I currently have a pair of 300B monoblock SET amplifiers that I like a lot. My speakers are a custom set of North Creek Rhythm in bookshelf size and I'm not satisfied with the bass. It's punchy and sounds ok, but it always feels a bit disconnected from the music and the level of bass is quite a bit lower than the rest of the music. Certain music passages can also sound a bit like the midrange is coming from a plastic cabinet speaker. Each speaker cabinet has a pair of Vifa P13WH-00 midbass drivers and a Scan Speak D2905 (All are made in Denmark, so older vintage.) The cabinets have an approximate volume of 15 liters and are ported with a pair of 2.5cm X 11cm bass reflex ports on the back. I believe an/the issue is that the cabinets are far too small for the driver configuration. They seem to perform best when away from a wall, so I don't believe they are designed to be corner speakers. My issues are compounded by an odd shaped room, where corner placement is not an option. The largely square portion of the room is approximately 10' X 10'. I've experimented a bit with speaker placement and it hasn't made a huge difference. I have a doorway on one side and a cabinet on the other side of the room, so there aren't two corners to put the speakers in.
I'm largely pleased with the mid and very pleased with the treble performance. I'd like to get rid of the occasional "plastic" sound and have more bass and low frequency extension that sounds natural and connected to the music. I mostly listen to jazz, classical and random pop and rock. This system won't really play heavy metal or electronic music where there is a lot of subsonic bass. I also only have 8 watts to work with, so efficiency is important. Would it make sense to design a more suitable cabinet for the existing drivers or move in a different direction? I'm also not trying to spend a million dollars on things, so new audiophile speakers are out and I'd rather not take on the hassle of restoring vintage speakers. I have some DIY ability and tools, but I don't really have the skill or tools to do sophisticated things like a transmission line cabinet. If I go in a different direction, some advice on drivers is appreciated. I read a bit about the Jantzen JA8008-HMQ driver and it seems to be the direction I would want to go if I use different drivers, given my space and power constraints. I've looked at the specs on a number of Faital Pro drivers, but I'm concerned about my little amps being able to work well with a high power speaker (despite the claimed high efficiency.) One consideration was to buy a set of speakers that meet the size and appearance requirements and replace the drivers and crossovers with high quality components. I prefer listening to the music to sawing and gluing, so I'd prefer to do something that doesn't require a lot of DIY if I can help it. If I can keep the budget to under $1000, it would be ideal. Any advice for me?
I'm largely pleased with the mid and very pleased with the treble performance. I'd like to get rid of the occasional "plastic" sound and have more bass and low frequency extension that sounds natural and connected to the music. I mostly listen to jazz, classical and random pop and rock. This system won't really play heavy metal or electronic music where there is a lot of subsonic bass. I also only have 8 watts to work with, so efficiency is important. Would it make sense to design a more suitable cabinet for the existing drivers or move in a different direction? I'm also not trying to spend a million dollars on things, so new audiophile speakers are out and I'd rather not take on the hassle of restoring vintage speakers. I have some DIY ability and tools, but I don't really have the skill or tools to do sophisticated things like a transmission line cabinet. If I go in a different direction, some advice on drivers is appreciated. I read a bit about the Jantzen JA8008-HMQ driver and it seems to be the direction I would want to go if I use different drivers, given my space and power constraints. I've looked at the specs on a number of Faital Pro drivers, but I'm concerned about my little amps being able to work well with a high power speaker (despite the claimed high efficiency.) One consideration was to buy a set of speakers that meet the size and appearance requirements and replace the drivers and crossovers with high quality components. I prefer listening to the music to sawing and gluing, so I'd prefer to do something that doesn't require a lot of DIY if I can help it. If I can keep the budget to under $1000, it would be ideal. Any advice for me?
It’s best to think of your loudspeaker & power amplifier as a two-part system. Could you tell us more about the amplifier, such as who manufactured the output transformers and what taps are on the secondary?
Fair enough. Thanks for the reply! I got the equipment second hand, so my knowledge of everything about the system is a bit limited. Here goes with what I know. Everything is DIY. The speaker cabinets were designed with help from North Creek, and are essentially bookshelf versions of their Rhythm floorstanding speaker with the drivers I described in my first post. The amplifiers seem to be based on the Electra-Print "300B Direct Reactance Drive SET Amplifier w/Ultimate Upgrade." Possible more information. The schematic that I have came from Welborne Labs website, which is no longer around. The builder told me that the output transformers were hand wound and came from "the guy" (his words, but would have been in the 2004-2006 timeframe) in Las Vegas, so they may also be Electra-Print, but I'm not sure. All of the components are high rent, so I'm pretty sure he didn't skimp on the transformers. They are single tap, 8 ohm output. The output tubes are Shuguang 300B-Z and there are no markings on the 6N1P tubes, so I'm not sure what they are.
That’s funny, I had Electra-Print in mind when I asked the question. Those are good, wide-bandwidth transformers. If you are chasing higher efficiency loudspeakers, you would be wise to consider a waveguide style horn with a compression driver for the high frequencies coupled to a sensitive woofer for the lows.
An issue with tube amplifiers is that due to the DCR of the windings of the output transformers, the output impedance is higher than one would see with a typical solid state amplifier, which is assumed to be near-zero ohms. At it stands, the majority of loudspeaker crossovers are designed with the assumption they are being driven with a solid-state amplifier. An advantage of DIY is that one can work around this and design the passive crossover of a loudspeaker to accommodate a specific, known output impedance. Additionally, one can also design a crossover that flattens the impedance curve of a loudspeaker driver. The result is a more constant impedance being reflected back on the output transformer’s primary, which is the load your output tube is working into.
A varying impedance in a loudspeaker isn’t typically a problem for a solid state amplifier but for a tube amplifier, that impedance manifests itself as a varying load on the output tube, which in turn causes measurable frequency response aberrations in the amplifier itself. Some of these aberrations contribute to that “tube sound” coloration which some people may find pleasant on some types of recordings. If your philosophy allows for non-neutral sound reproduction, this may be something you might enjoy.
I mention this because your current tweeters have an impedance as shown by the blue line in the graph below:
It’s actually fairly flat and probably isn’t wreaking havoc on your SETs frequency response. A typical compression driver, on the other hand, has an impedance that looks something like the graph on the right:
These impedance variations can be tempered somewhat in the crossover design, whether or not to do it (and to what degree) is something still debated on forums. Most people are running solid state amplification so it stands to reason that most loudspeaker designers wouldn’t waste their time flattening the impedance of a high frequency driver.
I bring all this up to drive home the point that tube amps and loudspeakers interact with each other as a system in much the same way a pair of loudspeakers interact with the room they’re placed in.
If I haven’t scared you away from compression drivers, good, that was not my intention. I have a push-pull tube amp I have used with a loudspeaker kit I built and it sounded fine, impedance peaks and all.
If you would rather build a kit than cut and measure yourself, I would recommend the Fusion 12 (98dB) or Fusion 15 (99dB) kits from diysoundgroup. They aren’t fullrange so you would probably be happier with an active subwoofer. If you can live with a little less sensitivity, there’s also the Maximus 12 design (95dB) from the same website. It would put you 30% over your stated budget and you would also have to build an enclosure for the drivers that sit atop the midbass module.
I hope you don’t mind all the food for thought. Good luck.
An issue with tube amplifiers is that due to the DCR of the windings of the output transformers, the output impedance is higher than one would see with a typical solid state amplifier, which is assumed to be near-zero ohms. At it stands, the majority of loudspeaker crossovers are designed with the assumption they are being driven with a solid-state amplifier. An advantage of DIY is that one can work around this and design the passive crossover of a loudspeaker to accommodate a specific, known output impedance. Additionally, one can also design a crossover that flattens the impedance curve of a loudspeaker driver. The result is a more constant impedance being reflected back on the output transformer’s primary, which is the load your output tube is working into.
A varying impedance in a loudspeaker isn’t typically a problem for a solid state amplifier but for a tube amplifier, that impedance manifests itself as a varying load on the output tube, which in turn causes measurable frequency response aberrations in the amplifier itself. Some of these aberrations contribute to that “tube sound” coloration which some people may find pleasant on some types of recordings. If your philosophy allows for non-neutral sound reproduction, this may be something you might enjoy.
I mention this because your current tweeters have an impedance as shown by the blue line in the graph below:
It’s actually fairly flat and probably isn’t wreaking havoc on your SETs frequency response. A typical compression driver, on the other hand, has an impedance that looks something like the graph on the right:
These impedance variations can be tempered somewhat in the crossover design, whether or not to do it (and to what degree) is something still debated on forums. Most people are running solid state amplification so it stands to reason that most loudspeaker designers wouldn’t waste their time flattening the impedance of a high frequency driver.
I bring all this up to drive home the point that tube amps and loudspeakers interact with each other as a system in much the same way a pair of loudspeakers interact with the room they’re placed in.
If I haven’t scared you away from compression drivers, good, that was not my intention. I have a push-pull tube amp I have used with a loudspeaker kit I built and it sounded fine, impedance peaks and all.
If you would rather build a kit than cut and measure yourself, I would recommend the Fusion 12 (98dB) or Fusion 15 (99dB) kits from diysoundgroup. They aren’t fullrange so you would probably be happier with an active subwoofer. If you can live with a little less sensitivity, there’s also the Maximus 12 design (95dB) from the same website. It would put you 30% over your stated budget and you would also have to build an enclosure for the drivers that sit atop the midbass module.
I hope you don’t mind all the food for thought. Good luck.
Thanks very much for the detailed explanation. I've wondered what makes one speaker "easy on the amplifier" and another one "difficult to drive." If I understand correctly, it's the variance in impedance that causes this; with a smaller amount of change from nominal to maximum impedance being "easier to drive."
One of the options that I was considering was to go with the Faital 15PR400 woofer and the B&C DE250-8 compression tweeter and appropriate horn, and a simple crossover. I figure it shouldn't be that difficult to find a speaker box that is close to the right shape and volume, then replace the baffle with one to house the two drivers.
I was hoping to keep the speaker cabinet fairly narrow, with added depth, but it's harder when you go with larger drivers.
One of the options that I was considering was to go with the Faital 15PR400 woofer and the B&C DE250-8 compression tweeter and appropriate horn, and a simple crossover. I figure it shouldn't be that difficult to find a speaker box that is close to the right shape and volume, then replace the baffle with one to house the two drivers.
I was hoping to keep the speaker cabinet fairly narrow, with added depth, but it's harder when you go with larger drivers.
Your understanding is correct; tubes behave more linearly when the load is constant. Also, in general, tube amplifiers work best with greater nominal loads than lesser ones. This is because a couple ohms of impedance swing on an a nominally 16 ohm load is a smaller percentage than a couple ohms swing on a nominally 4 ohm load. In addition to this, the primary/secondary winding ratio increases greatly when trying to step up a nominal 4 ohm load to a given primary impedance versus an 8- or 16-ohm one. And with increased winding ratio and size comes increased interwinding capacitance and transformer losses, affecting the transformers HF response and efficiency, respectively. So nominally 8 ohm loudspeakers with woofers that dip down to 3 or 4 ohms in their impedance curve can be less than ideal loads for tube amplifiers. It’s even worse with nominally 4 ohm speakers.
I think you’re on the right track, that FaitalPRO is sensitive and the DE250 is commonly used. Are you planning on copying an existing design or are you going to take the plunge into DIY? If you picked something like this the crossover work has been done already.
I think you’re on the right track, that FaitalPRO is sensitive and the DE250 is commonly used. Are you planning on copying an existing design or are you going to take the plunge into DIY? If you picked something like this the crossover work has been done already.
A subwoofer or two may give you what you want. I'd personally go for an active, sealed unit and preferably with some sort of eq.
Thanks for the advice. At this point, I'm kind of weighing all options. I have basic woodworking tools, but I don't really have everything necessary to properly build cabinets from scratch. I do want to stick with a total of two speaker cabinets and I only have room for a cabinet width of about 20 in. I could go with a depth of up to about 30 in, though.
One of the concerns I have about the DIY route is that I can't hear what things sound like until I build it. If the bass is too boomy or the midrange isn't pleasing, I have a real problem. This is one advantage of going with something vintage, in that I can listen to a known piece of music before handing over the cash. Of course, the unknown of how things will sound with my equipment in my room remain.
A sort of happy medium that I am considering is to determine the cabinet volume requirement for the woofer I choose and search for a commercial made speaker cabinet in thrift stores, craigslist, etc that is close and looks nice. I have the equipment to cut the original baffle out of the donor speaker and replace it with a baffle that fits the drivers that I go with. I can dampen the donor cabinet and build a crossover easily in the process.
GM, thanks for the link on Pi. I'll check it out!
One of the concerns I have about the DIY route is that I can't hear what things sound like until I build it. If the bass is too boomy or the midrange isn't pleasing, I have a real problem. This is one advantage of going with something vintage, in that I can listen to a known piece of music before handing over the cash. Of course, the unknown of how things will sound with my equipment in my room remain.
A sort of happy medium that I am considering is to determine the cabinet volume requirement for the woofer I choose and search for a commercial made speaker cabinet in thrift stores, craigslist, etc that is close and looks nice. I have the equipment to cut the original baffle out of the donor speaker and replace it with a baffle that fits the drivers that I go with. I can dampen the donor cabinet and build a crossover easily in the process.
GM, thanks for the link on Pi. I'll check it out!
It looks like I misspoke earlier; the Fusion 12 from DIYSG has an F3 of 40Hz which would be fine for an old school, vinyl-based setup. The Fusion 15 has an F3 of 45Hz. Again, lacking the bottom octave but not really a deal breaker for a lot of material with a turntable based source.
Your apprehension about construction is understood, I felt much the same way. I have to say the DIYSG flatpacks are well cut, well packed, and SUPER easy to assemble. Wood glue, wood filler, clamps & an orbital sander are all that’s really needed to get a solid, square enclosure.
I also understand your apprehension about not being able to audition any of these recommendations. If you can make it to downtown Oakland some time soon, the Blue Bottle Cafe on 9th street is running a pair of Fusion 12s. Those were designed by Jeff Bagby (well respected designer) as are the Maximus 12s mentioned earlier.
Your apprehension about construction is understood, I felt much the same way. I have to say the DIYSG flatpacks are well cut, well packed, and SUPER easy to assemble. Wood glue, wood filler, clamps & an orbital sander are all that’s really needed to get a solid, square enclosure.
I also understand your apprehension about not being able to audition any of these recommendations. If you can make it to downtown Oakland some time soon, the Blue Bottle Cafe on 9th street is running a pair of Fusion 12s. Those were designed by Jeff Bagby (well respected designer) as are the Maximus 12s mentioned earlier.
You're welcome!
Note that ideally you need the amp's output impedance/damping factor [series resistance/Rs] before selecting a speaker alignment as it creates a 'smiley face' EQ curve that is fine for speakers with a tonally balanced rolled off LF, HF, but can sound [incredibly] 'boomy'/'loose' down low combined with a corresponding HF 'shout' with some SETs.
In short, [Rs] can raise the driver's Qts [Qts'] considerably, ditto cab net volume [Vb]: mh-audio.nl - Home
GM
I'm also thinking stereo subs. Look into Rythmik's product line. I DIY sealed boxes for their 12" servo driven kit and works very well. But I think for your case their double 8" servo driven subs are probably better suited. They have a fair amount of flexibility built into their eq and their plate amp will relieve your 300B and your smallish speakers from trying to reproduce lower freqs.
I'm thinking you use the twin 8" cabinet as a stand below your existing bookshelves.
FWIW, I know of a guy with a very tuned system who is running JBL M2 and below them a pair of those twin 8" "subs" as midbasses from 50 to 200Hz, so they play nice well above regular sub range. Below those he uses a pair of 12" Rythmik subs. He has an active system (like mine), though.
If you are in the US I believe Rythmik has a friendly return policy so you can try them in your room.
I hope this helps.
I'm thinking you use the twin 8" cabinet as a stand below your existing bookshelves.
FWIW, I know of a guy with a very tuned system who is running JBL M2 and below them a pair of those twin 8" "subs" as midbasses from 50 to 200Hz, so they play nice well above regular sub range. Below those he uses a pair of 12" Rythmik subs. He has an active system (like mine), though.
If you are in the US I believe Rythmik has a friendly return policy so you can try them in your room.
I hope this helps.
The classic speaker for this amp is an Altec 604E, preferable in a Altec 620 or 612 cabinet. It's not a fullrange speaker, but a dual concentric (2 speakers in one) wich is better for the frequency bandwith.
The originals are very expensive but there is a modern variation of it called the Great Plains Audio 604 wich does the job perfect. It's also not cheap but more reasonable than the original. And plans of those cabinets are easely found online.
For fullrange drivers, you need a driver that has an efficiency of more than 90dB at least, and prefarable above 93dB.
A Lowter DX4 in a ported cabinet could do it and is efficient (96dB on 1m/1w) enough for your amp. It's not cheap altough. Other drivers from this brand may also do it (but i did not hear them, so i can't judge).
An Mark Audio Alpair 10M gen 3 could do it also if you don't want to push it very loud. Those are 88dB efficient (so max volume is about 100dB on 1m for a pair in theory, in reality a few dB lower) wich could be enough for a small room. I did use this speaker in a 13L backside ported box for years and never put my 35w amp over a quarter (and mostly much lower) open in the small appartment living room (4x8x2.5m) where i lived. It had a solid bass till the low 40's, but a bit undefined. That's why i have build some dedicated subs to complement them below 180Hz. The crossover did eat some efficiency altough, and such a config won't work with an 8w amp, you'll need at least double of it. You could use an active crossover (analog or dsp) with the SET feeding the top and an other amp (tube or solid state) feeding the sub altough.
I'm not into fostex fullrange (taste differ they say) but a FE208EZ is also efficient enough (97dB) to do what you want. And there are some more that i don't know but are high efficient like the Seas Prestige FA22RCZ and Seas X1-04 Exotic that are also efficient enough.
And then you've got a whole leap of ridiculous expensive fullrange drivers that are often high efficient like those of Feastrex. But i think that price can't be justified by a rise in quality if you compare to others...
The originals are very expensive but there is a modern variation of it called the Great Plains Audio 604 wich does the job perfect. It's also not cheap but more reasonable than the original. And plans of those cabinets are easely found online.
For fullrange drivers, you need a driver that has an efficiency of more than 90dB at least, and prefarable above 93dB.
A Lowter DX4 in a ported cabinet could do it and is efficient (96dB on 1m/1w) enough for your amp. It's not cheap altough. Other drivers from this brand may also do it (but i did not hear them, so i can't judge).
An Mark Audio Alpair 10M gen 3 could do it also if you don't want to push it very loud. Those are 88dB efficient (so max volume is about 100dB on 1m for a pair in theory, in reality a few dB lower) wich could be enough for a small room. I did use this speaker in a 13L backside ported box for years and never put my 35w amp over a quarter (and mostly much lower) open in the small appartment living room (4x8x2.5m) where i lived. It had a solid bass till the low 40's, but a bit undefined. That's why i have build some dedicated subs to complement them below 180Hz. The crossover did eat some efficiency altough, and such a config won't work with an 8w amp, you'll need at least double of it. You could use an active crossover (analog or dsp) with the SET feeding the top and an other amp (tube or solid state) feeding the sub altough.
I'm not into fostex fullrange (taste differ they say) but a FE208EZ is also efficient enough (97dB) to do what you want. And there are some more that i don't know but are high efficient like the Seas Prestige FA22RCZ and Seas X1-04 Exotic that are also efficient enough.
And then you've got a whole leap of ridiculous expensive fullrange drivers that are often high efficient like those of Feastrex. But i think that price can't be justified by a rise in quality if you compare to others...
Consider Faital 15PR400 and HF108.
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I have the Faital HF108 1" compression driver and believe it would musically cover the 900-1000Hz crossover in an SEOS15 required by the Faital 15PR400. The impedance curve is very flat above the 670Hz resonance. Download the datasheet impedance graph, and model how this simplifies a passive crossover.
Many classic high efficiency 2-way designs use BW3 circuits on both the 15PR400 and HF108.
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For the large physical=time difference between the woofer and horn, there is good science behind using “quasi-optimal” BW3/BW3 crossovers which slight variations in crossover frequency to better align the mid-tweet phase.
3rd order Butterworth Low Pass, -3dB @ Fx*0.87 (+)
3rd order Butterworth High Pass, -3dB @ Fx*1.15 (-)
Time Offset = 0.22*c/Fx
----
I have the Faital HF108 1" compression driver and believe it would musically cover the 900-1000Hz crossover in an SEOS15 required by the Faital 15PR400. The impedance curve is very flat above the 670Hz resonance. Download the datasheet impedance graph, and model how this simplifies a passive crossover.
Many classic high efficiency 2-way designs use BW3 circuits on both the 15PR400 and HF108.
-------
For the large physical=time difference between the woofer and horn, there is good science behind using “quasi-optimal” BW3/BW3 crossovers which slight variations in crossover frequency to better align the mid-tweet phase.
3rd order Butterworth Low Pass, -3dB @ Fx*0.87 (+)
3rd order Butterworth High Pass, -3dB @ Fx*1.15 (-)
Time Offset = 0.22*c/Fx
excellent, and I have a follow-up ?
Excellent information, as usual from you, Mr. Linesource. Is the SEOS 15/HF-108 combination really that much deeper than the acoustic center of the PR400 ? Just a few inches, I would imagine (?) The real question is, could not the drivers be physically mounted such that the offset is accounted for ? What if said woofer was mounted behind the front baffle plate ?
Excellent information, as usual from you, Mr. Linesource. Is the SEOS 15/HF-108 combination really that much deeper than the acoustic center of the PR400 ? Just a few inches, I would imagine (?) The real question is, could not the drivers be physically mounted such that the offset is accounted for ? What if said woofer was mounted behind the front baffle plate ?
@brinkman, thanks for the info. I'm in the South Bay, so Oakland isn't too far away from me. Looks like both of the Fusion kits are out of stock. I'll contact them to see what's up with that.
@waxx Yeah, I had considered the 604's, but man they are spendy. I may come back to them. I recently passed up an opportunity to grab a pair of vintage Wharfdale 15" coaxial drivers. They were in real bad shape, unfortunately. I've been considering coming back to them, but one of them needs a complete recone of the woofer, which I'm afraid would leave them sounding different.
@LewinskiH01 I'm trying to stick with only 2 speaker cabinets, as I have a pretty small room. It's more-or-less 10' X 10' I actually have a pair of Phillips 567 Electronic powered speakers. I set them up to serve as powered subwoofers, but they are super boomy in the bass department.
@LineSource Thanks for the information. I'll check out the HF108. I did look at some of their HF drivers, and I'm certainly not married to the DE250. Ah yeah. Crossover design. I hadn't even got there yet. Is there a recommended crossover calculator? I've been using the DIY Audio and Video calculators in my research.
@waxx Yeah, I had considered the 604's, but man they are spendy. I may come back to them. I recently passed up an opportunity to grab a pair of vintage Wharfdale 15" coaxial drivers. They were in real bad shape, unfortunately. I've been considering coming back to them, but one of them needs a complete recone of the woofer, which I'm afraid would leave them sounding different.
@LewinskiH01 I'm trying to stick with only 2 speaker cabinets, as I have a pretty small room. It's more-or-less 10' X 10' I actually have a pair of Phillips 567 Electronic powered speakers. I set them up to serve as powered subwoofers, but they are super boomy in the bass department.
@LineSource Thanks for the information. I'll check out the HF108. I did look at some of their HF drivers, and I'm certainly not married to the DE250. Ah yeah. Crossover design. I hadn't even got there yet. Is there a recommended crossover calculator? I've been using the DIY Audio and Video calculators in my research.
One thing that i have not seen mentioned is that with the highish output impedance of a 300B SET (i have heard a reactance drive 45 which was outstanding), a flattish impedance curve is often more important than the ultimate efficiency. This is where a good FR can shine, and be synergistic with the 300B SET.
1st driver that comes to mind is the Alpair 10p.
The Vifas have a bit of a plasticy sound as part of their nature. Their low-level resolution(ie DDR) is not all that good.
Also, do not rule out building a T-Line or a horn. It is often easier to build them than some small standmounts (ie the A10p in FHXL is superb).
dave
1st driver that comes to mind is the Alpair 10p.
The Vifas have a bit of a plasticy sound as part of their nature. Their low-level resolution(ie DDR) is not all that good.
Also, do not rule out building a T-Line or a horn. It is often easier to build them than some small standmounts (ie the A10p in FHXL is superb).
dave
Thanks for the confirmation on the "plasticy" sound on the Vifas. I was beginning to think it was just me. 😕 I did strongly consider going with a TL speaker design and full range driver, possibly with the addition of a tweeter. Unfortunately, my woodworking skill level and available tools make this pretty challenging for me.
I pulled the trigger on a pair of Faital Pro HF201's. The price was right, so it made sense to end my search here. I think I will go with the Faital Pro 15PR400 woofer to pair with them. Looks like I am going full DIY, but I believe I have the skill and tools to build a basic box cabinet. From reading other threads, it seems like the 15PR400 wants around a 150 liter volume cabinet.
Here are plans for one of the most popular FR TLs out there. Tell me where (other than large panels) this is any harder than a standard BR box?
http://frugal-phile.com/boxlib/pensils/Pensil103-plan-300114.pdf
dave
Interesting. I was looking at ~8" full range drivers and it seemed (apparently incorrectly) that I needed to be around a 20' TL, which is a pretty complicated box for me to build.
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