I just finished a speaker project but now I am thinking of the next, this time designing myself. I was thinking of a 2.5-way speaker with closed cabinet. This woofer might be a good choice since I want to make a rather cheap speaker: Europe Audio
Then I need to find a good cheap tweeter. My thought was to build a floorstander, narrow and about 1 meter high. This speaker should be compact to use as a TV speaker to avoid those awful built in TV speakers.
Closed cabinet to make them easy to place and to build.
Then I need to find a good cheap tweeter. My thought was to build a floorstander, narrow and about 1 meter high. This speaker should be compact to use as a TV speaker to avoid those awful built in TV speakers.
Closed cabinet to make them easy to place and to build.
Thanks, I have been looking at those, I will have a look tonight trying to figure out what will suit the woofer best. I have to learn a lot, but from what I know if you use 2 woofers in a 2.5-way you get 3dB more sensitivity so since the woofer is about 88dB sensitivity the tweeter should at least be 88+3=91dB, right?
While the gain for two drivers running in parallel is 6dB, you are completely forgetting the baffle step effect. This should give you a loss of 6dB at low frequencies, while retaining the nominal sensitivity at high fr. Here Low and High are in terms of the baffle width.
The normal approach of a x.5 design is to completely compensate for this baffle effect, in which one of the woofer runs "full-range" and the other (the .5 woofer) has a 1st order low pass centered at the baffle step frequency. See for example: ZDT3.5
As for the tweeter's choice, using a 6.5" mid-woofer, I'd opt for a tweeter able to be crossed at 2KHz LR4. A Vifa DX25 should be able to do that. For a higher price there are the Seas 27TDFC or 27TBFC/G.
Ralf
The normal approach of a x.5 design is to completely compensate for this baffle effect, in which one of the woofer runs "full-range" and the other (the .5 woofer) has a 1st order low pass centered at the baffle step frequency. See for example: ZDT3.5
As for the tweeter's choice, using a 6.5" mid-woofer, I'd opt for a tweeter able to be crossed at 2KHz LR4. A Vifa DX25 should be able to do that. For a higher price there are the Seas 27TDFC or 27TBFC/G.
Ralf
Thanks giralfino, like I said I have some learning to do. I have read somewhere about that way to compensate for the baffle step and my intention is do it like that.
I want a tweeter that is rather cheap but at the same quality level as the woofers. Hope this is possible.
I want a tweeter that is rather cheap but at the same quality level as the woofers. Hope this is possible.
I think I am choosing between the Vifa DX25 or Seas 27TDFC. Best choice for a simple crossover work? Should be the Seas? What do you think?
I am not too impressed with the frequency response of this driver. 😡
The resonance at ~5kHz is visable also in the off axis responses and my experience is that one can hear this in some extent.
Hi EngelholmAudio. Yes I have seen that and maybe it will be problematic. However it should be possible to remove it with the crossover, I think they did that with the "Tarkus", se link above. The woofer is very cheap at the moment at that dealer, maybe because of the problems you mentioned.
I don't have first hand experience with either drivers, but I think that both can be used with a 2KHz LR4. The Seas can go a bit lower though. The hard part for the crossover is in the woofer part, with the 5KHz breakup, but as seen in the Tarkus project, you have a starting point.
Ralf
I am leaning towards using just one woofer, I think it will be enough for a TV speaker, it will also keep the cost down. Since this is a learning project I want it to be cheap and then if I succeed sell the speakers to someone.
Fountek FW168, aluminium cone, very well manufactured, low distortions, tested by Zaph:
Zaph|Audio
a few € more than the peerless but if you are able to create a well designed filter they will make a highly accurate speaker.
Available here in EU:
PLUS - Elektronik Lautsprecher & Elektronik - Onlineshop
Haut-parleur 16 cm Fountek FW168 (8 ohm)😉
Now I have decided for these drivers: H1189-06 27TDFC or
http://www.europe-audio.com/document.asp?document_id=1746&link=datasheets\peerless\DX25TG09-04.pdf
and:
H1215-08 CA18RNX
Comments on this? It will be a 2-way bass reflex speaker I will try to build for a friend of mine. I want the port forward to enable use close to back wall if necessary.
The woofer seem to have a rather low sensitivity, maybe a problem when BFC is done if I want sensitivity at least 87dB?
These woofers (4 different): http://www.europe-audio.com/document.asp?document_id=2314&link=datasheets\scanspeak\18w-8424g00.pdf
Any experience from those?
http://www.europe-audio.com/document.asp?document_id=1746&link=datasheets\peerless\DX25TG09-04.pdf
and:
H1215-08 CA18RNX
Comments on this? It will be a 2-way bass reflex speaker I will try to build for a friend of mine. I want the port forward to enable use close to back wall if necessary.
The woofer seem to have a rather low sensitivity, maybe a problem when BFC is done if I want sensitivity at least 87dB?
These woofers (4 different): http://www.europe-audio.com/document.asp?document_id=2314&link=datasheets\scanspeak\18w-8424g00.pdf
Any experience from those?
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Your last list consist of drivers that are 2x or more expensive than your first choice. Nothing wrong with that, but you should first set a price goal and then ask for advice.
The CA18RNX + 27TDFC combo sounds good, and SEAS itself published a design: Mimir
IMHO I wouldn't use the XT25 with a 6.5" mid-bass because this tweeter should be used with an higher crossover point that most 6.5" driver are able to hold without beaming. Some designers think that the XT25 should be used from 3K Hz. Check Zaph site for specs and mini-review: tweetermishmash
I don't have experience with the 18W8424 driver but Zaph tested the "brother" 18W8434 (bigger voice coil I think) and seems to quite like it: Zaph|Audio blog. A speaker with a 18W84x4 and the 27TDFC should be a good project.
Last thing is about the port (and speaker) placement. A port doesn't need big space to operate correctly, 20 cm are enough. The problem is that if you place a speaker less than 20 cm near the wall you'll have more bass than designed and a not good midrange. The first problem can be avoided designing for a BSC less than 6dB, but you don't have a solution for the second problem, as it arises from a sum of direct and reflected sound. Depending on the frequency, the sum can be in or out of phase, and if the wall is near the speaker, the reflected sound isn't too less in SPL in respect to the direct sound, so it is not negligible. You could place damping material, but for low (and mid) frequencies no material is really effective in absorbing the sound without big thickness.
Ralf
The CA18RNX + 27TDFC combo sounds good, and SEAS itself published a design: Mimir
IMHO I wouldn't use the XT25 with a 6.5" mid-bass because this tweeter should be used with an higher crossover point that most 6.5" driver are able to hold without beaming. Some designers think that the XT25 should be used from 3K Hz. Check Zaph site for specs and mini-review: tweetermishmash
I don't have experience with the 18W8424 driver but Zaph tested the "brother" 18W8434 (bigger voice coil I think) and seems to quite like it: Zaph|Audio blog. A speaker with a 18W84x4 and the 27TDFC should be a good project.
Last thing is about the port (and speaker) placement. A port doesn't need big space to operate correctly, 20 cm are enough. The problem is that if you place a speaker less than 20 cm near the wall you'll have more bass than designed and a not good midrange. The first problem can be avoided designing for a BSC less than 6dB, but you don't have a solution for the second problem, as it arises from a sum of direct and reflected sound. Depending on the frequency, the sum can be in or out of phase, and if the wall is near the speaker, the reflected sound isn't too less in SPL in respect to the direct sound, so it is not negligible. You could place damping material, but for low (and mid) frequencies no material is really effective in absorbing the sound without big thickness.
Ralf
Thanks Ralf, good comments. My concern with the Seas CARNX is rather low sensitivity, I want it to be a rather easy load for the amp. Probably best is to use a 2.5-way to get better sensitivity but the price gets too high then. I am rather sure I will use the Vifa DX25 since it is cheap and according to many sounds good. I now just need a 6.5 inch woofer that is rather sensitive to match. I am not sure if I should go vented or sealed yet.
Go to an easy load rather high sensitivity. 85dB of sensitivity is not so bad.
I think a 27TDC is a better match with a CA18RNX than a DX25, a good tweeter too. The mimir kit is a good advice. SEAS is a good manufacturer of speaker.
If you want a lower price kit, you also have
Links
If you want better sound,very affordable, look at this 3 ways : Tarkus - undefinition
I think a 27TDC is a better match with a CA18RNX than a DX25, a good tweeter too. The mimir kit is a good advice. SEAS is a good manufacturer of speaker.
If you want a lower price kit, you also have
Links
If you want better sound,very affordable, look at this 3 ways : Tarkus - undefinition
Maybe it's time to recap.
Vented vs closed. That should be your first thing to consider, because choosing one configuration can eliminate some drivers. Not many 6.5" drivers are best suited for a closed box (there was a discussion about that some time ago here, see http://www.diyaudio.com/forums/multi-way/195444-6-5-7-midwoofer-sealed-enclosure.html). Two drivers come to mind that work good in a closed box: a Seas CA18RLY and a Dayton RS180. Also the Peerless 830657 can be used in a closed box.
Placement. Putting a box near the wall is always a bad thing, but in case you have to, don't use a x.5 speaker configuration, because it is by design a full BSC, so at the end you'll have to much bass.
Price (woofer). The Peerless 830657 is hard to beat, and in the Tarkus project I pointed some posts ago there is IMHO a good crossover that address also the breakup of the driver (in this respect I'm suspicious about the other project suggested by jerome69). The Tarkus crossover can be a starting point in case you'll use the 830657. For a higher price there are lot of possibilities.
Price (tweeter). The DX25 has probably a good price/performance ratio and can work also at 2KHz. The 27TDFC costs more but works also better.
Design or not. If you want to try to design yourself, then choose a "simple" woofer (the Seas and the SS Discovery).
Ralf
Vented vs closed. That should be your first thing to consider, because choosing one configuration can eliminate some drivers. Not many 6.5" drivers are best suited for a closed box (there was a discussion about that some time ago here, see http://www.diyaudio.com/forums/multi-way/195444-6-5-7-midwoofer-sealed-enclosure.html). Two drivers come to mind that work good in a closed box: a Seas CA18RLY and a Dayton RS180. Also the Peerless 830657 can be used in a closed box.
Placement. Putting a box near the wall is always a bad thing, but in case you have to, don't use a x.5 speaker configuration, because it is by design a full BSC, so at the end you'll have to much bass.
Price (woofer). The Peerless 830657 is hard to beat, and in the Tarkus project I pointed some posts ago there is IMHO a good crossover that address also the breakup of the driver (in this respect I'm suspicious about the other project suggested by jerome69). The Tarkus crossover can be a starting point in case you'll use the 830657. For a higher price there are lot of possibilities.
Price (tweeter). The DX25 has probably a good price/performance ratio and can work also at 2KHz. The 27TDFC costs more but works also better.
Design or not. If you want to try to design yourself, then choose a "simple" woofer (the Seas and the SS Discovery).
Ralf
I want to design myself trying to learn as much as possible, I will buy a microphone to be able to measure, I have Holmimpulse on my computer (not sure what it does lol), what do I need? can I use the sound card in my computer or do I need something else? I know of a program called Basta! (swedish) the demo version, been playing around with it a little.
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