Hello everyone,
I have an old radio cabinet, that i want to turn into a speaker. Its inner dimensions measure roughly 33.5x24x58.5 cm. I have uploaded a picture of the box at the bottom of the post. Because its all in one unit, I assume a boombox type build would be best. Meaning 2 tweeters and 2 full range drivers. I would also like a woofer or mini subwoofer + a passive radiator aswell, shooting towards the front, since I'm a huge bass lover, however I'm not sure how the subwoofer would impact the rest of the build. I have been looking at a couple of drivers:
I have made a lot of conciderations, however im still unsure. I would appreciate any help i can get. I have tried to select some drivers that look good together, because i probably wont have a cloth or anything covering the drivers (I love the looks of drivers). Do you guys have any guidelines to speaker parts, which ones are better and worse or maybe some sugestions for drivers you would reccomend yourself. I also apologize if I have done anything wrong in this post, since its my first post here.
Thanks for everything, Dudedek
I have an old radio cabinet, that i want to turn into a speaker. Its inner dimensions measure roughly 33.5x24x58.5 cm. I have uploaded a picture of the box at the bottom of the post. Because its all in one unit, I assume a boombox type build would be best. Meaning 2 tweeters and 2 full range drivers. I would also like a woofer or mini subwoofer + a passive radiator aswell, shooting towards the front, since I'm a huge bass lover, however I'm not sure how the subwoofer would impact the rest of the build. I have been looking at a couple of drivers:
- Subwoofers/woofers:
- Full range:
- Tweeters:
- https://www.soundimports.eu/en/sure-electronics-aa-ab34181.html?
- categories=audio_components&price=2.45-116.95~%E2%82%AC
- https://www.soundimports.eu/en/arylic-up2stream-21-amp.html
https://www.soundimports.eu/en/tpa3116d21-bt.html
I have made a lot of conciderations, however im still unsure. I would appreciate any help i can get. I have tried to select some drivers that look good together, because i probably wont have a cloth or anything covering the drivers (I love the looks of drivers). Do you guys have any guidelines to speaker parts, which ones are better and worse or maybe some sugestions for drivers you would reccomend yourself. I also apologize if I have done anything wrong in this post, since its my first post here.
Thanks for everything, Dudedek
Seems like a fun project, and a good first post.
Some general thoughts:
1) I'd be inclined to go with a larger woofer/subwoofer since you mentioned loving bass. You can probably find an 8 inch that will fit in that enclosure volume and have good sensitivity and volume displacement. The passive radiator can go on the back without affecting anything.
2) A little larger midrange might be warranted depending on what amplifier you go with. A 4 inch midrange is typically quite a bit more capable than a 3 inch. Some of the 2.1 amplifiers have a cross point that may be low for a 3 inch driver depending on how loudly you want to play. I think some of those also have a high-pass on the left/right channels, which would simplify your crossover work. I haven't looked at them lately so can't suggest one, but someone that has will probably join the conversation.
3) Unless you're going for a retro vibe, the PRT-8 tweeter seems out of place. Technology has advanced significantly since then.
Some general thoughts:
1) I'd be inclined to go with a larger woofer/subwoofer since you mentioned loving bass. You can probably find an 8 inch that will fit in that enclosure volume and have good sensitivity and volume displacement. The passive radiator can go on the back without affecting anything.
2) A little larger midrange might be warranted depending on what amplifier you go with. A 4 inch midrange is typically quite a bit more capable than a 3 inch. Some of the 2.1 amplifiers have a cross point that may be low for a 3 inch driver depending on how loudly you want to play. I think some of those also have a high-pass on the left/right channels, which would simplify your crossover work. I haven't looked at them lately so can't suggest one, but someone that has will probably join the conversation.
3) Unless you're going for a retro vibe, the PRT-8 tweeter seems out of place. Technology has advanced significantly since then.
Thank you for your answer!
1) You mention a larger woofer/subwoofer so I've looked around and I found the B Acoustics SB23MFCL45-4 Subwoofer. I have heard great things about it and, although I couldn't find any information on the required sealed volume, I did find some people on this forum who have used it before in a 25.5L sealed box here. Doing some quick math, with a width of 25 cm for the sub compartment, I can get 20l max.
I've heard that a higher Xmax, means more air being pushed and therefore deeper/louder bass. This sub has an Xmax of 12mm. Any thoughts on this driver? And for the passive radiator, since its going on the back like you suggested, its appearance doesn't matter at all, so I assume I just have to find an 8" passive radiator.
2) I'm not quite sure what you mean here. Do you think its better to use a midrange woofer combined with a tweeter over a full range combined with a tweeter?
3) You are right here, I did choose it based on appearance aswell, but I also tried to pick some better tweeters. However the amount of tweeter types can be quite overwhelming. do you have any recommendation on tweeter types I should look into?
Also since the entire speaker is in one box, does stereo even matter?
And when it comes to volume, the radio currently has a volume of 47 liters. When you take in account for lost volume because of internal walls aswell as outer + additional volume for the amp and power and cable management in general, this volume probably goes down to 35L or less. The subwoofer takes 20L so there are 15L left for the two fullrange/midrange woofers.
I have tried to make a quick 3d model of what i think the speaker will look like
Thank you again for all the help, Dudedek
1) You mention a larger woofer/subwoofer so I've looked around and I found the B Acoustics SB23MFCL45-4 Subwoofer. I have heard great things about it and, although I couldn't find any information on the required sealed volume, I did find some people on this forum who have used it before in a 25.5L sealed box here. Doing some quick math, with a width of 25 cm for the sub compartment, I can get 20l max.
I've heard that a higher Xmax, means more air being pushed and therefore deeper/louder bass. This sub has an Xmax of 12mm. Any thoughts on this driver? And for the passive radiator, since its going on the back like you suggested, its appearance doesn't matter at all, so I assume I just have to find an 8" passive radiator.
2) I'm not quite sure what you mean here. Do you think its better to use a midrange woofer combined with a tweeter over a full range combined with a tweeter?
3) You are right here, I did choose it based on appearance aswell, but I also tried to pick some better tweeters. However the amount of tweeter types can be quite overwhelming. do you have any recommendation on tweeter types I should look into?
Also since the entire speaker is in one box, does stereo even matter?
And when it comes to volume, the radio currently has a volume of 47 liters. When you take in account for lost volume because of internal walls aswell as outer + additional volume for the amp and power and cable management in general, this volume probably goes down to 35L or less. The subwoofer takes 20L so there are 15L left for the two fullrange/midrange woofers.
I have tried to make a quick 3d model of what i think the speaker will look like
Thank you again for all the help, Dudedek
https://www.madisoundspeakerstore.c...cl45-4-8-polypropylene-cone-sub-woofer-4-ohm/
"Box recommendations: Sealed box of 0.4 to 0.5 cubic feet for an F3 of 65Hz. You would need to use a bass boost or DSP to push the driver into lower frequencies. The F6 is 45Hz and F10 is 35Hz.
Vented box of 0.8 to 1.0 cubic feet with a 2" port by 8" long for an F3 of 35 to 32Hz."
I don't have direct experience with that one, but it looks capable.
On passive radiators, standard practice is to have at least twice the volume displacement as the active driver. You can get that through using two similarly sized passive radiators (in both Sd and Xmax compared to active driver), one passive that's the same size with double the Xmax, or one passive that's larger diameter with same Xmax, etc.
Passive radiators can get pricey and involve a bit more modeling/measurement than just using a port. A port may be a better option if you don't have much design/measurement experience.
It really depends on the drivers and intended crossover. If you have a full-range that actually goes all the way into the upper end of the treble range, you will likely want a low-pass on it where the tweeter takes over. If you let them both cover the same range you will have constructive/destructive interference based on listener location (comb-filtering is the term often used for this). You are also likely to wind up with too much treble and a narrower listening window.
If you want to use a first order crossover, that would also make a full-range driver with low-pass more useful. Some midranges don't have a smooth enough or extended enough upper end to easily handle a first order crossover.
There are other midranges/midbasses that are designed to naturally roll-off smoothly in their upper range so a simpler crossover can be used with them. These might only require a high-pass on the tweeter for good integration. Midrange/midbass drivers with paper or polypropylene cones tend to be more suitable for this approach, but it's very driver specific.
Another thing you haven't mentioned is the potential to just use full-range drivers for the midbass-tweeter range. That could eliminate passive crossovers entirely if you choose the right amp. The simplicity there might appeal to you.
This mostly comes down to preference and crossover desires. Keeping your crossover point 2 octaves above Fs is typically a good general rule, though higher crossover slope and lower expected output can ease that a bit.
On dome type, some people prefer hard domes, while others like soft domes. Honestly, most newer tweeters from major manufacturers are pretty good. Some of the opinions on this topic tend to be holdovers from when hard domes first came on the market and some of them were pretty bad. Most of that is gone now, so anything with lots of use and good reviews will likely be fine for a typical listener. If you are going to run grille-less you might look at ones that have an integrated grille on the tweeter, since they are more physically fragile than the other drivers. If you don't have children, pets, or other speaker hazards in your environment this may not matter.
Not really at this size, though many amp modules tend to expect it, so sometimes summing features for the L/R channels are missing. Those things can be addressed, but it's one more thing to deal with. Obviously more drivers gives you more output capability, so there is benefit there as well if you want to be able to play loudly.
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Oh wow, thank you. That's around 22-28 liters as well, so that fits good i think.
You are right about that, plus i think it will be hard to fit two 8 inch passive radiators in the box, so a port seems like the easiest and cheapest option. Should it be front firing or back firing? As its most likely going to stand up a wall, ill assume a front firing one may be the best choice?
Oh, i didn't even think about that. So the full-range will produce from 500-20k Hz. I am slightly concerned about the higher frequencies though.
This is on the Dayton Audio RS100-4 4" Full-range. But from what i could find, basically all full range woofers have this drop. So if you listen to it from straight ahead, it shouldn't be a problem, but as soon as there is a slight angle, the sound starts distorting. But if this doesn't have the biggest effect on listening quality, i would prefer the simplicity (both looks and build process) of just the full-range drivers and sub.
If you want to be able to push the speaker all the way against the wall, then putting the port on another face is better. If you can leave a couple inches or so of clearance, a rear port would still be OK.
True, most full-range drivers will have a more pronounced fall-off in response when listening off axis when compared to 2-way with a dome tweeter. This is just a directivity issue mostly related to their size, but cone shape and how it decouples at higher frequencies can make some drivers produce a more consistent radiation pattern. The Markaudio model you mentioned earlier demonstrates that:
https://www.madisoundspeakerstore.c...arkaudio-chr-70-champaigne-cone-4-full-range/
The scale is different between the two plots, so keep that in mind, but overall the response is better behaved off-axis. Some EQ or tone control adjustment may be enough to make it acceptable across the typical listening window. On-axis may not be the primary listening location in an application like this.
If you build it with just the full-range drivers initially, it may be relatively easy to add tweeters if you feel the need later.
If I were doing a project like this, I would try to get a simplified prototype together with a minimum amount of work to judge how the basic pieces are working together and if you like it when you wander around the room.