Say you had a 1.5 watt 45 SET tube amp, and were planning a high efficiency speaker like the Econowave or SEOS designs, using a 15” woofer & compression driver, aiming for a woofer that was rated at least 100dB. Assume one of the woofers that have a frequency range that is rated up to 4KHz, 4.2 or 4.8KHz. Size & WAF not an issue but high sensitivity is.
Is it better to have a high crossover point at 3.5 KHz where the 15” driver is reproducing most of the midrange around 1k-4k? Here the benefit is the midrange would not be attenuated.
Or is it better to have a low crossover like at 900Hz, 1KHz or 1.6KHz where the compression driver is handling most of the midrange between 1k-4k? But that usually means the midrange is being attenuated, as most compression drivers need 5-10dB of attenuation to match the woofer.
I am mainly wondering if it sounds better to have the midrange reproduced by the compression driver, even if it needs several dB of attenuation, from those who have experience.
Or since the speaker would be used with a 1.5W SET, should a focus be on matching a drivers so no attenuation is needed, regardless of where the crossover would be? if the woofer and compression driver did match in sensitivity and did not require any attenuation, would it be most people’s preference to choose a crossover point that had the woofer or compression driver reproducing the midrange? Thanks for any input.
Is it better to have a high crossover point at 3.5 KHz where the 15” driver is reproducing most of the midrange around 1k-4k? Here the benefit is the midrange would not be attenuated.
Or is it better to have a low crossover like at 900Hz, 1KHz or 1.6KHz where the compression driver is handling most of the midrange between 1k-4k? But that usually means the midrange is being attenuated, as most compression drivers need 5-10dB of attenuation to match the woofer.
I am mainly wondering if it sounds better to have the midrange reproduced by the compression driver, even if it needs several dB of attenuation, from those who have experience.
Or since the speaker would be used with a 1.5W SET, should a focus be on matching a drivers so no attenuation is needed, regardless of where the crossover would be? if the woofer and compression driver did match in sensitivity and did not require any attenuation, would it be most people’s preference to choose a crossover point that had the woofer or compression driver reproducing the midrange? Thanks for any input.
Before we try and explain, you might want to read up on beaming and cone break up. Once you understand those two it will give you a better idea of what compromises you are willing to accept. The combo you are proposing is more suited to PA duty than critical listening for reasons you will come to understand. After that, come back and ask questions.
Cheers.
Cheers.
With a single ended 45 amp and not biamping you should consider a 2-way horn with a 10 or 12" bass driver loaded in a front hypex or expo horn and either a 1.5 or 1" compression driver crossed over between 500 and 800 cycles. A compression tweeter may be added to add to the top end and subwoofers for the low bass. Fully horn loaded you may actually have enough head room in the system to be satisfied with the 45 output tube.
Sorry to say it this way but -
If ducks were gorillas would it be better to feed them bananas or bread crumbs?
Well the answer is, it doesn't matter because Duck are NOT Gorillas, and you do not, at least not very likely, have a 15 woofer that is functional to 4khz or more.
Yes, the frequency response might be rated at 4khz (or more) but that does not mean that is within the practical working range of the woofer. Few woofer, even must smaller woofer, are functional above 2khz or there about. And the preferred functioning range is probably around 1khz or less.
Next, a hypothetical woofer and a hypothetical compression driver are capable of 500db, and any crossover. But fantasy is not reality.
As to the midrange/highs being attenuated, they are only attenuated, in my understanding, to bring them down to the level of the woofer. So, I'm not clear on what you mean here.
The only meaningful response can be relative to real drivers. Tell use what drivers you are considering and give us a better idea of the application, and those here in-the-know, can response with something you can actually use.
Or, explain your project requirements and use in detail, and likely someone here knows of a good project to fill those requirements.
I see no point in speculating on hypothetical fantasy because those fantasies are never going to translate into reality. Far better for focus on reality, because that will lead to actual reality when translated into a speaker.
The general rule is - let each driver do what it does best.
So -
- Either give us an example with real drivers, or potential drivers, under consideration.
- Or, give us the details on the design concept, and let the members here recommend speakers and/or projects that fill those requirements.
But then ... that's just my opinion.
Steve/bluewizard
If ducks were gorillas would it be better to feed them bananas or bread crumbs?
Well the answer is, it doesn't matter because Duck are NOT Gorillas, and you do not, at least not very likely, have a 15 woofer that is functional to 4khz or more.
Yes, the frequency response might be rated at 4khz (or more) but that does not mean that is within the practical working range of the woofer. Few woofer, even must smaller woofer, are functional above 2khz or there about. And the preferred functioning range is probably around 1khz or less.
Next, a hypothetical woofer and a hypothetical compression driver are capable of 500db, and any crossover. But fantasy is not reality.
As to the midrange/highs being attenuated, they are only attenuated, in my understanding, to bring them down to the level of the woofer. So, I'm not clear on what you mean here.
The only meaningful response can be relative to real drivers. Tell use what drivers you are considering and give us a better idea of the application, and those here in-the-know, can response with something you can actually use.
Or, explain your project requirements and use in detail, and likely someone here knows of a good project to fill those requirements.
I see no point in speculating on hypothetical fantasy because those fantasies are never going to translate into reality. Far better for focus on reality, because that will lead to actual reality when translated into a speaker.
The general rule is - let each driver do what it does best.
So -
- Either give us an example with real drivers, or potential drivers, under consideration.
- Or, give us the details on the design concept, and let the members here recommend speakers and/or projects that fill those requirements.
But then ... that's just my opinion.
Steve/bluewizard
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Thanks for the responses so far. Mainly I am interested in building a pair of DIY speakers that would have the sensitivity a 1.5 watt SET tube amp would require. From what I gather that would be around 100dB or even more. Trying to sort through the many DIY plans has taken a lot of reading. I am not committed to any specific speaker type and could use some help narrowing down a list of projects that may already exist that I am not aware of. It would be for music, critical listening/home audio use, not home theater user, budget around $700 or thereabouts, max $1,000.
Neither, Some Horn Magic is Needed
Horn Loaded (Compression) driver design trades bandwidth for efficiency.
If you choose to use wimpy amps then an all-horn system will meet mission requirements, but it will need to be 3-way.
Strangly, the midrange will be the biggest challange.
Idealy you do not want to carve up the speach range. 200-300 Hz to 2,000-3,000 Hz.
Use the set amp you have for the top end only.
Regards,
WHG
Horn Loaded (Compression) driver design trades bandwidth for efficiency.
If you choose to use wimpy amps then an all-horn system will meet mission requirements, but it will need to be 3-way.
Strangly, the midrange will be the biggest challange.
Idealy you do not want to carve up the speach range. 200-300 Hz to 2,000-3,000 Hz.
Use the set amp you have for the top end only.
Regards,
WHG
My budget of $700 is for drivers, not including cabinet wood/binding posts. Here is one combination I was looking at. The EighteenSound 15MB700 15" woofer Eighteen Sound Speakers - 18 Sound - Eighteen Sound 15MB700 - Eighteen Sound 15MB700 15" midbass 400 watt AES speaker. Eighteen Sound 15MB700 midbass speakers are available here. 18 Sound speaker components. and the Celestion CDX1-1415 compression driver Celestion CDX1-1415 Neo 1" Compression Driver 20W 294-2130 with crossover at 2.5K. An alternate compression driver would be the Dayton Audio D250-P Dayton Audio D250P-8 1" Polyimide Compression Horn Driver 270-402 as both the compression drivers are rated at 104dB while the woofer is 103dB. I was thinking a tube amp would benefit from no attenuation matching this way. Also I have a powered subwoofer that could be added in at 150Hz if a two way speaker were designed with the components above.
Sadly,
The woofer you linked to will not be 103 dB in a box.
At some frequency, it will become somewhere between 97 and 100 dB because of "baffle step". So you are going to have to pad your tweeter down between 4 and 7 dB to compensate, or put up with the thin base response.
You can actually see it on the frequency response chart the manufacture provides.
Notice how it slops down starting at 300 Hz?
HTH
Doug
The woofer you linked to will not be 103 dB in a box.
At some frequency, it will become somewhere between 97 and 100 dB because of "baffle step". So you are going to have to pad your tweeter down between 4 and 7 dB to compensate, or put up with the thin base response.
You can actually see it on the frequency response chart the manufacture provides.
Notice how it slops down starting at 300 Hz?
HTH
Doug
We know more, but I still don't think you are providing sufficient context.
First -
WHY?
Why this particular combination? Why only a 1.5w amp?
Most speakers, in general, can be driver to 90dB with about 1 watt, however, to drive the same speaker to 93dB takes 2 watts, and to 96dB takes 4 watts, and 99dB takes 8 watts. To reach 102dB takes 16 watts.
Next, while certainly not impossible, you will have a hard time finding a woofer with 100dB output. At least not a Sensitivity rating.
Next, do you expect to sustain 100dB or just peak at 100dB?
My speaker are rated at 90dB, I have no problem reaching 100dB peaks and above, but I'm using a 100w/ch amp with speakers that have 2x 8" woofers each.
If you are going for ultra-high output on the bass driver, then you are likely going to need a front horn load, horn loaded port, of a large transmission line design.
The Eighteen Sound Woofer linked to by JamesDB has the output you need, but they are $500 per pair. That is half your budget, and you don't have mid, high, crossovers, cabinets, or misc components.
To get the efficiency from the woofer though, you are going to need a pretty large cabinet. Do you have room for such a cabinet.
Just to give you an idea of the size speaker we are talking about, take a look at these for inspiration -
Everest DD67000 Floorstanding Loudspeaker | JBL Synthesis
Everest DD65000 Floorstanding Loudspeaker | JBL Synthesis
S3900 Floorstanding Speaker | JBL Synthesis
K2 S9900 Floorstanding Speaker | JBL Synthesis
The twin bass driver 3-way models (DD6700) have 96dB/1w/1m, where as the single bass driver model (K2 S9900) has 93dB/1w/1m. (1 watt at 1 meter)
If you don't just want peaks in the +100dB range, if you actually want to sustain that level, then you are going to need some very large speakers indeed.
But also consider, that if you are cruising in the 85dB to 90dB range with peaks in the roughly 100dB range, you are pretty loud. For me, I might hit that during an Action Movie, but that is way too loud for music.
Next, 100dB at the speaker is very different than 100dB at the prime seating location. If I recall correctly, the sound level drops by 6dB every time the distance between the speaker and the listener doubles. So, 100dB at your seat, probably means 110dB at the speaker. But again, that is near a painfully loud level. 90dB is far more realistic.
So, again, it depends on what you mean by 100dB in the functional sense.
Just a thought.
Steve/bluewizard
First -
WHY?
Why this particular combination? Why only a 1.5w amp?
Most speakers, in general, can be driver to 90dB with about 1 watt, however, to drive the same speaker to 93dB takes 2 watts, and to 96dB takes 4 watts, and 99dB takes 8 watts. To reach 102dB takes 16 watts.
Next, while certainly not impossible, you will have a hard time finding a woofer with 100dB output. At least not a Sensitivity rating.
Next, do you expect to sustain 100dB or just peak at 100dB?
My speaker are rated at 90dB, I have no problem reaching 100dB peaks and above, but I'm using a 100w/ch amp with speakers that have 2x 8" woofers each.
If you are going for ultra-high output on the bass driver, then you are likely going to need a front horn load, horn loaded port, of a large transmission line design.
The Eighteen Sound Woofer linked to by JamesDB has the output you need, but they are $500 per pair. That is half your budget, and you don't have mid, high, crossovers, cabinets, or misc components.
To get the efficiency from the woofer though, you are going to need a pretty large cabinet. Do you have room for such a cabinet.
Just to give you an idea of the size speaker we are talking about, take a look at these for inspiration -
Everest DD67000 Floorstanding Loudspeaker | JBL Synthesis
Everest DD65000 Floorstanding Loudspeaker | JBL Synthesis
S3900 Floorstanding Speaker | JBL Synthesis
K2 S9900 Floorstanding Speaker | JBL Synthesis
The twin bass driver 3-way models (DD6700) have 96dB/1w/1m, where as the single bass driver model (K2 S9900) has 93dB/1w/1m. (1 watt at 1 meter)
If you don't just want peaks in the +100dB range, if you actually want to sustain that level, then you are going to need some very large speakers indeed.
But also consider, that if you are cruising in the 85dB to 90dB range with peaks in the roughly 100dB range, you are pretty loud. For me, I might hit that during an Action Movie, but that is way too loud for music.
Next, 100dB at the speaker is very different than 100dB at the prime seating location. If I recall correctly, the sound level drops by 6dB every time the distance between the speaker and the listener doubles. So, 100dB at your seat, probably means 110dB at the speaker. But again, that is near a painfully loud level. 90dB is far more realistic.
So, again, it depends on what you mean by 100dB in the functional sense.
Just a thought.
Steve/bluewizard
In basic, practical terms - you can do pretty well with a SET 45 driving a 15" + horn. Alright for most listening in a reasonable room. I've heard it done in a large room. With a horn as wide as the cabinet, say 17-18" you can cross at 1600Hz no problem. You just want a woofer that is comfortable up there. The old Altec 515 or 416 are my personal choice, but there may be modern drivers that can do as well. I've heard some of the Celestion neo drivers with polymer 'frams and they are very nice indeed. Have not heard the model you listed.
Not sure you can do it for $700, tho.
Not sure you can do it for $700, tho.
James,
Have you worked through what min-max frequency you want the horn to control the polar pattern in your room? Discussions on controlled directivity, uniform directivity, and room interaction present audio illusion options.
A large size horn can remove more room ambience effects heard by the listener. Some listeners in some rooms like this "hear what the microphones heard", e.g. a Synergy horn controls 300-20KHz and can add bass down to 50Hz. Some listeners in some rooms like to add some room ambience to create an audio illusion approaching "hear what someone at the performance heard", e.g. a Geddes OS waveguide covers 800-20Khz and pushes significant midrange energy into the room to generate ambience(similar to your design ideas).
Dr. Geddes website has a paper on controlled directivity. Wayne's PiSpeaker website has a paper on uniform directivity.
For the love of dynamics, a modest speaker budget with a 1.5W amp might accept a 2" compression driver with a large midrange horn, and just add in a "crazy tweeter" with little concern for high-freq lobing from the large C-to-C distance.
For the love of dynamics, a large speaker budget with a 1.5W amp might use a BMS coaxial compression driver with a large horn, or a Synergy horn properly controlling 400-20Khz.
Have you worked through what min-max frequency you want the horn to control the polar pattern in your room? Discussions on controlled directivity, uniform directivity, and room interaction present audio illusion options.
A large size horn can remove more room ambience effects heard by the listener. Some listeners in some rooms like this "hear what the microphones heard", e.g. a Synergy horn controls 300-20KHz and can add bass down to 50Hz. Some listeners in some rooms like to add some room ambience to create an audio illusion approaching "hear what someone at the performance heard", e.g. a Geddes OS waveguide covers 800-20Khz and pushes significant midrange energy into the room to generate ambience(similar to your design ideas).
Dr. Geddes website has a paper on controlled directivity. Wayne's PiSpeaker website has a paper on uniform directivity.
For the love of dynamics, a modest speaker budget with a 1.5W amp might accept a 2" compression driver with a large midrange horn, and just add in a "crazy tweeter" with little concern for high-freq lobing from the large C-to-C distance.
For the love of dynamics, a large speaker budget with a 1.5W amp might use a BMS coaxial compression driver with a large horn, or a Synergy horn properly controlling 400-20Khz.
LineSource, I really don't have experience designing speaker systems or crossovers. I love the look of the BD-Desgn Oris horns and the Avante Garde horns, but they are way above my budget, so I was thinking about something similar but not exact clones. I saw the Tractrix & LeCleach AutoTech horns here, Auto-Tech horns DIY Sound Group and was thinking of a possible two way using a 15" & compression driver with horn supplemented by a powered subwoofer.
If you are going to supplement with a powered subwoofer anyway what's the point of going with a 15"? As you have already said, you don't have crossover design experience, your budget is somewhat limited and you want to use a low powered amp, within those constraints if you want to get up and running why not the SEOS Tempest? It's 98dB sensitivity should be fine. By all accounts it's quite special.
Charles, no I had not , but I think 4 of them may be above my budget. My idea was a 2 way 15" and compression driver probably augmented by a powered subwoofer with a crossover between 900Hz & 1.6KHz. I was thinking since a 45 is only about 1.5W that getting a woofer & compression driver which match closely so L-Pad attenuation is not needed, would avoid resistors in the crossover to avoid power loss.
Octavia, I will look at the SEOS Tempest again, I was not sure if 98dB would be enough for a 45 SET as most recommendations left me thinking it needed to be closer to 100dB. But since you mention it, there are some 15" woofers that have a frequency response low enough that I wonder if a subwoofer would be needed since this speaker would be strictly dedicated for music. Like the Faital Pro 15PR400 100dB 35Hz-4KHz and Fs=32Hz if used with a compression driver and a crossover at 1.6KHz, could be suitable for music without a subwoofer added?
To get the best out of my 45 amps I use 107 db/watt/meter speakers or biamp where the 45 just is used for the treble. 100 db sensitivity is nearly impossible to obtain wide bandwith without multiple drivers, 1/8th space mounting or horns. 100 db sensitive speakers seem to work best with ayt least 15 or more watts like PP el84 or 300B amps The 45 is special but does require special speakers and in my experience direct radiator horn combinations don't give you the magic the tube has, it may hint at it but isn't were you want to be if you want the full experience of the 45.
Luke, Luke.... use the FORCE!
James, James.... use the ROOM!
Seriously, you can get bass frequency gain by putting your speaker against a rear wall. You can get maximum room gain over the widest frequency range if you can put your speakers into the corners.
Wayne's tread on uniform directivity and his pispeakers website have good info on corner speakers.
Download these simple to use simulators and see how you can use your room gain. You only have 1.5 watts and $1000. Moving some furniture is free.
Baffle Edge Diffraction Simulator
By Jeff Bagby Version 1.20
Room Response Calculator v0.6d
By Yavuz Aksan
P.S. When you run the 18 Sound 15MB700 T/S parameters through an efficiency calculator it is a 93.4 db/watt speaker, just as shown on the 18 Sound SPL graph in the low frequency range.
P.S. P.S. Check your local Craig's list for Altec 604 coaxial speakers. I often see good older pairs for ~$1000. This is a well respected 98db/watt speaker. The GPAaudio website has a modern copy($1400/pair) plus SPL graphs.
James, James.... use the ROOM!
Seriously, you can get bass frequency gain by putting your speaker against a rear wall. You can get maximum room gain over the widest frequency range if you can put your speakers into the corners.
Wayne's tread on uniform directivity and his pispeakers website have good info on corner speakers.
Download these simple to use simulators and see how you can use your room gain. You only have 1.5 watts and $1000. Moving some furniture is free.
Baffle Edge Diffraction Simulator
By Jeff Bagby Version 1.20
Room Response Calculator v0.6d
By Yavuz Aksan
P.S. When you run the 18 Sound 15MB700 T/S parameters through an efficiency calculator it is a 93.4 db/watt speaker, just as shown on the 18 Sound SPL graph in the low frequency range.
P.S. P.S. Check your local Craig's list for Altec 604 coaxial speakers. I often see good older pairs for ~$1000. This is a well respected 98db/watt speaker. The GPAaudio website has a modern copy($1400/pair) plus SPL graphs.
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