Hey diyers,
I completed my first build recently – a pair of Pensil P70s (Markaudio CHP 70 gen 2 drivers in these boxes: https://www.markaudio.com/online_shop/ch/chp-70-generation-2/ ). I've ended up buying a pair of Pluvia 7HD drivers to replace the CHP 70s because, despite expectations, the 'vintage' sounding upper frequency response wasn't for me. The box dimensions of the Pensil P7HD and P70 are very similar, so I figured it might work out okay.
To cut a long story short, I'm not getting good bass extension with either of the drivers and I'd like to canvass opinions to troubleshoot. When I say 'not good', I mean I've got the bass dial on my (cheap vintage) amp turned way up, and I'm still not getting any real impact from a kick drum or bassline. Is there anything obvious that I could be getting wrong? Could it be to do with how I've put the stuffing in (fairly evenly, I think?), or with the build more generally?
There are a few things I did slightly differently to the norm during the build:
Any thoughts?! I'd love to solve this. Fwiw, the mid and high ranges sound fantastic! Just hope I can sort this bass issue out without buying a subwoofer (and a new amp which will serve one). If there's no easy fix, could it be worthwhile building a basic crossover and adding a couple of small subwoofer drivers to the boxes? Feels risky but keen to hear any thoughts.
Thanks,
Lewis
p.s. pictures of the speakers below
I completed my first build recently – a pair of Pensil P70s (Markaudio CHP 70 gen 2 drivers in these boxes: https://www.markaudio.com/online_shop/ch/chp-70-generation-2/ ). I've ended up buying a pair of Pluvia 7HD drivers to replace the CHP 70s because, despite expectations, the 'vintage' sounding upper frequency response wasn't for me. The box dimensions of the Pensil P7HD and P70 are very similar, so I figured it might work out okay.
To cut a long story short, I'm not getting good bass extension with either of the drivers and I'd like to canvass opinions to troubleshoot. When I say 'not good', I mean I've got the bass dial on my (cheap vintage) amp turned way up, and I'm still not getting any real impact from a kick drum or bassline. Is there anything obvious that I could be getting wrong? Could it be to do with how I've put the stuffing in (fairly evenly, I think?), or with the build more generally?
There are a few things I did slightly differently to the norm during the build:
- Used screws as well as glue for all connections (didn't have enough clamps)
- I haven't actually soldered the speaker cable to the driver inside the box yet – just twisted the wire around the connector bits
- I guessed which connector on the driver should be connected to which side of the speaker cable – is there a rule on this? The CHPs have colour signifiers, but the Pluvias don't
- Used cheap binding posts
- Mounted the front baffle onto the side panels, rather than between them, if you know what I mean. I of course adjusted panel dimensions accordingly
Any thoughts?! I'd love to solve this. Fwiw, the mid and high ranges sound fantastic! Just hope I can sort this bass issue out without buying a subwoofer (and a new amp which will serve one). If there's no easy fix, could it be worthwhile building a basic crossover and adding a couple of small subwoofer drivers to the boxes? Feels risky but keen to hear any thoughts.
Thanks,
Lewis
p.s. pictures of the speakers below
It's a 4in fullrange driver so you may be expecting too much as far as kickdrums etc. go. There's a limit to how much air a cone with only 50cm^2 surface area can move. However:
You may want to try reducing the stuffing density a bit. I designed the cabinets with removable back specifically to allow people to easily tailor this -with the pensils, this is how tuning is (within reason) adjusted. You may also wish to ensure none is in excessive proximity to the cone as it (or rather the air) can mass-load the moving components.
Not ideal as they can end up causing leak-paths unless you're very careful. Some heavy weights and a flat surface can be a good substitute for clamps -as I, being the world's worst woodworker, discovered when I had the same problem. If possible, go over the joints & check they're air-tight.
A good connection is always necessary, but assuming it's a decent contact as-is, soldering should just help keep them in place & maintain the connection consistently.
There should be small + & - markings near the terminals. If you've managed to get the two drivers out of phase (easily done) that may not be helping.
Makes no difference.
Ditto.
Don't add additional drivers within the same air volume; each requires its own space (unless you know exactly what you're doing). You can internally partition to keep them isolated however.
What you've built is a "polite" speaker in that regard. You'll need to add another "subwoofer" cabinet to your system to get the "impact" you want. Polite speakers dont knock you over when you walk in front of them. Fortunately, the speakers you have are providing the mids and highs in a good way. In the US, subs are a dime a dozen; I've got a good one sitting out in the garage I can only give away; I think it'd solve your issue nicely. Unfortunately, you're half a world away and it's big and heavy!
At least I'm better than somebody. Barely.
The FHs and Pensils do a good job of extending the bottom (neither is designed to maximize the extension potential) and there ar emany comments like this “i can’t believe the bass from those 4” drivers”. But limited swept volume means they are hard pressed to deliver the slam of a much larger woofer.
dave
dave
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Check phase - try flipping the + and - connection from your amp on one of the speakers (just one). Low frequency gets better, or worse? You can check with a AA battery also, if it's in holder and you can connect wires to the speaker posts (disconnect amp). Battery + and - to spkr + and - should make the cone move out. Just brush the wires against the terminals, don't leave it hooked up for any extended time. Battery test can require 3 or more hands and extra long arms =P.
Check that your box is air tight - play a low frequency tone, maybe 70 Hz or so, at reasonable volume. (eg
) Inspect all seams / penetrations closely for noise or the feeling of air. Ear right up against the seam, or damp lips to feel for a breeze. Leaky box will prevent the one intended hole (the port) from functioning correctly.
Scottmoose mentioned both of these things, but I figured I'd go into a bit of extra detail since you mentioned this is your first build. No offense meant, if my comments seem a bit elementary.
Also, your hookup picture is giving me anxiety. Your speaker wires seem about to short together. Please allow me to suggest snugging your banana connectors all the way up to the insulation on your speaker wire, and then trim off any extra copper hanging out the other end.
Check that your box is air tight - play a low frequency tone, maybe 70 Hz or so, at reasonable volume. (eg
Scottmoose mentioned both of these things, but I figured I'd go into a bit of extra detail since you mentioned this is your first build. No offense meant, if my comments seem a bit elementary.
Also, your hookup picture is giving me anxiety. Your speaker wires seem about to short together. Please allow me to suggest snugging your banana connectors all the way up to the insulation on your speaker wire, and then trim off any extra copper hanging out the other end.
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4 inch driver has a lower limit of about 50Hz, and since it is not sufficient to reproduce frequencies below that, it cannot reproduce low frequencies such as those of a 6inch or 8inch.
60Hz for 3 inch, 50Hz for 4 inch, 40Hz for 6 inch, 30Hz for 8 inch, add a subwoofer if we want lower.
60Hz for 3 inch, 50Hz for 4 inch, 40Hz for 6 inch, 30Hz for 8 inch, add a subwoofer if we want lower.
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Wow, thank you so much everyone for your replies! I just checked back in to see if anyone had any ideas to find many of the names I've been reading lots of over the past months. Particularly great to have the designer himself in on it 🙂
As much as I do need to remember I'm working with a very small driver, I don't think this was just a case of me expecting too much. At the time of my first post, I was really getting very little low end at all ("impact" might have been the wrong word for me to use). But thanks for your guidance on this @planet10 , @jjasniew and @Scottmoose .
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So, some progress! And I will play around with the stuffing now to see if I can make any further gains. But I'm still having an issue which I don't think stuffing modifications will solve. Playing the 70Hz test tone has been really helpful in identifying this issue but it was apparent with music beforehand. The low end sounds really full and audible in certain parts of the room at certain heights. If I stand up, it's pretty basically all over the room, but specially right above the speakers and at the far end of the room. But if I sit down, the bass is massively reduced, and most audible way out to the side of the speakers. In fact, the WORST position (where the test tone isn't coming through much at all) is the 'listening' position (I haven't measured it out or anything, but roughly making an equilateral triangle). Fwiw, my room is about 5mx4mx2.6m(h). I currently have the speakers in an accessible place, about 50cm out from the wall but right in front of my record shelves. Eventually, I was planning to just put them in the corners (3.5m apart) but I'm starting to worry these speakers might be quite sensitive to positioning issues, if that's even possible.
Oddly I haven't had this problem with other speakers, I don't think. Does anyone have any thoughts about what could be going on? I'd be thrilled if I could get the low end to sound like it does when I'm standing up, when I'm sitting in the listening position!
As much as I do need to remember I'm working with a very small driver, I don't think this was just a case of me expecting too much. At the time of my first post, I was really getting very little low end at all ("impact" might have been the wrong word for me to use). But thanks for your guidance on this @planet10 , @jjasniew and @Scottmoose .
I'll try check for any leaks. At some point I'll cover screw heads/fill the holes with wood filler before veneering. I might also go over all the joins with more wood glue to seal up any tiny holes.
Embarrassed to admit that I think this might have been the main problem! That said, I can't find and + or - markings for the life of me! (Anyone with a Pluvia 7HD able to show me??) But I experimented with swapping the connections round and have solved a phasing issue. They're sounding much better now.
Eek. Advice very much welcome! I had read/seen something about this but it clearly didn't stick with me. I'll correct now. And thanks for your extra detail re phasing and seals.
Appreciate the gesture, in any case 🙂
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So, some progress! And I will play around with the stuffing now to see if I can make any further gains. But I'm still having an issue which I don't think stuffing modifications will solve. Playing the 70Hz test tone has been really helpful in identifying this issue but it was apparent with music beforehand. The low end sounds really full and audible in certain parts of the room at certain heights. If I stand up, it's pretty basically all over the room, but specially right above the speakers and at the far end of the room. But if I sit down, the bass is massively reduced, and most audible way out to the side of the speakers. In fact, the WORST position (where the test tone isn't coming through much at all) is the 'listening' position (I haven't measured it out or anything, but roughly making an equilateral triangle). Fwiw, my room is about 5mx4mx2.6m(h). I currently have the speakers in an accessible place, about 50cm out from the wall but right in front of my record shelves. Eventually, I was planning to just put them in the corners (3.5m apart) but I'm starting to worry these speakers might be quite sensitive to positioning issues, if that's even possible.
Oddly I haven't had this problem with other speakers, I don't think. Does anyone have any thoughts about what could be going on? I'd be thrilled if I could get the low end to sound like it does when I'm standing up, when I'm sitting in the listening position!
This sounds very much like a room issue rather than a speaker issue. Getting a good room treatment and/or position can be as important as building the speakers.
Basically the room is being pressurised by the speakers, and at certain wavelengths (based on dimensions of the room and also dimensions of speakers from each other and the listening position) you can have cancellations and/or peaks in your bass response due to reflections interacting with each other. Try putting your speakers in some different positions and see how the bass changes. You might end up needing to treat the room with bass traps?
I’ll let others with much more knowledge than me corroborate the above.
Basically the room is being pressurised by the speakers, and at certain wavelengths (based on dimensions of the room and also dimensions of speakers from each other and the listening position) you can have cancellations and/or peaks in your bass response due to reflections interacting with each other. Try putting your speakers in some different positions and see how the bass changes. You might end up needing to treat the room with bass traps?
I’ll let others with much more knowledge than me corroborate the above.
Room dominates below about 300 Hz. 70 Hz is often the standing wave caused by a ceiling a bit over 8 feet (2.4m)
dave
Thanks again guys. I figured it was a room thing but great to have comfirmation and some more detail. Having repositioned the speakers (and removed some stuffing) the bass response has improved. Still a bit of a standing/sitting issue but I can live with it! Room treatment not really an option in my flat, but I’m happy