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I am not at all an expert in this but I get F3 of 27 hz in a Portrd box. Dimensions of 40”x12”x15” and internal volume (excluding port, midrange enclosure and driver displacement ) of 60 litres. I am guessing that’s just based on passive design.
That great designer will be you Rick I am at this stage still considering various options - buy used gear, an off the shelf design by you or Jim or custom with you. I didn’t want the trolls on the form distract the conversation with comments around how as a newbie I have no idea and hence DIY is not for me (which it is not). That’s why I just said assume I am going to be working with someone master at this art without naming anyone.
Do you mean PMC MB1? PMC Twenty5.26 was ok but I did like MB1 a lot. It wasn’t just the bass. I liked the whole package in a way I haven’t for 6-7 other speakers I have auditioned - it had heft in bass at low volume, really sweet mid-range (but still had very clean seperation) and airy highs. Through all the auditions I have realised my head gets very irritated if the highs notes are even tiny bit hot. I have also seen I am attracted to speakers that have very clean sound where you can clearly separate each instrument. Other speakers I have auditioned include PMC Twenty5.26, Dynaudio Contour 60, Paradigm Persona 3F, KEF Refernece 5, Focal Sopra 2, B&W 802, Sonus Faber Amati.
RickCan’t seem to find the F3 of MB2. Anyway I also looked at specs for Dynaudio C4, another speaker I have liked (say 7.5/10) and that has F3 < 30hz too. So going back to original options, keen to get your view on 1. Going with something like Tempesta and getting a pair of High quality subs vs a speaker that goes to Under 30hz2. If full range speaker, I want height to be under 45 and width within 12”. Keen to get your view on hybrid vs fully passive and what could each design look like. Separately I am also hoping to try Rockport Atria in the next month or so. Here is what I have tried so far:1. Paradigm 3F : it did not feel very clean. Plus my hearing is really sensitive to high notes and I feel I can’t tolerate any level of brightness. 2. KEF Reference 5: there was nothing obvious missing but somehow it didn’t feel like I got the three elements I was looking for: heft in the bass at low volume, clean & sweet mids and airy top notes 3. PMC Twenty5.26 and Contour 60 - there wasn’t a clear winner. I preferred bass of Contour but midrange of PMC. Didn’t love High notes of any of these two4. Focal Sopra 2 and B&W 802 D3: Focal felt tight and precise. However lacked the soundstage of B&W. B&W had great wide soundstage. However didn’t quite have the separation of Focal. I also found focal to be a bit boomy, but that could just be the room.
It makes it difficult to make a good comparison when there's not much evidence of the measured performance. I'm kind of shocked that PMC only listed a frequency range with no +/- dB let alone response graphs. Being that they market heavily to the recording industry it's surprising. I can pretty much look at quoted specs and tell you if they are fairly accurate, especially if I know the drivers involved.-3dB @25hz (a true 25hz, not with room gain added in for advertising) is really tough to achieve in a fully passive speaker without a larger woofer and big cabinet. It's possible with an 8" driver but the sensitivity will be very low with a moderate cabinet size. If the woofer is designed for a smaller cabinet then the moving mass of the cone and other parts really makes it difficult to drive. The bass may go deep but the control / definition isn't very good.Moving up to a 9.5" (like the Satori W024) improves the sensitivity but it takes a fairly large cabinet to have a box tuning without peaking. This is bettered by the Scan-Speak 11" (more excursion and surface area) but again with a fairly large cabinet. The Scan-Speak has more limited upper end response than the Satori so the choice of midrange is more important; however, there is a good group of mids that will work fine with the woofer. If your target is 25hz the larger woofer with more excursion always wins in a passive speaker.So,yes, the passive 3-way can be done as long as you're tolerant of a bigger cabinet. The alternative is using an active bass section which allows more flexibility - sealed box, smaller cabinet, wider choice of drivers, etc. The DSP amps also give you the ability to do room correction/EQ which is a huge factor. No matter how good a passive design is I have witnessed many times over a listening room wreaking havoc on the bass with large peaks. If you don't have any EQ correction available in your front end equipment then a speaker with active DSP is your best solution. The Tempesta with outboard subs or integrated into a single cabinet is an excellent choice. The Epico could be done the same way as well. The floorstanding option would be within the dimensions you need.
Thanks Tyson. I am sure even above 30 Many other characteristics matter a lot more than F3 point.
PMC was about $19000. Used about $12k. I have yet auditioned Rockport Atria but I think that’s about $22k and used $12k. Can you guys point me to any hybrid/ active designs by one of the well known manufacturers (Wilson, Vandersteen, Magico, Rockport etc)? Just want to get some inspiration.