Just looking for the perfect 5.5" midbass / woofer

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Hi! I am not a speaker / crossover type guy but I know a little. My cult/not-commonly-available speakers are:

- bookshelf
- 8 ohm
- 2-way bass reflex, rear-ported
- 86 db
- 4000 hz crossover point

I blew my woofers. They might have been old TangBands but I don't know. Cannot find them anywhere. At the manufacturer's recommendation, I bought 5.5" silver flutes. They sound terrible.

I think that's because the silver flutes have a sharp 10 db positive spike in their response (their "breakup" point, I read somewhere) that begins at 4000 hz. So, I am hearing plenty of that spike with this 4000 hz crossover point.

Plus, my tweeters are way too loud now. The silver flute woofers are 87db.

So, I want new 5.5" woofers with:

- more than 87 db
- a smooth decline in response above 4000hz, rather than a spikey "breakup"
- useful bass down to 55hz
- in a 5.5" woofer

Is this possible?
Thanks,
Hukk
 
Thank you very much for your suggestions. I may just go with one of them. However they seem pretty far down by the time you get to 70hz.

I guess my 55hz dream is just that, a dream. OK, I'm happy to give on that.

But everything I am finding that has a smooth decline above 4000hz is giving me "down 5db" or more at 100hz.

Is that just mother nature? Or is there something else possibly out there. I'd probably be willing to spend $200 per woofer, although the $$$ woofers don't seem any better in this dept. than reasonable ones.

Thanks,
Hukk
 
What you need to do is redesign the crossover, not buy another woofer.

I hear you. But if I lower the crossover, then I need to fool with the woofer and tweeter caps, and resistors, etc., don't I? Not to mention, I don't know what I'm doing.

I thought if I could just get a smooth roll-off-above-4khz woofer, with above 87dB, I might avoid that thicket of multiple changes. Maybe I just go with your suggestion, and stop worrying about awesomely flat freq response in the bass.
 
diyAudio Member
Joined 2007
Awesomely flat bass to low Hz and 5inch woofers doesn't sound obtainable to me no matter how expensive or well designed the driver.
Why not take the easy route and just use a decent powered subwoofer set-up ( 3 small powered subs ) and a well known bookshelf design ??

5th recommendation of the P-13 ( whether labelled Vifa/Scanspeak or Peerless) is hard to beat and there are well proven designs which may even fit into you existing boxes. The box may need a new baffle but that is easier than building completely new boxes.
5dB down at 100Hz is quite normal for a small driver, 5 inch isn't what I would call a woofer for extended bass, for that you need dual 8s or 10s. if you want loud and deep then dual 12s or 15s even, which is why small powered subs are perfect for lazy builders like me
 
Well getting any 5" driver that will extend smoothly up to 4kHz is quite difficult, most people would cross 5" drivers from 2kHz-3kHz so transducer designers don't do much beyond getting a flat response up to around there. If they can they will grant you a nice smooth roll off, but it isn't deemed necessary if it contradicts their other design priorities. In other words some mild break-up is easily controlled with the crossover if you know what you're doing, so transducer designers often leave some break-up in if it will improve other aspects of the design.

Unless you know exactly what the original drivers frequency response and impedance curve was like, it is reasonable to assume that any change of driver would warrant a change in crossover. Of course this assumes that the original crossovers were correctly designed, either way, buying a new driver with a very flat response would probably improve things, but it isn't guaranteed to work.

5" drivers don't really do down to 50Hz unless they are below around 85dB sensitive. Certainly optimising the crossover would give you much better results then just focussing on bass extension.

For what it's worth, Zaph over at Zaphaudio used to have a design around that worked with a silver flute 5" driver and a vifa tweeter. Zaph doesn't post on these forums much, but there's a chance you could contact him over on the HTguide forums and request the design files/crossover schematics. If the 5" driver is the same, his xover would probably give you a good starting point for modifying what you've already got.
 
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Can you provide the dimensions of your speaker (HxWxD), the thickness of the wood/mdf, the port diameter and length? This will help establish the internal volume and box tuning.

Exterior dimensions:

11.75" high
6.75" wide
11.5" deep at bottom
8.5" deep at top (the front baffle is sloped)

MDF thickness: 5/8 inch

Port: 2" diameter, 5" in length before my ruler touched something squishy
 
diyAudio Member
Joined 2007
Thank you very much for your thoughts here. I'm sorry but I don't know what "5th recommendation of the P-13" means?

Simply that the driver ( Vifa P-13 ) is a good driver for beginners to play with/utilise. easy driver to use, no vices or break-ups to deal with and can use as few as 2 components in the XO.
http://www.diyaudio.com/forums/multi-way/25590-diyaudio-reference-speaker-project.html
Read the thread and you will see what I mean.

Crossover design isn't needed as all the work has been done, you just need to decide which design to use
 
Exterior dimensions:

11.75" high
6.75" wide
11.5" deep at bottom
8.5" deep at top (the front baffle is sloped)

MDF thickness: 5/8 inch

Port: 2" diameter, 5" in length before my ruler touched something squishy

That's what, about 10 liters? :confused:

IF so, 45 Hz tuning freq. on the Scan Speaks I posted with a 2" diameter vent would require a length of about 10 inches - so an elbow bend would be required (..at the very least).

50 Hz tuning freq. would be about 8 inches long under the same conditions.
 
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This is my Silver Flute 8ohm --
Madisound Speaker Store

...do we believe the bass in this freq. response graph? As drawn, bass is MUCH better than the 5 - 5.5 inch drivers I have been seeing, yet, my speakers are not producing much bass. The previous woofers (blown) pumped out a lot more.

Perhaps for "real bass", I should be looking at another type of spec, not the 50-100hz area in a freq. response graph? Or, maybe this graph is just wrong?
 
Try the ScanSpeak 15W/8530K-01 5" Revelator Woofer. In a 20L enclosure, tuned to 29Hz, F3 is 32Hz. The only drawback is low efficiency and power handling. However, you will get solid deep bass.

AudioTechnology 15H 5.5'' midwoofer in a 12L enclosure, tuned to 45Hz, F3 is 55Hz. Much higher efficiency and power handling but less deep bass. I have used this driver in a small 2 way bookshelf and it is amazingly dynamic and puts out a more accurate bass than the Scan 15W.

If you really want deep bass, then I know of no other 5.5'' midwoofer other than the 15W that can do it.

The graphs don't tell much about the bass because once you place the woofers in a box, the freq response is completely different.
 
Try the ScanSpeak 15W/8530K-01 5" Revelator Woofer. In a 20L enclosure, tuned to 29Hz, F3 is 32Hz. The only drawback is low efficiency and power handling. However, you will get solid deep bass.

AudioTechnology 15H 5.5'' midwoofer in a 12L enclosure, tuned to 45Hz, F3 is 55Hz. Much higher efficiency and power handling but less deep bass. I have used this driver in a small 2 way bookshelf and it is amazingly dynamic and puts out a more accurate bass than the Scan 15W.

If you really want deep bass, then I know of no other 5.5'' midwoofer other than the 15W that can do it.

The graphs don't tell much about the bass because once you place the woofers in a box, the freq response is completely different.

I think those drivers are a little bit over the top for what the original poster is trying to achieve!
 
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