tcpip said:
Then a MTMMM is the way to going with the bottom two bass
units used as the 0.5 way drivers. Unless you build the speakers
into the wall baffle step will cause midrange problems and close
to wall mounting of speakers causes uneven bass in room.
If your LR4 does not account for driver offsets its possible that
a TMMMM 2.5 way would be just as good as a MTMMM 2.5 way.
a TMMMM 2 way with no BSC is not a good idea IMO, the c/o
frequency is too high for the line array of bass / mid drivers.
sreten.
Can you please elaborate? How do I use the two bottom units as 0.5-way drivers?sreten said:
No, my LR4 does not account for driver offsets.
I think I understand what you're saying... I guess you're referring to the comb filtering that will happen between the tweeter and the lower-placed bass drivers.
Semi-OT: Peerless codes
. The factory codes describe the driver very accurately.
If you can read a seas factory code you can tell the size, diaphragm material, surround material, magnet size, number of voice coil windings and layers, voice coil size, phase plug and a lot more just by looking at the code.
Examples:
27TFFC: 27 mm, tweeter, fabric dome, ferrofluid, chamber
L22RN4X/P: Aluminium diaphragm, 22 cm. diameter, rubber surround, 1,5" VC diameter, 4-layer VC, extra large magnet, phase plug
Makes a lot more sense this way
/U.
Sorry for the interruption, I just had to get this one off my chest
Because they are the official ones and the only ones used universally around the world. The different code system you mention are only used in Germany, Belgium and the Netherlands as far as I know. It's the same with Vifa and Seas drivers which have different order codes in Germany, Belgium and the Netherlands than in the rest of the world (for some stupid reason unknown to meDIY_Peter said:
. The factory codes describe the driver very accurately. If you can read a seas factory code you can tell the size, diaphragm material, surround material, magnet size, number of voice coil windings and layers, voice coil size, phase plug and a lot more just by looking at the code.
Examples:
27TFFC: 27 mm, tweeter, fabric dome, ferrofluid, chamber
L22RN4X/P: Aluminium diaphragm, 22 cm. diameter, rubber surround, 1,5" VC diameter, 4-layer VC, extra large magnet, phase plug
Makes a lot more sense this way
/U.
Sorry for the interruption, I just had to get this one off my chest
OT: BSC
This means that if I have a 9" wide enclosure (0.225m), and I take the numerator to be a nice round 100 (sort of in between your two figures), I'll have to get additional bass to operate from the bottom of the frequency range up to about 450Hz? I guess if I have four midbass drivers, I can do this by keeping two midbass drivers operating flat through their range, and add a passive xo to the other two, to give them a low-pass at 450Hz? Did I understand you right?sreten said:
have you looked at these.
Very very good sound qyuality I am for sure on this.
I have used the 2 and the 6 and the new changes he has done to the tweeters make them a high quality tweeter for a very good price.
AlT2 tweeter
Very very good sound qyuality I am for sure on this.
I have used the 2 and the 6 and the new changes he has done to the tweeters make them a high quality tweeter for a very good price.
AlT2 tweeter
Re: the BG-GR-Research tweeters
I wonder how these drivers will compare sound wise with the Seas 27TDFC or the Audax TM025F1? Just curious... what other tweeters have you used, and how do these GR-Research ones compare with them?
I wasn't even aware of their existence, thanks. Their prices seem higher than some of the alternatives we've discussed here, but then they claim to actually do a response curve measurement and supply matched pairs. This puts them in the same league as what North Creek claims to do.RAW said:
I wonder how these drivers will compare sound wise with the Seas 27TDFC or the Audax TM025F1? Just curious... what other tweeters have you used, and how do these GR-Research ones compare with them?
Regarding the baffle step at 115/W; this figure was obtained from the web, Elliot's site IIRC.
If you find it to be off, you could try using the diagonal instead:
115 / SQRT(width^2 + height^2)
I don't really think the height figures into it, though, except while listening far from the speaker.
Ideally, you drop the bafflestep-compensation from the speaker itself, and do yourself the favour of making an active room+baffle compensation unit with three parametric equalizers and a variable baffle step compensator.
Could also add eq to bridge the gap between speaker rolloff and room boundary gain.
If you biamp an 0.5 channel, you could do the compensation only for the 0.5 channel, and not worry so much about the potential loss of quality.
If you find it to be off, you could try using the diagonal instead:
115 / SQRT(width^2 + height^2)
I don't really think the height figures into it, though, except while listening far from the speaker.
Ideally, you drop the bafflestep-compensation from the speaker itself, and do yourself the favour of making an active room+baffle compensation unit with three parametric equalizers and a variable baffle step compensator.
Could also add eq to bridge the gap between speaker rolloff and room boundary gain.
If you biamp an 0.5 channel, you could do the compensation only for the 0.5 channel, and not worry so much about the potential loss of quality.
RAW said:
Are you sure ? Given that cost is a very important issue and
IMO most of the tweeters discussed here probably will be
well good enough for the intended application.
The issue here is "Bang for Buck" as the americans say,
but with the emphasis on the least Buck possible as far
as I can tell.
I'd say its between the NC's and the Dayton.
sreten.tweeter under $25
you can check out the GR Research site (www.gr~research.com). They have their GR-T1 for $30 a matched pair unshielded.
you can check out the GR Research site (www.gr~research.com). They have their GR-T1 for $30 a matched pair unshielded.
I've been thinking very seriously about both your inputs, regarding BSC and comb filtering problems. I think I'll keep the BSC option open in my design, and probably try some passive line-level filtering after I get to break in and listen to the speakers. It should be quite simple to add BSC shelving filters to two of my four drivers.sreten said:
I have two approaches to BSC: (i) do a shelving filter on all four midbass drivers, or (ii) do a 6dB low-pass on two of the four midbass drivers, and have an option to fine-tune the step size, i.e. control whether I put in 3dB or 4dB or 6dB gain, depending on listening tests. Which of these two approaches I take depends partly on my second question about comb filtering seriousness...
The other question I have is about this comb filtering thing. Many members here are very concerned about it, but there seems to be some very well-regarded speaker designs which seem to do nothing about it... e.g. the Straight 8. How do those work? That one's a TMMMMMMMM design. If that works, won't my TMMMM work too?
Sorry if my doubts are uber-simple, but I'm just figuring my way through all this...
Re-awakening this thread...
Okay guys, I need your inputs once again on this old topic. I'd started this thread to ask you about the best inexpensive tweeters, and I've got all your answers. I've resumed my diy activity after quite a big gap, and I'm now facing another problem with tweeter and xo design: I want to xo lower than I thought.
So, out of all these tweeters that you've listed, which can handle an xo point of between 1400-1800Hz, if I'm willing to go 4th order acoustic?
The tweeters you've recommended are:
Okay guys, I need your inputs once again on this old topic. I'd started this thread to ask you about the best inexpensive tweeters, and I've got all your answers. I've resumed my diy activity after quite a big gap, and I'm now facing another problem with tweeter and xo design: I want to xo lower than I thought.
So, out of all these tweeters that you've listed, which can handle an xo point of between 1400-1800Hz, if I'm willing to go 4th order acoustic?
The tweeters you've recommended are:
- Dayton (DC28F? ES25F?)
- Peerless 811815
- North Creek D25-06
- Seas TDFC/TFFC
- GR-Research tweeters
- Audax TM025F1
- Morel MDT20/30
- One or two of the venerable Vifas
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.