I've had a pair of Speedster kit speakers in my posession for a few years now. They're excellent nearfield monitors, covering most of the musical range by themselves in a small package. I'm quite happy with them, but as with all things the tinkering began about a year ago. Some pretty serious EQ was brought to bear on these, trimming the excess brightness and cleaning up my room modes/desk bounce, etc. The bass management in particular has become quite cumbersome, totaling 9db of boost and a 4th order cut at 40hz. The frequency response is incredible now. No fatigue, deep resolving bass, no midbass hump, etc. All this boost however has completely overloaded the port at high listening volumes. I'm getting unimaginable chuffing. In the long run, my answer will be to add a sub like the SB3000 Micro.
For now, I'm thinking about replacing the port. In theory, this could be resolved with a simple flare, right? I cut a new port with total length equal to the previous, same diameter, same tuning with less interference, yes?
The next, more extreme option would be adding passive radiators. I've modeled a number in VCAD and my best bet to match the W4-1720 is the Peerless 830880. They do not fit on the back. A full half inch too long, unfortunately. To fit them on the existing enclosure I would have to remove and plug the rear port and mount them on their sides. Not sure how that would affect the sound to be honest. It does remove around 3db from the bass response.
My last, most extreme option would be to recreate the slot port design of the enclosure. I've been considering an enclosure redesign but haven't gone through with it. The slot port has a wider opening, lower tuning, and a broader, lower air velocity peak. I'm not that excited about the front facing nature of the port, either.
I'll take literally any recommendations for how to solve this. Cheaper is better, but I plan to have these for a long time. I could invest in them a bit if convinced.
Some reference material, EQ and VCAD sims are attached.
For now, I'm thinking about replacing the port. In theory, this could be resolved with a simple flare, right? I cut a new port with total length equal to the previous, same diameter, same tuning with less interference, yes?
The next, more extreme option would be adding passive radiators. I've modeled a number in VCAD and my best bet to match the W4-1720 is the Peerless 830880. They do not fit on the back. A full half inch too long, unfortunately. To fit them on the existing enclosure I would have to remove and plug the rear port and mount them on their sides. Not sure how that would affect the sound to be honest. It does remove around 3db from the bass response.
My last, most extreme option would be to recreate the slot port design of the enclosure. I've been considering an enclosure redesign but haven't gone through with it. The slot port has a wider opening, lower tuning, and a broader, lower air velocity peak. I'm not that excited about the front facing nature of the port, either.
I'll take literally any recommendations for how to solve this. Cheaper is better, but I plan to have these for a long time. I could invest in them a bit if convinced.
Some reference material, EQ and VCAD sims are attached.
Attachments
A simple flare will help very little.
Regardless of the size of the port, it will be "blown out" and chuff when boosted below Fb- if you want lower frequency output, tune lower- your simulations show Fb's in the 50Hz range, not going to work with boosts below that frequency.
A fourth order HP should be used just below Fb, and any boosts only around Fb.
To reduce port velocity related wind noise requires a larger, longer port for the same Fb, which would require external ports since the box has already been built and it's volume is fixed.
A slot port could be added externally, and vent to the rear or side if you don't like the sight of it.
You could plug the port, which would make for a sealed box alignment . . . and then revise your EQ profile.
However, boosting to high levels at frequencies well below Fs will likely reduce the life of the midwoofers.
Probably a good idea to have an extra pair (or two) of the midwoofers on hand too.
However, boosting to high levels at frequencies well below Fs will likely reduce the life of the midwoofers.
Probably a good idea to have an extra pair (or two) of the midwoofers on hand too.
Or if you do it right aperiodic. But now you give up bass. Doesn’t seem the Speedsters don’t won’t look like they do the bass you’d like.
Subs or a more capable enclosure might be where you need to look
Link to the design?
On vents I do not like round pipes and avoid them.
At some point following ideas invoked by an Audax Onken for their awesome Pro 15” I started breaking a lot of vent “rules” with very positive results. But I had to exchange ultimate extension for finesse & elegance in the bass
dave
I would suggest a bundle of heavy plastic straws and extent them a few inches beyond the rear port. If you like the result
glue the straws together and paint them. It will look like you added a Gatling gun to the back. 🙂.
glue the straws together and paint them. It will look like you added a Gatling gun to the back. 🙂.
I ran across that in the mid70s following the work of a guy who evetually came up with a much better execution, doesn’t do a hole lot but might help bandaid the chuffing issues
Mission baked a cosmetic version of the straws into one of their vents. I like using open cel foam, adding discs of it until I get the damping right
dave
Mission baked a cosmetic version of the straws into one of their vents. I like using open cel foam, adding discs of it until I get the damping right
dave
Lost me on that on. Adding disk? Like mass on a passive radiator?
I was suggesting that the mini ports be extended beyond the outside by 2-3-4-5-6".
The answer for me is go get a bigger speaker. LOL
I have a couple pairs of first Infinitesimals. They have a 4" driver and a ribbon or planar I can't remember.
Pretty easy to ruin one of them with todays amps though. I think the OP is asking a question that will lead to
an early death of that driver in that box. A GEQ/PEQ will add the frequency you target, that has nothing to do with the driver/cabinet (s) ability to deliver what you ask for.
If you think about what you're trying to do, a bass box is a suggestion. It's not really a sub if it's above what you can FEEL.
It's a sub/bass combo. 20-125 or 250hz.
Sit on sub, that will work. You can mass load the cabinet, feel the bass and if you turn it loud enough loose a few pounds at the same time.🙂
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The foam I have comes in about a 3” wide by 1” thick strips. I cut disks of it and add them till overdamped then remove 1
dave
That will lower tuning as you are changing the vent length
You now have a whole nether problem
dave
So then what about PRs? I haven't actually used them ever, but I keep hearing about them. I'm losing some output by adding mass and suspension to the design, but they could theoretically help me play lower cleaner, right?
Fundamentally the first post by @planet10 has it down. I'm not getting the bass I want out of these speakers and I'm definitely asking too much of them. Adding the sub is a $500 solution. I'm really asking how I can get it to fail more gracefully. It'll do great until I put on a particular track or two and it'll just fart out sub bass at high output. The PRs are a $60-100 solution. Wouldn't this also help when handing off bass to a sub anyways by smoothing the rolloff or something?
Original design is in the OP but now it's here and the link to the site I bought it from.
https://sites.google.com/site/undefinition/bookshelf-speakers/speedster
https://meniscusaudio.com/product/speedster-speaker-kit/
Fundamentally the first post by @planet10 has it down. I'm not getting the bass I want out of these speakers and I'm definitely asking too much of them. Adding the sub is a $500 solution. I'm really asking how I can get it to fail more gracefully. It'll do great until I put on a particular track or two and it'll just fart out sub bass at high output. The PRs are a $60-100 solution. Wouldn't this also help when handing off bass to a sub anyways by smoothing the rolloff or something?
Original design is in the OP but now it's here and the link to the site I bought it from.
https://sites.google.com/site/undefinition/bookshelf-speakers/speedster
https://meniscusaudio.com/product/speedster-speaker-kit/
This is my favorite answer
The woofer looks like it would work nicely in an ML-TL.
Did they provide matched prs of woofers? I have found their T/S for enuff apart to not even be considered a pr.
Bigger box, deeper bass.
dave
Did they provide matched prs of woofers? I have found their T/S for enuff apart to not even be considered a pr.
Bigger box, deeper bass.
dave
Sheesh! In HR its 30 W vent mach peak is ~41 m/s and only ~9 W/~17 m/s and with sufficient damping it rolls off below ~120 Hz 🙁, but it's a bookshelf speaker so fine as is and add a sub for < 120 Hz for max power handling.
Personally don't like PRs above ~35 Hz; this driver needs an inverse tapered TQWT.
Personally don't like PRs above ~35 Hz; this driver needs an inverse tapered TQWT.
Interesting. I'm not into fixed port, if they have ports I've used the straw method and usually get enough difference
by extending the port slightly, between 1-4". It lowers the FR response just a bit and slows the roll off mechanically.
https://www.parts-express.com/BOSS-CUBE8-8-400W-Powered-Subwoofer-with-Enclosure-265-4065
Under 200.00 for an 8" powered sub and free shipping. A pair 400.00?
Regards
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curious to know the Fs number you measured with it. It has indeed a good sounding reputation, as the 15" wooden from Davis that unluckilly asks too much for it... Also found the Audax expensive related too excellent italian 15" as well.
perhaps after a speedster the op is needing a Carrera ? Not the same price though, and seing it is used as desktop system it is maybe overkill.
Which indicates that it was not tuned right in the first place
And Scott has done a box that turns your Speedsters into ML-TLs if you are interested in more bass naturally instead of overEQing
dave
I don't want anyone to think I don't like these speakers. They're quite nice and can play pretty damn loud without equalization. On a regular day with all the negative preamp I put on them, they probably don't hit 30 watts or 100db often. It just kills me that the woofer can play the notes down low and loud decently but the port can't handle it. Having them for two years, looking at the tiny imperfections of my first cabinet up close every day makes me want to see what else I could get out of them in a bigger hurry than I'd normally go about. The fact that I know what went into it scratches that monkey part of my brain that wants to take it apart and do it again but better.
Once upon a time I thought about converting these to towers and/or 2.5-ways before I decided I could stand seeing an 8" in my living room. Now these are firmly on my sit/stand desk. There are a lot of compromises in doing that, like the cliff I've carved into the 100-180hz region from all the desk resonance. I recently borrowed my friend's SVS SB3000 Micro and it made me realize what I've been missing so far as clean low output. My current desk amp is not ideal for that. No crossover. More $$ to solve.
I guess I'll start saving my quarters for a sub. Shame amplification is getting so expensive. Doesn't really seem worth it to build my own when SVS has a warranty and an outlet.
Once upon a time I thought about converting these to towers and/or 2.5-ways before I decided I could stand seeing an 8" in my living room. Now these are firmly on my sit/stand desk. There are a lot of compromises in doing that, like the cliff I've carved into the 100-180hz region from all the desk resonance. I recently borrowed my friend's SVS SB3000 Micro and it made me realize what I've been missing so far as clean low output. My current desk amp is not ideal for that. No crossover. More $$ to solve.
I guess I'll start saving my quarters for a sub. Shame amplification is getting so expensive. Doesn't really seem worth it to build my own when SVS has a warranty and an outlet.