| JRKO |
Having been away from all things DIY for a while, and being better off financially (cc paid off and better paid job) I wanted some advice before embarking on a 'journey into sound'
I am using Tannoy HPD 385 DC's but feel I am lacking in the low region and losing out on the midband sometimes.
I have the feeling that dedicated Sub(s?) could bring me eternal bliss.... ;)
The Tannoys drop off slowly from 100hz down and I dont think the room helps much with some one note booms. Would these drivers be acceptable as mid/highs and if so what sub(s) design would work well with them?
3ways are supposedly great as they use one driver to cover the mid section where the ear is most sensitive (the Tannoy drivers crossover gently at around 1000hz between mid & high) and I thought that by adding some power assisted bass I could get the 'whole sound' |
|
|
| richie00boy |
| How big is your room? If the Tannoy's drop off from about 100Hz then they will benefit from a sub or two. |
|
|
| JRKO |
My room is abour 17 by 21 foot and 8 'n a bit tall.
The Tannoys are quite efficient - 92-93dB/w/m I think. Would the sub need to be of a similar efficiency? |
|
|
| richie00boy |
No the sub efficiency is irrelevant as it should be driven by it's own amplifier.
In a room of that size you should be able to fill it out better with bass from a sub, adding a lot of depth and taking the strain off the Tannoy's. What is your budget? |
|
|
| JRKO |
Just paid off the credit card:devilr:
On the other hand the wife says :whazzat: 'don't go blowing the lot on speakers again'.....so reasonable would be the word I'd use.
And that is reasonable to the wife.
I thought that if I have low frequency reinforcement I could make the Tannoy cab smaller and get some WAF that way |
|
|
| sreten |
Hi,
Adding a sub to a pair of 15" Tannoy drivers ? :scratch: are you mad ? :boggled:
Seriously what cabinets are they in ? consider detuning the ports
for more deep bass and then adding some line level bass boost.
No sub required IMO, what amplifier do you have ?
:)/sreten. |
|
|
| richie00boy |
| :bigeyes: didn't realise they were 15 inch. Yes definitely something wrong if they aren't doing the business. |
|
|
| JRKO |
They are in Berkerly cabs which have two front firing ports a touch over 40mm dia and about 150mm long.
I have a Jungson 88D Class A Amp driving them but seem to be getting some of the low bass sucked out. Its strange as I get some low stuff but there seems to be a gap in the bass. Maybe the room is reinforcing some of the very low bass but the slightly higer stuff if not benifitting from the rooms 'modes'
Who knows? |
|
|
| richie00boy |
| How big/what volume are the cabinets? 150mm long doesn't sound like it's tuned very low... |
|
|
| JRKO |
| Standard cabs are 754mm tall 500mm wide and 308mm deep. Made of good ol' HD chipboad with what tannoy described as 'massive internal bracing' ie a 100mm wide brace running fromt to back just below the driver. |
|
|
| sreten |
Hi,
You can experiment by closing off one port (sock), will detune the
other port by half an octave and possibly extend bass by half an
octave albeit at a lower level.
Then I suggest you read up on line level passive EQing, line level
BSC (baffle step compensation) circuits are a good place to start.
http://sound.westhost.com/bafflestep.htm
Though choose your frequencies for lower bass somwhat.
Really need driver parameters and the internal volume of the box,
find them on the web and post them here, I'll model the alignment.
:)/sreten. |
|
|
| JRKO |
Hi sreten, just noticed you are in Brighton. I am just down the sunshine coast in Newhaven.
I will get the peramiters together and post them asap.
Many thanks for the help so far. |
|
|
| Collo |
JRKO
I make the tuning frequency to be around 24hz. Blocking one port drops it to 17hz, which probably isn't what you're looking for.
Maybe the room node idea needs investigating further
regards
Collo |
|
|
| JRKO |
Specs from Tannoy
Re 5.7 ohms
Fs 22Hz
Qms 2.4
Qes 0.2
Qts 0.18
Bl 18.72 na
Cms 0.58mm/N
Mms 90g
Sd 770 sq. sm
Vas 483l
Rms 5.1 mech ohms
Sensitivty @ 2.83v/1m 94.3db
There are specs that were mesured by someone @ www.hilberink.nl/codehans/tannoy39.htm that are different from these. My drivers were recenlty refurbisheded by Lockwood and have double the power handling - now up to 150w
In the original Tannoy docs they say that a sealed box is also fine. Would this help and tighten up the bass?
I am guessing this is in the wrong place now. Although a 15 inch driver probably counts as a sub anyway! |
|
|
| richie00boy |
| If the speakers have been refurbished and now sport double the thermal power handling, the parameters from Tannoy and that other bloke's are useless. I'm afraid you need to measure them yourself. |
|
|
| mike.e |
| If the Qts is ~0.2 I wouldnt expect any low bass - only efficient midrange. Add a sub. |
|
|
| BassAwdyO |
| If you suspect room modes ar the issue play around with placement and see if that helps(assuming you can play around with placement). |
|
|
| JRKO |
| I have emailed the guys at lockwood to get some new TS specs. I am assuming that the cones come from Tannoy as they are perfect replacements including the 'girdacoustic ribs' |
|
|
| JRKO |
| Here are the specs. The cones are original Tannoy replacements and these are the specs they provided with them. |
|
|
| sreten |
Hi,
Hmmm....... low bass doesn't model that well but its well damped.
I estimated box volume at 80L, means tuned quite low.
Still I think some line level bass boost would work wonders if
your normal listening levels get nowhere near clipping levels.
:)/sreten. |
|
|
| JRKO |
Not too sure what you mean when you say line level bass boost.
Do you mean bumping it up before amplification?
If this is the case then I am stuck as I am using an integrated amp. I could always try some GRF type cabs (either corner loaded or the 5 foot tall rectangular ones)
I love the mid & highs the Tannoys provide
Or I could just make cabs optimised for mid frequencies from the driver and add a whumping great sub:D |
|
|
| sreten |
| quote: | Originally posted by JRKO
Not too sure what you mean when you say line level bass boost.
Do you mean bumping it up before amplification?
If this is the case then I am stuck as I am using an integrated amp.
:D |
Hi,
In my integrated amplifier I modded the feedback loop
of the power amplifier to boost low bass by up to to 8dB.
Very easy to do.
:)/sreten. |
|
|
| JRKO |
The way you say it makes it sound really easy . . . . for an EE;)
I really would not be that confident about opening up my amp. First my wife will kill me if i break it, second although I have made some working gainclones I would be worried about making a crappy solder joint and blowing the thing up......it cost me a few pennies. |
|
|
| richie00boy |
| No need to open anything up, just build a little box with a boosting (high q) filter in. |
|
|
| 4fun |
Hi!
Those modeling this speaker, isn't a passive filter included with a certain series resistance?
If so, have passive filters been altered? Lower resistance coils?
Q may have been lowered. |
|
|
| JRKO |
bubbuuulelbobobllbbobooblllleeeee
Thats the sound of me being out of my depth.....and slipping under the water.
Think no electronics experiance and then subtract an iq of 200:xeye: |
|
|
| JRKO |
I have down loaded a basic version of WinISD and have entered the basic TS specs as posted previously. I cant work out the rest but I am sure as with all things electrical there are calculations to generate the missing info.
I have used what specs I have and I dont seem to be able to make a hige amont of difference whatever I do to the ports or the cabinet. Even a sealed cabinet has almost the same roll off.
What gives (is it just me?) |
|
|
| sreten |
| quote: | Originally posted by 4fun
Hi!
Those modeling this speaker, isn't a passive filter included with a certain series resistance?
If so, have passive filters been altered? Lower resistance coils?
Q may have been lowered. |
Hi,
you are correct I didn't include the effects of series resistance
of the crossover coils, which raises the effective Qts of the driver.
See new Qts with series inductor here http://www.mhsoft.nl/spk_calc.asp
| quote: | Originally posted by JRKO
I have down loaded a basic version of WinISD and have entered the basic TS specs as posted previously. I cant work out the rest but I am sure as with all things electrical there are calculations to generate the missing info.
I have used what specs I have and I dont seem to be able to make a huge amont of difference whatever I do to the ports or the cabinet. Even a sealed cabinet has almost the same roll off.
What gives (is it just me?) |
Nope, you are not doing anything basically wrong. As stated you
need some form of bass boost. Experimenting with putting a BSC
type circuit between the CD player and its input is a possibility.
With 6dB to 10dB maximum boost depending on room gain
placement etc bass down to 30Hz is certainly possible, and
with two 15"s at reproduction levels you can easily hear.
:)/sreten. |
|
|
|
