I've fallen in love with the form factor of "desktop" guitar amps. What I want to kind of recreate is something like the Positive Grid Spark (I won't link in my first post ever for fear of being called a shill/bot lol). It is two 4" FR drivers, 40W total, in a ported box about 14"W x 7"D x8"H, and about 11-12lbs.
I'm looking for some recommendations specifically for the drivers. I'd like to keep driver price under about $80 for the pair.
The design I'm currently planning:
Thoughts?
I'm looking for some recommendations specifically for the drivers. I'd like to keep driver price under about $80 for the pair.
The design I'm currently planning:
- separate inputs for BT and guitar (wired). Using the guts of a multiFX pedal to do the amp/cab simulation DSP for the specific guitar Amp sound. (BT circuitry will be clean without Amp/cab DSP).
- Useage will be about 50/50 guitar Amp vs BT speaker.
- Planning about 30W per driver, but I'm flexible.
- Ideal build would be a sealed box but I want to keep very close to the small desktop form / dimensions listed above so may need a port. Hell I'm even open to infinite baffle open back like "real" guitar amps of my youth.
Thoughts?
These will sock your rox’s off: https://www.parts-express.com/Dayton-Audio-RS100-8-4-Reference-Full-Range-Driver-295-352?quantity=1
paper 8 ohm version: https://www.parts-express.com/pedocs/specs/295-359--dayton-audio-rs100p-8-specifications.pdf
paper 8 ohm version: https://www.parts-express.com/pedocs/specs/295-359--dayton-audio-rs100p-8-specifications.pdf
These Faital are OK, they have a little bite at 8k you might like for guitar.
https://www.parts-express.com/pedocs/specs/294-1123-faitalpro-4fe35-4-specifications.pdf
https://www.parts-express.com/pedocs/specs/294-1123-faitalpro-4fe35-4-specifications.pdf
I haven't built many speakers recently, but I figured Parts Express / Dayton Audio might be on the list haha.
I notice that DA speaker comes in 4 versions, 4 vs 8 ohm and AL vs paper cone. the AL 8 ohm has a sensitivity of 84 and the paper 4ohm has a sensitivity of 88. Typically guitar speakers are higher sensitivity in my understanding, would this be a reason to choose that variety?
Or should I focus more on other parameters first?
I notice that DA speaker comes in 4 versions, 4 vs 8 ohm and AL vs paper cone. the AL 8 ohm has a sensitivity of 84 and the paper 4ohm has a sensitivity of 88. Typically guitar speakers are higher sensitivity in my understanding, would this be a reason to choose that variety?
Or should I focus more on other parameters first?
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As everything in audio, that depends. You can have a speaker that is small, with bass, and/or loud. Pick two. I picked small, 4”, and with bass, so efficiency is low. If I picked an efficient 4” driver it wouldn’t have any bass - even for guitar and would resemble a 4” tweeter. So, there is a mandatory trade-off and physics rules. At 4” you may need to eq the bass a bit anyway.
I would look for the frequency response you want. Guitar speakers usually have peaks around 2-8khz that give the guitar color, sparkle, and presence, the problem is you don’t want that in an audio system. Guitars sound bland and boring when plugged into a stereo, your criteria are somewhat conflicting. If you get your guitar tone out of an electronic gizmo like a line6 or Spark pre-amp effects box then go for the hifi or pro sound speaker with a flat response. The Spark has all kinds of models in it so it should give you good sound if run through hifi speakers or pro-sound speakers with a flat response. The model of a Marshall stack will sound just like a very tiny Marshall stack🤣
I like the sound of paper over metal, probably because it’s what I’ve listened to my whole life. However, the bass from a metal cone can be impressive.
You picked one of the most common driver sizes, 4” speakers are used everywhere and you should be able to find a good one. Most of the 4” pro sound loudspeakers are designed for line arrays and to project sound over a large audience, so they sound pretty bright and edgy by themselves. There are 4” speakers for monitoring that have a good sound, they seem to be very rare. Speakers designed for hifi full range are often too delicate for the abuse a guitar player can put them through. So, I picked the Dayton for it’s flat response, decent power handling, and it’s relative low cost, in case you don’t like it or you blow it out.
88db is pretty good for a 4” driver, also you will have two in stereo for 91db. The Faital 4FE35 is rated at 91db, 94db in stereo. That’s pretty dang loud, I can hear my wife now 😡 You obviously can’t take this to the stage, but it should work fine for your desk. If you want more bass then you can add a subwoofer later.
I would look for the frequency response you want. Guitar speakers usually have peaks around 2-8khz that give the guitar color, sparkle, and presence, the problem is you don’t want that in an audio system. Guitars sound bland and boring when plugged into a stereo, your criteria are somewhat conflicting. If you get your guitar tone out of an electronic gizmo like a line6 or Spark pre-amp effects box then go for the hifi or pro sound speaker with a flat response. The Spark has all kinds of models in it so it should give you good sound if run through hifi speakers or pro-sound speakers with a flat response. The model of a Marshall stack will sound just like a very tiny Marshall stack🤣
I like the sound of paper over metal, probably because it’s what I’ve listened to my whole life. However, the bass from a metal cone can be impressive.
You picked one of the most common driver sizes, 4” speakers are used everywhere and you should be able to find a good one. Most of the 4” pro sound loudspeakers are designed for line arrays and to project sound over a large audience, so they sound pretty bright and edgy by themselves. There are 4” speakers for monitoring that have a good sound, they seem to be very rare. Speakers designed for hifi full range are often too delicate for the abuse a guitar player can put them through. So, I picked the Dayton for it’s flat response, decent power handling, and it’s relative low cost, in case you don’t like it or you blow it out.
88db is pretty good for a 4” driver, also you will have two in stereo for 91db. The Faital 4FE35 is rated at 91db, 94db in stereo. That’s pretty dang loud, I can hear my wife now 😡 You obviously can’t take this to the stage, but it should work fine for your desk. If you want more bass then you can add a subwoofer later.
Thanks for the feedback, it was helpful. I did not explicitly understand the tradeoff between efficiency and bass response, but it makes sense when thinking about it.
Everything you said was spot on to what I was thinking as well. (I also like paper cones)
I was anticipating the same thing you mentioned that the guitar would sound flat through a typical hifi speaker. That was the purpose for me adding an amp modeler / multiFX pedal upstream as a DSP preamp for the "guitar amp" half of the build.
The idea is that it is easy to remove the guitar DSP from the input, and then I can just use the amp and speakers "normally" (straight clean signal) as a BT speaker.
Reason for edit: I hit the post button too early, oops
Everything you said was spot on to what I was thinking as well. (I also like paper cones)
I was anticipating the same thing you mentioned that the guitar would sound flat through a typical hifi speaker. That was the purpose for me adding an amp modeler / multiFX pedal upstream as a DSP preamp for the "guitar amp" half of the build.
The idea is that it is easy to remove the guitar DSP from the input, and then I can just use the amp and speakers "normally" (straight clean signal) as a BT speaker.
Reason for edit: I hit the post button too early, oops
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I made a spreadsheet of the several different drivers and noticed that the RS100 are physically smaller than many other 4" drivers. I don't exactly know why, but that gives me pause.
If they perform the same, does it matter if they are 4" or 3.5"?
I guess not? Maybe that's a good thing, I would have a little more flexibility in the dimensions of the enclosure with smaller drivers if nothing else.
If they perform the same, does it matter if they are 4" or 3.5"?
I guess not? Maybe that's a good thing, I would have a little more flexibility in the dimensions of the enclosure with smaller drivers if nothing else.
I guess Parts Express rounds up? I don’t think it will matter much. A 4” in comparison to a 3.5” can have better bass and less treble, but as you are seeing in the data, it may not matter at all.
One thing to consider is that if you blow a 3.5” speaker it may be hard to find a replacement. Four inch speakers are everywhere.
One thing to consider is that if you blow a 3.5” speaker it may be hard to find a replacement. Four inch speakers are everywhere.
Can be fixed a little by increasing the cone dampening. I have used visaton lts 50 coating liquid.
6 thin layers was the point I found made no additional benefit for 4fe35.
And for a non destructive fix I have used felt pads for furniture on 4fe32 (neo). Simply apply symmetrical close to the transition towards the surround.
And @sac02
Take a deep dive in to reviews and talk about this series to get a feel for what can be done using Faital 4”.
https://www.img-stageline.com/products/flat-m100/?r=pdf
And I would be honored if you try and make my proposition for a single ported 4fe42 (awesome driver). In simulation it behaves better ported than its brothers and sisters 4fe35/32
https://www.diyaudio.com/community/threads/new-faital-pro-4fe42.397188/#post-7300420
When I see such small drivers and hear 'guitar', there are immediately popping some thoughts up. The first thing is "will it survive?" No, not the guitar playing but the pop when plugging/unplugging the guitar cable. Or a pedal. Or a defect cable/plug. It's not a question if it happens but when. The problem is, such a pop can instantly send the voice coil to smash on the back pole plate.
That happens quite easily on a ported enclosure because below the fb the cone has no resistance, only limited in excursion by the suspension. A sealed enclosure gives some protection, a stiff suspension can prevent that too but both will prevent most of the bass. A serial capacitor helps too but I think it would be more elegant to get the guitar its own input which got a HP filter on line level. Filtering the bass out will improve the max spl too and that won't impact the bass while using it as BT speaker.
@Arthur Jackson already said loud, small, deep, choose two. If you disregard bass for spl, this little guy got a sensational price and can go really loud (102dB!). Downside: 16 Ohm. A very cheap amp is good with higher impedance speakers and sounds great, the TDA8932 and you can get the boards for less than a big Coke at McDoof, it's ridiculous.
Another thought was, on a that small width, stereo will not give any real stereo image. So, why not go mono and use the panel space instead for a 2nd FR for a bass driver?
I don't know if that's something you can live with, I just wanted to give my 2ct to shine light on it from another perspective.
E: I forgot, this FR got most of the traits of a guitar speaker and got a good efficiency too and relatively stiff suspension. Dirt cheap too.
That happens quite easily on a ported enclosure because below the fb the cone has no resistance, only limited in excursion by the suspension. A sealed enclosure gives some protection, a stiff suspension can prevent that too but both will prevent most of the bass. A serial capacitor helps too but I think it would be more elegant to get the guitar its own input which got a HP filter on line level. Filtering the bass out will improve the max spl too and that won't impact the bass while using it as BT speaker.
@Arthur Jackson already said loud, small, deep, choose two. If you disregard bass for spl, this little guy got a sensational price and can go really loud (102dB!). Downside: 16 Ohm. A very cheap amp is good with higher impedance speakers and sounds great, the TDA8932 and you can get the boards for less than a big Coke at McDoof, it's ridiculous.
Another thought was, on a that small width, stereo will not give any real stereo image. So, why not go mono and use the panel space instead for a 2nd FR for a bass driver?
I don't know if that's something you can live with, I just wanted to give my 2ct to shine light on it from another perspective.
E: I forgot, this FR got most of the traits of a guitar speaker and got a good efficiency too and relatively stiff suspension. Dirt cheap too.
Hmm, I had not considered that. I did not realize that pop could be that destructive.
The electronics I planned on using on the guitar input don't have a discreet EQ. Do you have any thoughts for a way to implement a line level HPF, hopefully cheaply and easily?
I'm not totally opposed to this. The idea of using FR speakers was attractive at least partially because I could avoid some of the work involved in designing and building crossover networks though. And a large part of my inspiration for this was the look/form factor of the guitar amp which uses FR drivers of the same size. What drivers would you recommend?
You can use a RC filter, just capacitors and resistors. There are online calculators for the parts values.
You'll need equalizing for a FR too because of the baffle step, to find one which got the exact opposite frequency response to your baffle size is practically impossible. But you can use a EQ app on your phone/tablet that matches the profile. That's something you should use anyway since it will sound very differently outside vs standing on a desk indoors.
I can only recommend something if you can tell me what your expectations of the speakers are, frequency range, spl, dimensions of the speaker. For different size - just use a front cloth. That also gives some degree of protection for the drivers.
Neat idea but in a Leslie you don't rotate the speaker, you just rotate the horn.
I did not realize you could do this prior to amplification lol. I've always just assumed it's only done after the amp because I guess that's all I've ever seen! I just assumed you needed active EQ prior to the amp.
yeah sorry I didn't mention, I was planning to do baffle step correction
I don’t think there will be much baffel step on a desk top monitor, you are in the near field. Besides you have bass and treble controls, maybe? I’ve never seen a guitar amp with baffle-step circuitry. You just put it where it sounds good. If it’s good enough for Joe Pass, Les Paul, and Clapton, it should be good enough for you. Besides this is a boom box, it’s not hifi simply because of its basic structure.
You can stop the input thump with an RC circuit. Real easy. I don’t know why this hasn’t been standard on all guitar amps manufactured after say, … 1950.
You can stop the input thump with an RC circuit. Real easy. I don’t know why this hasn’t been standard on all guitar amps manufactured after say, … 1950.
The baffle step is a much shorter distance than the listening distance. Besides that, the near field doesn't omit any reflections (ie, the desk surface and, ofc, the baffle step).
Usually the bass/treble controls are way off the baffle step, which usually happens in the mid-range. It doesn't matter for who that fits, except for @sac02. I already suggested an EQ app, no matter if it's a phone, tablet, PC or laptop. He'll need several settings though because if he moves the amp/speaker, the FR will change. A lot.
I completely agree! from the parts cost, it's less than a $ in any case and nobody cares. WTH?! and that's 3/4 of a century ago!