finish off which will include better sealing in the cabinets and then to start listening.
Thanks all for the input so far.
Also, I have just kicked off another build for a portable speaker using Pluvia 11s and the Compact Monitor 0v8 design... more to come
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I'm hoping the claimed reduction in directivity from MA on the P11s is helpful here - this speaker will be placed in situations where I will be moving around (office, garage, outdoor in the back of my car [12v], etc.).
Amp is a TPA3116 based 2ch board with bass and treble controls so I can dial the end-product in a bit more. Expectations aren't huge, this is more of an exercise in taking a "Misc" design and making it a little more misc!
I could have bought a portable speaker but hey... that would be boring.
Amp is a TPA3116 based 2ch board with bass and treble controls so I can dial the end-product in a bit more. Expectations aren't huge, this is more of an exercise in taking a "Misc" design and making it a little more misc!
I could have bought a portable speaker but hey... that would be boring.
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I have bought some (long) time ago a pair of CHP-70 from Scott. Finally I had some time to build the enclosures. I went for a small BR box design which Scott has published somewhere around here. I am not done yet but as it looks like that I might want to place the speakers in an Ikea bookcase with 33x33cm "boxes" shelves I was thinking whether I should move the BR tube from the back to the front. Somehow back firing bass reflex tube in such "box" does not strike me as a great solution. On the other hand front placement of the BR tube probably increases midrange output from the speakers.
I thought I better ask here what people think about that.
I thought I better ask here what people think about that.
It doesn't really, you don't get midrange leakage per se from vents. What you can get, if the vent is excessively long, are its own harmonic modes (vents are 1/2 wave resonators), or, if it's of an excessively small CSA, obvious noise from an excessively high air velocity through the duct. Since you're wanting to put them into a bookcase, shifting the duct to the front is a sensible choice if there isn't likely to be much space around & behind them. You might find a little bit of vent noise at high levels, but we pick our compromises according to our situation, & it shouldn't be excessive.
I finally finished my central speaker based mostly on the design shared by planet10. I'll publish pictures just after.
but strangely when i'm watching movies with deep bass, this central speaker Mark Audio Alpair 10.3 was having the coil hitting the bottom of the speaker and the speaker having very high excursion. is this the thing called bottoming-out?
Was can be the reasons of that? knowing that my amp is an ncore 252MP and the volume was not so high.
I even tried to set a crossover at 120Hz in order to avoid the speaker to go low but i think i will loose a part of what central speakers should provide, right?
It's not my design, & this thread was set up as a dumping ground for various boxes I work up that have no other home, so it's not really my place to comment. However, yes, taken as read, that is bottoming out, and you must be either cranking the volume very high, or have material with significant amounts of unfiltered LF content being fed through the central speaker to achieve that. A vented enclosure ultimately unloads 24db/octave below Fb so if you feed it with large amounts of energy below that, there is no acoustical load to the cone & it will flap about in the breeze. The coil should not be bouncing off the back-plate though as the suspension limits travel; the 10.3 also has a limiter to provide an audible warning of over-excursion.
Don't be frightened of HP filtering a centre channel. Centre channels were primarily created to improve dialogue imaging for off-axis viewers. There isn't a whole lot of LF in dialogue, so let the mains & bass units handle the LF, not the centre channel. That's what they're designed for. Centres are not.
Don't be frightened of HP filtering a centre channel. Centre channels were primarily created to improve dialogue imaging for off-axis viewers. There isn't a whole lot of LF in dialogue, so let the mains & bass units handle the LF, not the centre channel. That's what they're designed for. Centres are not.
Not really.
That centre will not reproduce low bass. As with any speaker box with a hole in it, below tuning it will go crazy if excited. 80 Hz would be better than 120 Hz thou.
dave
Jace, I’ve been running a slight cosmetic variation of that centre channel enclosure (front baffle angled up at 5dg) for several years now with no issues. Currently driving the front row 3 with ICEpower A200, with centre’s HP set to 120Hz, but even with lower setting, I’ve never heard any distress. Does the problem occur at all listening levels, or only at higher SPLs? My room is mid sized (~340sq ft) and moderately damped acoustically, and primary listening distance is approx 10ft, and levels seldom breach 90dB, except on peaks.
L&R mains are also A10.3, in Scott’s Pensil enclosure - a very capable design - with HP set to THX default of 80.
L&R mains are also A10.3, in Scott’s Pensil enclosure - a very capable design - with HP set to THX default of 80.
Probably an ignorant question, but I'm trying to make life complicated for myself, and wondering about the Alpair 11 water buffalo design in post #34. If I wanted a similarly sized enclosure, but a larger front baffle, how terrible would it be to increase the front, decrease the back, and keep the interior footage the same? I'm sure there are principles I'd be violating.
Hi Scott, I was wondering if you have any unpublished designs of the Alpair 12pw kicking around? I have seen about 4 designs from you, a TL, folded TL (not sure if this is Dave's or yours), and a couple of bass reflex ones. One of the bass reflex designs I have come across by emailing Mark Audio directly, however, I've never seen you publish it anywhere. I think the size for it is most ideal for me as I'll be using it as a bass extender/WAW kind of unit (it's 607mm tall). I was wondering if it's possible to move the 12pw higher up in the cabinet without having any negative side effects as I always see mention of crossovers and 1/4 wavelength spacing.
It would be nice to hear your thoughts on the importance of this when crossing over somewhere like 300-500hz. It'd be also nice to hear your opinion on the pros and cons of the MLTL compared to the bass reflex option for the 12pw.
It would be nice to hear your thoughts on the importance of this when crossing over somewhere like 300-500hz. It'd be also nice to hear your opinion on the pros and cons of the MLTL compared to the bass reflex option for the 12pw.